symbian-qemu-0.9.1-12/python-2.6.1/Python/ast.c
changeset 1 2fb8b9db1c86
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/symbian-qemu-0.9.1-12/python-2.6.1/Python/ast.c	Fri Jul 31 15:01:17 2009 +0100
@@ -0,0 +1,3422 @@
+/*
+ * This file includes functions to transform a concrete syntax tree (CST) to
+ * an abstract syntax tree (AST).  The main function is PyAST_FromNode().
+ *
+ */
+#include "Python.h"
+#include "Python-ast.h"
+#include "grammar.h"
+#include "node.h"
+#include "pyarena.h"
+#include "ast.h"
+#include "token.h"
+#include "parsetok.h"
+#include "graminit.h"
+
+#include <assert.h>
+
+/* Data structure used internally */
+struct compiling {
+    char *c_encoding; /* source encoding */
+    int c_future_unicode; /* __future__ unicode literals flag */
+    PyArena *c_arena; /* arena for allocating memeory */
+    const char *c_filename; /* filename */
+};
+
+static asdl_seq *seq_for_testlist(struct compiling *, const node *);
+static expr_ty ast_for_expr(struct compiling *, const node *);
+static stmt_ty ast_for_stmt(struct compiling *, const node *);
+static asdl_seq *ast_for_suite(struct compiling *, const node *);
+static asdl_seq *ast_for_exprlist(struct compiling *, const node *,
+                                  expr_context_ty);
+static expr_ty ast_for_testlist(struct compiling *, const node *);
+static stmt_ty ast_for_classdef(struct compiling *, const node *, asdl_seq *);
+static expr_ty ast_for_testlist_gexp(struct compiling *, const node *);
+
+/* Note different signature for ast_for_call */
+static expr_ty ast_for_call(struct compiling *, const node *, expr_ty);
+
+static PyObject *parsenumber(struct compiling *, const char *);
+static PyObject *parsestr(struct compiling *, const char *);
+static PyObject *parsestrplus(struct compiling *, const node *n);
+
+#ifndef LINENO
+#define LINENO(n)       ((n)->n_lineno)
+#endif
+
+static identifier
+new_identifier(const char* n, PyArena *arena) {
+    PyObject* id = PyString_InternFromString(n);
+    if (id != NULL)
+        PyArena_AddPyObject(arena, id);
+    return id;
+}
+
+#define NEW_IDENTIFIER(n) new_identifier(STR(n), c->c_arena)
+
+/* This routine provides an invalid object for the syntax error.
+   The outermost routine must unpack this error and create the
+   proper object.  We do this so that we don't have to pass
+   the filename to everything function.
+
+   XXX Maybe we should just pass the filename...
+*/
+
+static int
+ast_error(const node *n, const char *errstr)
+{
+    PyObject *u = Py_BuildValue("zi", errstr, LINENO(n));
+    if (!u)
+        return 0;
+    PyErr_SetObject(PyExc_SyntaxError, u);
+    Py_DECREF(u);
+    return 0;
+}
+
+static void
+ast_error_finish(const char *filename)
+{
+    PyObject *type, *value, *tback, *errstr, *loc, *tmp;
+    long lineno;
+
+    assert(PyErr_Occurred());
+    if (!PyErr_ExceptionMatches(PyExc_SyntaxError))
+        return;
+
+    PyErr_Fetch(&type, &value, &tback);
+    errstr = PyTuple_GetItem(value, 0);
+    if (!errstr)
+        return;
+    Py_INCREF(errstr);
+    lineno = PyInt_AsLong(PyTuple_GetItem(value, 1));
+    if (lineno == -1) {
+        Py_DECREF(errstr);
+        return;
+    }
+    Py_DECREF(value);
+
+    loc = PyErr_ProgramText(filename, lineno);
+    if (!loc) {
+        Py_INCREF(Py_None);
+        loc = Py_None;
+    }
+    tmp = Py_BuildValue("(zlOO)", filename, lineno, Py_None, loc);
+    Py_DECREF(loc);
+    if (!tmp) {
+        Py_DECREF(errstr);
+        return;
+    }
+    value = PyTuple_Pack(2, errstr, tmp);
+    Py_DECREF(errstr);
+    Py_DECREF(tmp);
+    if (!value)
+        return;
+    PyErr_Restore(type, value, tback);
+}
+
+static int
+ast_warn(struct compiling *c, const node *n, char *msg)
+{
+    if (PyErr_WarnExplicit(PyExc_SyntaxWarning, msg, c->c_filename, LINENO(n),
+                           NULL, NULL) < 0) {
+        /* if -Werr, change it to a SyntaxError */
+        if (PyErr_Occurred() && PyErr_ExceptionMatches(PyExc_SyntaxWarning))
+            ast_error(n, msg);
+        return 0;
+    }
+    return 1;
+}
+
+static int
+forbidden_check(struct compiling *c, const node *n, const char *x)
+{
+    if (!strcmp(x, "None"))
+        return ast_error(n, "assignment to None");
+    if (Py_Py3kWarningFlag && !(strcmp(x, "True") && strcmp(x, "False")) &&
+        !ast_warn(c, n, "assignment to True or False is forbidden in 3.x"))
+        return 0;
+    return 1;
+}
+
+/* num_stmts() returns number of contained statements.
+
+   Use this routine to determine how big a sequence is needed for
+   the statements in a parse tree.  Its raison d'etre is this bit of
+   grammar:
+
+   stmt: simple_stmt | compound_stmt
+   simple_stmt: small_stmt (';' small_stmt)* [';'] NEWLINE
+
+   A simple_stmt can contain multiple small_stmt elements joined
+   by semicolons.  If the arg is a simple_stmt, the number of
+   small_stmt elements is returned.
+*/
+
+static int
+num_stmts(const node *n)
+{
+    int i, l;
+    node *ch;
+
+    switch (TYPE(n)) {
+        case single_input:
+            if (TYPE(CHILD(n, 0)) == NEWLINE)
+                return 0;
+            else
+                return num_stmts(CHILD(n, 0));
+        case file_input:
+            l = 0;
+            for (i = 0; i < NCH(n); i++) {
+                ch = CHILD(n, i);
+                if (TYPE(ch) == stmt)
+                    l += num_stmts(ch);
+            }
+            return l;
+        case stmt:
+            return num_stmts(CHILD(n, 0));
+        case compound_stmt:
+            return 1;
+        case simple_stmt:
+            return NCH(n) / 2; /* Divide by 2 to remove count of semi-colons */
+        case suite:
+            if (NCH(n) == 1)
+                return num_stmts(CHILD(n, 0));
+            else {
+                l = 0;
+                for (i = 2; i < (NCH(n) - 1); i++)
+                    l += num_stmts(CHILD(n, i));
+                return l;
+            }
+        default: {
+            char buf[128];
+
+            sprintf(buf, "Non-statement found: %d %d\n",
+                    TYPE(n), NCH(n));
+            Py_FatalError(buf);
+        }
+    }
+    assert(0);
+    return 0;
+}
+
+/* Transform the CST rooted at node * to the appropriate AST
+*/
+
+mod_ty
+PyAST_FromNode(const node *n, PyCompilerFlags *flags, const char *filename,
+               PyArena *arena)
+{
+    int i, j, k, num;
+    asdl_seq *stmts = NULL;
+    stmt_ty s;
+    node *ch;
+    struct compiling c;
+
+    if (flags && flags->cf_flags & PyCF_SOURCE_IS_UTF8) {
+        c.c_encoding = "utf-8";
+        if (TYPE(n) == encoding_decl) {
+            ast_error(n, "encoding declaration in Unicode string");
+            goto error;
+        }
+    } else if (TYPE(n) == encoding_decl) {
+        c.c_encoding = STR(n);
+        n = CHILD(n, 0);
+    } else {
+        c.c_encoding = NULL;
+    }
+    c.c_future_unicode = flags && flags->cf_flags & CO_FUTURE_UNICODE_LITERALS;
+    c.c_arena = arena;
+    c.c_filename = filename;
+
+    k = 0;
+    switch (TYPE(n)) {
+        case file_input:
+            stmts = asdl_seq_new(num_stmts(n), arena);
+            if (!stmts)
+                return NULL;
+            for (i = 0; i < NCH(n) - 1; i++) {
+                ch = CHILD(n, i);
+                if (TYPE(ch) == NEWLINE)
+                    continue;
+                REQ(ch, stmt);
+                num = num_stmts(ch);
+                if (num == 1) {
+                    s = ast_for_stmt(&c, ch);
+                    if (!s)
+                        goto error;
+                    asdl_seq_SET(stmts, k++, s);
+                }
+                else {
+                    ch = CHILD(ch, 0);
+                    REQ(ch, simple_stmt);
+                    for (j = 0; j < num; j++) {
+                        s = ast_for_stmt(&c, CHILD(ch, j * 2));
+                        if (!s)
+                            goto error;
+                        asdl_seq_SET(stmts, k++, s);
+                    }
+                }
+            }
+            return Module(stmts, arena);
+        case eval_input: {
+            expr_ty testlist_ast;
+
+            /* XXX Why not gen_for here? */
+            testlist_ast = ast_for_testlist(&c, CHILD(n, 0));
+            if (!testlist_ast)
+                goto error;
+            return Expression(testlist_ast, arena);
+        }
+        case single_input:
+            if (TYPE(CHILD(n, 0)) == NEWLINE) {
+                stmts = asdl_seq_new(1, arena);
+                if (!stmts)
+                    goto error;
+                asdl_seq_SET(stmts, 0, Pass(n->n_lineno, n->n_col_offset,
+                                            arena));
+                if (!asdl_seq_GET(stmts, 0))
+                    goto error;
+                return Interactive(stmts, arena);
+            }
+            else {
+                n = CHILD(n, 0);
+                num = num_stmts(n);
+                stmts = asdl_seq_new(num, arena);
+                if (!stmts)
+                    goto error;
+                if (num == 1) {
+                    s = ast_for_stmt(&c, n);
+                    if (!s)
+                        goto error;
+                    asdl_seq_SET(stmts, 0, s);
+                }
+                else {
+                    /* Only a simple_stmt can contain multiple statements. */
+                    REQ(n, simple_stmt);
+                    for (i = 0; i < NCH(n); i += 2) {
+                        if (TYPE(CHILD(n, i)) == NEWLINE)
+                            break;
+                        s = ast_for_stmt(&c, CHILD(n, i));
+                        if (!s)
+                            goto error;
+                        asdl_seq_SET(stmts, i / 2, s);
+                    }
+                }
+
+                return Interactive(stmts, arena);
+            }
+        default:
+            PyErr_Format(PyExc_SystemError,
+                         "invalid node %d for PyAST_FromNode", TYPE(n));
+            goto error;
+    }
+ error:
+    ast_error_finish(filename);
+    return NULL;
+}
+
+/* Return the AST repr. of the operator represented as syntax (|, ^, etc.)
+*/
+
+static operator_ty
+get_operator(const node *n)
+{
+    switch (TYPE(n)) {
+        case VBAR:
+            return BitOr;
+        case CIRCUMFLEX:
+            return BitXor;
+        case AMPER:
+            return BitAnd;
+        case LEFTSHIFT:
+            return LShift;
+        case RIGHTSHIFT:
+            return RShift;
+        case PLUS:
+            return Add;
+        case MINUS:
+            return Sub;
+        case STAR:
+            return Mult;
+        case SLASH:
+            return Div;
+        case DOUBLESLASH:
+            return FloorDiv;
+        case PERCENT:
+            return Mod;
+        default:
+            return (operator_ty)0;
+    }
+}
+
+/* Set the context ctx for expr_ty e, recursively traversing e.
+
+   Only sets context for expr kinds that "can appear in assignment context"
+   (according to ../Parser/Python.asdl).  For other expr kinds, it sets
+   an appropriate syntax error and returns false.
+*/
+
+static int
+set_context(struct compiling *c, expr_ty e, expr_context_ty ctx, const node *n)
+{
+    asdl_seq *s = NULL;
+    /* If a particular expression type can't be used for assign / delete,
+       set expr_name to its name and an error message will be generated.
+    */
+    const char* expr_name = NULL;
+
+    /* The ast defines augmented store and load contexts, but the
+       implementation here doesn't actually use them.  The code may be
+       a little more complex than necessary as a result.  It also means
+       that expressions in an augmented assignment have a Store context.
+       Consider restructuring so that augmented assignment uses
+       set_context(), too.
+    */
+    assert(ctx != AugStore && ctx != AugLoad);
+
+    switch (e->kind) {
+        case Attribute_kind:
+            if (ctx == Store && !forbidden_check(c, n,
+                                PyBytes_AS_STRING(e->v.Attribute.attr)))
+                    return 0;
+            e->v.Attribute.ctx = ctx;
+            break;
+        case Subscript_kind:
+            e->v.Subscript.ctx = ctx;
+            break;
+        case Name_kind:
+            if (ctx == Store && !forbidden_check(c, n,
+                                PyBytes_AS_STRING(e->v.Name.id)))
+                    return 0;
+            e->v.Name.ctx = ctx;
+            break;
+        case List_kind:
+            e->v.List.ctx = ctx;
+            s = e->v.List.elts;
+            break;
+        case Tuple_kind:
+            if (asdl_seq_LEN(e->v.Tuple.elts) == 0) 
+                return ast_error(n, "can't assign to ()");
+            e->v.Tuple.ctx = ctx;
+            s = e->v.Tuple.elts;
+            break;
+        case Lambda_kind:
+            expr_name = "lambda";
+            break;
+        case Call_kind:
+            expr_name = "function call";
+            break;
+        case BoolOp_kind:
+        case BinOp_kind:
+        case UnaryOp_kind:
+            expr_name = "operator";
+            break;
+        case GeneratorExp_kind:
+            expr_name = "generator expression";
+            break;
+        case Yield_kind:
+            expr_name = "yield expression";
+            break;
+        case ListComp_kind:
+            expr_name = "list comprehension";
+            break;
+        case Dict_kind:
+        case Num_kind:
+        case Str_kind:
+            expr_name = "literal";
+            break;
+        case Compare_kind:
+            expr_name = "comparison";
+            break;
+        case Repr_kind:
+            expr_name = "repr";
+            break;
+        case IfExp_kind:
+            expr_name = "conditional expression";
+            break;
+        default:
+            PyErr_Format(PyExc_SystemError, 
+                         "unexpected expression in assignment %d (line %d)", 
+                         e->kind, e->lineno);
+            return 0;
+    }
+    /* Check for error string set by switch */
+    if (expr_name) {
+        char buf[300];
+        PyOS_snprintf(buf, sizeof(buf),
+                      "can't %s %s",
+                      ctx == Store ? "assign to" : "delete",
+                      expr_name);
+        return ast_error(n, buf);
+    }
+
+    /* If the LHS is a list or tuple, we need to set the assignment
+       context for all the contained elements.  
+    */
+    if (s) {
+        int i;
+
+        for (i = 0; i < asdl_seq_LEN(s); i++) {
+            if (!set_context(c, (expr_ty)asdl_seq_GET(s, i), ctx, n))
+                return 0;
+        }
+    }
+    return 1;
+}
+
+static operator_ty
+ast_for_augassign(struct compiling *c, const node *n)
+{
+    REQ(n, augassign);
+    n = CHILD(n, 0);
+    switch (STR(n)[0]) {
+        case '+':
+            return Add;
+        case '-':
+            return Sub;
+        case '/':
+            if (STR(n)[1] == '/')
+                return FloorDiv;
+            else
+                return Div;
+        case '%':
+            return Mod;
+        case '<':
+            return LShift;
+        case '>':
+            return RShift;
+        case '&':
+            return BitAnd;
+        case '^':
+            return BitXor;
+        case '|':
+            return BitOr;
+        case '*':
+            if (STR(n)[1] == '*')
+                return Pow;
+            else
+                return Mult;
+        default:
+            PyErr_Format(PyExc_SystemError, "invalid augassign: %s", STR(n));
+            return (operator_ty)0;
+    }
+}
+
+static cmpop_ty
+ast_for_comp_op(struct compiling *c, const node *n)
+{
+    /* comp_op: '<'|'>'|'=='|'>='|'<='|'<>'|'!='|'in'|'not' 'in'|'is'
+               |'is' 'not'
+    */
+    REQ(n, comp_op);
+    if (NCH(n) == 1) {
+        n = CHILD(n, 0);
+        switch (TYPE(n)) {
+            case LESS:
+                return Lt;
+            case GREATER:
+                return Gt;
+            case EQEQUAL:                       /* == */
+                return Eq;
+            case LESSEQUAL:
+                return LtE;
+            case GREATEREQUAL:
+                return GtE;
+            case NOTEQUAL:
+                return NotEq;
+            case NAME:
+                if (strcmp(STR(n), "in") == 0)
+                    return In;
+                if (strcmp(STR(n), "is") == 0)
+                    return Is;
+            default:
+                PyErr_Format(PyExc_SystemError, "invalid comp_op: %s",
+                             STR(n));
+                return (cmpop_ty)0;
+        }
+    }
+    else if (NCH(n) == 2) {
+        /* handle "not in" and "is not" */
+        switch (TYPE(CHILD(n, 0))) {
+            case NAME:
+                if (strcmp(STR(CHILD(n, 1)), "in") == 0)
+                    return NotIn;
+                if (strcmp(STR(CHILD(n, 0)), "is") == 0)
+                    return IsNot;
+            default:
+                PyErr_Format(PyExc_SystemError, "invalid comp_op: %s %s",
+                             STR(CHILD(n, 0)), STR(CHILD(n, 1)));
+                return (cmpop_ty)0;
+        }
+    }
+    PyErr_Format(PyExc_SystemError, "invalid comp_op: has %d children",
+                 NCH(n));
+    return (cmpop_ty)0;
+}
+
+static asdl_seq *
+seq_for_testlist(struct compiling *c, const node *n)
+{
+    /* testlist: test (',' test)* [','] */
+    asdl_seq *seq;
+    expr_ty expression;
+    int i;
+    assert(TYPE(n) == testlist ||
+           TYPE(n) == listmaker ||
+           TYPE(n) == testlist_gexp ||
+           TYPE(n) == testlist_safe ||
+           TYPE(n) == testlist1);
+
+    seq = asdl_seq_new((NCH(n) + 1) / 2, c->c_arena);
+    if (!seq)
+        return NULL;
+
+    for (i = 0; i < NCH(n); i += 2) {
+        assert(TYPE(CHILD(n, i)) == test || TYPE(CHILD(n, i)) == old_test);
+
+        expression = ast_for_expr(c, CHILD(n, i));
+        if (!expression)
+            return NULL;
+
+        assert(i / 2 < seq->size);
+        asdl_seq_SET(seq, i / 2, expression);
+    }
+    return seq;
+}
+
+static expr_ty
+compiler_complex_args(struct compiling *c, const node *n)
+{
+    int i, len = (NCH(n) + 1) / 2;
+    expr_ty result;
+    asdl_seq *args = asdl_seq_new(len, c->c_arena);
+    if (!args)
+        return NULL;
+
+    /* fpdef: NAME | '(' fplist ')'
+       fplist: fpdef (',' fpdef)* [',']
+    */
+    REQ(n, fplist);
+    for (i = 0; i < len; i++) {
+        PyObject *arg_id;
+        const node *fpdef_node = CHILD(n, 2*i);
+        const node *child;
+        expr_ty arg;
+set_name:
+        /* fpdef_node is either a NAME or an fplist */
+        child = CHILD(fpdef_node, 0);
+        if (TYPE(child) == NAME) {
+            if (!forbidden_check(c, n, STR(child)))
+                return NULL;
+            arg_id = NEW_IDENTIFIER(child);
+            if (!arg_id)
+                return NULL;
+            arg = Name(arg_id, Store, LINENO(child), child->n_col_offset,
+                       c->c_arena);
+        }
+        else {
+            assert(TYPE(fpdef_node) == fpdef);
+            /* fpdef_node[0] is not a name, so it must be '(', get CHILD[1] */
+            child = CHILD(fpdef_node, 1);
+            assert(TYPE(child) == fplist);
+            /* NCH == 1 means we have (x), we need to elide the extra parens */
+            if (NCH(child) == 1) {
+                fpdef_node = CHILD(child, 0);
+                assert(TYPE(fpdef_node) == fpdef);
+                goto set_name;
+            }
+            arg = compiler_complex_args(c, child);
+        }
+        asdl_seq_SET(args, i, arg);
+    }
+
+    result = Tuple(args, Store, LINENO(n), n->n_col_offset, c->c_arena);
+    if (!set_context(c, result, Store, n))
+        return NULL;
+    return result;
+}
+
+
+/* Create AST for argument list. */
+
+static arguments_ty
+ast_for_arguments(struct compiling *c, const node *n)
+{
+    /* parameters: '(' [varargslist] ')'
+       varargslist: (fpdef ['=' test] ',')* ('*' NAME [',' '**' NAME]
+            | '**' NAME) | fpdef ['=' test] (',' fpdef ['=' test])* [',']
+    */
+    int i, j, k, n_args = 0, n_defaults = 0, found_default = 0;
+    asdl_seq *args, *defaults;
+    identifier vararg = NULL, kwarg = NULL;
+    node *ch;
+
+    if (TYPE(n) == parameters) {
+        if (NCH(n) == 2) /* () as argument list */
+            return arguments(NULL, NULL, NULL, NULL, c->c_arena);
+        n = CHILD(n, 1);
+    }
+    REQ(n, varargslist);
+
+    /* first count the number of normal args & defaults */
+    for (i = 0; i < NCH(n); i++) {
+        ch = CHILD(n, i);
+        if (TYPE(ch) == fpdef)
+            n_args++;
+        if (TYPE(ch) == EQUAL)
+            n_defaults++;
+    }
+    args = (n_args ? asdl_seq_new(n_args, c->c_arena) : NULL);
+    if (!args && n_args)
+        return NULL; /* Don't need to goto error; no objects allocated */
+    defaults = (n_defaults ? asdl_seq_new(n_defaults, c->c_arena) : NULL);
+    if (!defaults && n_defaults)
+        return NULL; /* Don't need to goto error; no objects allocated */
+
+    /* fpdef: NAME | '(' fplist ')'
+       fplist: fpdef (',' fpdef)* [',']
+    */
+    i = 0;
+    j = 0;  /* index for defaults */
+    k = 0;  /* index for args */
+    while (i < NCH(n)) {
+        ch = CHILD(n, i);
+        switch (TYPE(ch)) {
+            case fpdef:
+            handle_fpdef:
+                /* XXX Need to worry about checking if TYPE(CHILD(n, i+1)) is
+                   anything other than EQUAL or a comma? */
+                /* XXX Should NCH(n) check be made a separate check? */
+                if (i + 1 < NCH(n) && TYPE(CHILD(n, i + 1)) == EQUAL) {
+                    expr_ty expression = ast_for_expr(c, CHILD(n, i + 2));
+                    if (!expression)
+                        goto error;
+                    assert(defaults != NULL);
+                    asdl_seq_SET(defaults, j++, expression);
+                    i += 2;
+                    found_default = 1;
+                }
+                else if (found_default) {
+                    ast_error(n, 
+                             "non-default argument follows default argument");
+                    goto error;
+                }
+                if (NCH(ch) == 3) {
+                    ch = CHILD(ch, 1);
+                    /* def foo((x)): is not complex, special case. */
+                    if (NCH(ch) != 1) {
+                        /* We have complex arguments, setup for unpacking. */
+                        if (Py_Py3kWarningFlag && !ast_warn(c, ch,
+                            "tuple parameter unpacking has been removed in 3.x"))
+                            goto error;
+                        asdl_seq_SET(args, k++, compiler_complex_args(c, ch));
+                        if (!asdl_seq_GET(args, k-1))
+                                goto error;
+                    } else {
+                        /* def foo((x)): setup for checking NAME below. */
+                        /* Loop because there can be many parens and tuple
+                           unpacking mixed in. */
+                        ch = CHILD(ch, 0);
+                        assert(TYPE(ch) == fpdef);
+                        goto handle_fpdef;
+                    }
+                }
+                if (TYPE(CHILD(ch, 0)) == NAME) {
+                    PyObject *id;
+                    expr_ty name;
+                    if (!forbidden_check(c, n, STR(CHILD(ch, 0))))
+                        goto error;
+                    id = NEW_IDENTIFIER(CHILD(ch, 0));
+                    if (!id)
+                        goto error;
+                    name = Name(id, Param, LINENO(ch), ch->n_col_offset,
+                                c->c_arena);
+                    if (!name)
+                        goto error;
+                    asdl_seq_SET(args, k++, name);
+                                         
+                }
+                i += 2; /* the name and the comma */
+                break;
+            case STAR:
+                if (!forbidden_check(c, CHILD(n, i+1), STR(CHILD(n, i+1))))
+                    goto error;
+                vararg = NEW_IDENTIFIER(CHILD(n, i+1));
+                if (!vararg)
+                    goto error;
+                i += 3;
+                break;
+            case DOUBLESTAR:
+                if (!forbidden_check(c, CHILD(n, i+1), STR(CHILD(n, i+1))))
+                    goto error;
+                kwarg = NEW_IDENTIFIER(CHILD(n, i+1));
+                if (!kwarg)
+                    goto error;
+                i += 3;
+                break;
+            default:
+                PyErr_Format(PyExc_SystemError,
+                             "unexpected node in varargslist: %d @ %d",
+                             TYPE(ch), i);
+                goto error;
+        }
+    }
+
+    return arguments(args, vararg, kwarg, defaults, c->c_arena);
+
+ error:
+    Py_XDECREF(vararg);
+    Py_XDECREF(kwarg);
+    return NULL;
+}
+
+static expr_ty
+ast_for_dotted_name(struct compiling *c, const node *n)
+{
+    expr_ty e;
+    identifier id;
+    int lineno, col_offset;
+    int i;
+
+    REQ(n, dotted_name);
+
+    lineno = LINENO(n);
+    col_offset = n->n_col_offset;
+
+    id = NEW_IDENTIFIER(CHILD(n, 0));
+    if (!id)
+        return NULL;
+    e = Name(id, Load, lineno, col_offset, c->c_arena);
+    if (!e)
+        return NULL;
+
+    for (i = 2; i < NCH(n); i+=2) {
+        id = NEW_IDENTIFIER(CHILD(n, i));
+        if (!id)
+            return NULL;
+        e = Attribute(e, id, Load, lineno, col_offset, c->c_arena);
+        if (!e)
+            return NULL;
+    }
+
+    return e;
+}
+
+static expr_ty
+ast_for_decorator(struct compiling *c, const node *n)
+{
+    /* decorator: '@' dotted_name [ '(' [arglist] ')' ] NEWLINE */
+    expr_ty d = NULL;
+    expr_ty name_expr;
+    
+    REQ(n, decorator);
+    REQ(CHILD(n, 0), AT);
+    REQ(RCHILD(n, -1), NEWLINE);
+    
+    name_expr = ast_for_dotted_name(c, CHILD(n, 1));
+    if (!name_expr)
+        return NULL;
+        
+    if (NCH(n) == 3) { /* No arguments */
+        d = name_expr;
+        name_expr = NULL;
+    }
+    else if (NCH(n) == 5) { /* Call with no arguments */
+        d = Call(name_expr, NULL, NULL, NULL, NULL, LINENO(n),
+                 n->n_col_offset, c->c_arena);
+        if (!d)
+            return NULL;
+        name_expr = NULL;
+    }
+    else {
+        d = ast_for_call(c, CHILD(n, 3), name_expr);
+        if (!d)
+            return NULL;
+        name_expr = NULL;
+    }
+
+    return d;
+}
+
+static asdl_seq*
+ast_for_decorators(struct compiling *c, const node *n)
+{
+    asdl_seq* decorator_seq;
+    expr_ty d;
+    int i;
+    
+    REQ(n, decorators);
+    decorator_seq = asdl_seq_new(NCH(n), c->c_arena);
+    if (!decorator_seq)
+        return NULL;
+        
+    for (i = 0; i < NCH(n); i++) {
+        d = ast_for_decorator(c, CHILD(n, i));
+            if (!d)
+                return NULL;
+            asdl_seq_SET(decorator_seq, i, d);
+    }
+    return decorator_seq;
+}
+
+static stmt_ty
+ast_for_funcdef(struct compiling *c, const node *n, asdl_seq *decorator_seq)
+{
+    /* funcdef: 'def' NAME parameters ':' suite */
+    identifier name;
+    arguments_ty args;
+    asdl_seq *body;
+    int name_i = 1;
+
+    REQ(n, funcdef);
+
+    name = NEW_IDENTIFIER(CHILD(n, name_i));
+    if (!name)
+        return NULL;
+    else if (!forbidden_check(c, CHILD(n, name_i), STR(CHILD(n, name_i))))
+        return NULL;
+    args = ast_for_arguments(c, CHILD(n, name_i + 1));
+    if (!args)
+        return NULL;
+    body = ast_for_suite(c, CHILD(n, name_i + 3));
+    if (!body)
+        return NULL;
+
+    return FunctionDef(name, args, body, decorator_seq, LINENO(n),
+                       n->n_col_offset, c->c_arena);
+}
+
+static stmt_ty
+ast_for_decorated(struct compiling *c, const node *n)
+{
+    /* decorated: decorators (classdef | funcdef) */
+    stmt_ty thing = NULL;
+    asdl_seq *decorator_seq = NULL;
+
+    REQ(n, decorated);
+
+    decorator_seq = ast_for_decorators(c, CHILD(n, 0));
+    if (!decorator_seq)
+      return NULL;
+
+    assert(TYPE(CHILD(n, 1)) == funcdef ||
+	   TYPE(CHILD(n, 1)) == classdef);
+
+    if (TYPE(CHILD(n, 1)) == funcdef) {
+      thing = ast_for_funcdef(c, CHILD(n, 1), decorator_seq);
+    } else if (TYPE(CHILD(n, 1)) == classdef) {
+      thing = ast_for_classdef(c, CHILD(n, 1), decorator_seq);
+    }
+    /* we count the decorators in when talking about the class' or
+       function's line number */
+    if (thing) {
+        thing->lineno = LINENO(n);
+        thing->col_offset = n->n_col_offset;
+    }
+    return thing;
+}
+
+static expr_ty
+ast_for_lambdef(struct compiling *c, const node *n)
+{
+    /* lambdef: 'lambda' [varargslist] ':' test */
+    arguments_ty args;
+    expr_ty expression;
+
+    if (NCH(n) == 3) {
+        args = arguments(NULL, NULL, NULL, NULL, c->c_arena);
+        if (!args)
+            return NULL;
+        expression = ast_for_expr(c, CHILD(n, 2));
+        if (!expression)
+            return NULL;
+    }
+    else {
+        args = ast_for_arguments(c, CHILD(n, 1));
+        if (!args)
+            return NULL;
+        expression = ast_for_expr(c, CHILD(n, 3));
+        if (!expression)
+            return NULL;
+    }
+
+    return Lambda(args, expression, LINENO(n), n->n_col_offset, c->c_arena);
+}
+
+static expr_ty
+ast_for_ifexpr(struct compiling *c, const node *n)
+{
+    /* test: or_test 'if' or_test 'else' test */ 
+    expr_ty expression, body, orelse;
+
+    assert(NCH(n) == 5);
+    body = ast_for_expr(c, CHILD(n, 0));
+    if (!body)
+        return NULL;
+    expression = ast_for_expr(c, CHILD(n, 2));
+    if (!expression)
+        return NULL;
+    orelse = ast_for_expr(c, CHILD(n, 4));
+    if (!orelse)
+        return NULL;
+    return IfExp(expression, body, orelse, LINENO(n), n->n_col_offset,
+                 c->c_arena);
+}
+
+/* XXX(nnorwitz): the listcomp and genexpr code should be refactored
+   so there is only a single version.  Possibly for loops can also re-use
+   the code.
+*/
+
+/* Count the number of 'for' loop in a list comprehension.
+
+   Helper for ast_for_listcomp().
+*/
+
+static int
+count_list_fors(struct compiling *c, const node *n)
+{
+    int n_fors = 0;
+    node *ch = CHILD(n, 1);
+
+ count_list_for:
+    n_fors++;
+    REQ(ch, list_for);
+    if (NCH(ch) == 5)
+        ch = CHILD(ch, 4);
+    else
+        return n_fors;
+ count_list_iter:
+    REQ(ch, list_iter);
+    ch = CHILD(ch, 0);
+    if (TYPE(ch) == list_for)
+        goto count_list_for;
+    else if (TYPE(ch) == list_if) {
+        if (NCH(ch) == 3) {
+            ch = CHILD(ch, 2);
+            goto count_list_iter;
+        }
+        else
+            return n_fors;
+    }
+
+    /* Should never be reached */
+    PyErr_SetString(PyExc_SystemError, "logic error in count_list_fors");
+    return -1;
+}
+
+/* Count the number of 'if' statements in a list comprehension.
+
+   Helper for ast_for_listcomp().
+*/
+
+static int
+count_list_ifs(struct compiling *c, const node *n)
+{
+    int n_ifs = 0;
+
+ count_list_iter:
+    REQ(n, list_iter);
+    if (TYPE(CHILD(n, 0)) == list_for)
+        return n_ifs;
+    n = CHILD(n, 0);
+    REQ(n, list_if);
+    n_ifs++;
+    if (NCH(n) == 2)
+        return n_ifs;
+    n = CHILD(n, 2);
+    goto count_list_iter;
+}
+
+static expr_ty
+ast_for_listcomp(struct compiling *c, const node *n)
+{
+    /* listmaker: test ( list_for | (',' test)* [','] )
+       list_for: 'for' exprlist 'in' testlist_safe [list_iter]
+       list_iter: list_for | list_if
+       list_if: 'if' test [list_iter]
+       testlist_safe: test [(',' test)+ [',']]
+    */
+    expr_ty elt;
+    asdl_seq *listcomps;
+    int i, n_fors;
+    node *ch;
+
+    REQ(n, listmaker);
+    assert(NCH(n) > 1);
+
+    elt = ast_for_expr(c, CHILD(n, 0));
+    if (!elt)
+        return NULL;
+
+    n_fors = count_list_fors(c, n);
+    if (n_fors == -1)
+        return NULL;
+
+    listcomps = asdl_seq_new(n_fors, c->c_arena);
+    if (!listcomps)
+        return NULL;
+
+    ch = CHILD(n, 1);
+    for (i = 0; i < n_fors; i++) {
+        comprehension_ty lc;
+        asdl_seq *t;
+        expr_ty expression;
+        node *for_ch;
+        
+        REQ(ch, list_for);
+        
+        for_ch = CHILD(ch, 1);
+        t = ast_for_exprlist(c, for_ch, Store);
+        if (!t)
+            return NULL;
+        expression = ast_for_testlist(c, CHILD(ch, 3));
+        if (!expression)
+            return NULL;
+        
+        /* Check the # of children rather than the length of t, since
+           [x for x, in ... ] has 1 element in t, but still requires a Tuple.
+        */
+        if (NCH(for_ch) == 1)
+            lc = comprehension((expr_ty)asdl_seq_GET(t, 0), expression, NULL,
+                               c->c_arena);
+        else
+            lc = comprehension(Tuple(t, Store, LINENO(ch), ch->n_col_offset,
+                                     c->c_arena),
+                               expression, NULL, c->c_arena);
+        if (!lc)
+            return NULL;
+
+        if (NCH(ch) == 5) {
+            int j, n_ifs;
+            asdl_seq *ifs;
+            expr_ty list_for_expr;
+
+            ch = CHILD(ch, 4);
+            n_ifs = count_list_ifs(c, ch);
+            if (n_ifs == -1)
+                return NULL;
+
+            ifs = asdl_seq_new(n_ifs, c->c_arena);
+            if (!ifs)
+                return NULL;
+
+            for (j = 0; j < n_ifs; j++) {
+                REQ(ch, list_iter);
+                ch = CHILD(ch, 0);
+                REQ(ch, list_if);
+                
+                list_for_expr = ast_for_expr(c, CHILD(ch, 1));
+                if (!list_for_expr)
+                    return NULL;
+                
+                asdl_seq_SET(ifs, j, list_for_expr);
+                if (NCH(ch) == 3)
+                    ch = CHILD(ch, 2);
+            }
+            /* on exit, must guarantee that ch is a list_for */
+            if (TYPE(ch) == list_iter)
+                ch = CHILD(ch, 0);
+            lc->ifs = ifs;
+        }
+        asdl_seq_SET(listcomps, i, lc);
+    }
+
+    return ListComp(elt, listcomps, LINENO(n), n->n_col_offset, c->c_arena);
+}
+
+/* Count the number of 'for' loops in a generator expression.
+
+   Helper for ast_for_genexp().
+*/
+
+static int
+count_gen_fors(struct compiling *c, const node *n)
+{
+    int n_fors = 0;
+    node *ch = CHILD(n, 1);
+
+ count_gen_for:
+    n_fors++;
+    REQ(ch, gen_for);
+    if (NCH(ch) == 5)
+        ch = CHILD(ch, 4);
+    else
+        return n_fors;
+ count_gen_iter:
+    REQ(ch, gen_iter);
+    ch = CHILD(ch, 0);
+    if (TYPE(ch) == gen_for)
+        goto count_gen_for;
+    else if (TYPE(ch) == gen_if) {
+        if (NCH(ch) == 3) {
+            ch = CHILD(ch, 2);
+            goto count_gen_iter;
+        }
+        else
+            return n_fors;
+    }
+    
+    /* Should never be reached */
+    PyErr_SetString(PyExc_SystemError,
+                    "logic error in count_gen_fors");
+    return -1;
+}
+
+/* Count the number of 'if' statements in a generator expression.
+
+   Helper for ast_for_genexp().
+*/
+
+static int
+count_gen_ifs(struct compiling *c, const node *n)
+{
+    int n_ifs = 0;
+
+    while (1) {
+        REQ(n, gen_iter);
+        if (TYPE(CHILD(n, 0)) == gen_for)
+            return n_ifs;
+        n = CHILD(n, 0);
+        REQ(n, gen_if);
+        n_ifs++;
+        if (NCH(n) == 2)
+            return n_ifs;
+        n = CHILD(n, 2);
+    }
+}
+
+/* TODO(jhylton): Combine with list comprehension code? */
+static expr_ty
+ast_for_genexp(struct compiling *c, const node *n)
+{
+    /* testlist_gexp: test ( gen_for | (',' test)* [','] )
+       argument: [test '='] test [gen_for]       # Really [keyword '='] test */
+    expr_ty elt;
+    asdl_seq *genexps;
+    int i, n_fors;
+    node *ch;
+    
+    assert(TYPE(n) == (testlist_gexp) || TYPE(n) == (argument));
+    assert(NCH(n) > 1);
+    
+    elt = ast_for_expr(c, CHILD(n, 0));
+    if (!elt)
+        return NULL;
+    
+    n_fors = count_gen_fors(c, n);
+    if (n_fors == -1)
+        return NULL;
+
+    genexps = asdl_seq_new(n_fors, c->c_arena);
+    if (!genexps)
+        return NULL;
+
+    ch = CHILD(n, 1);
+    for (i = 0; i < n_fors; i++) {
+        comprehension_ty ge;
+        asdl_seq *t;
+        expr_ty expression;
+        node *for_ch;
+        
+        REQ(ch, gen_for);
+        
+        for_ch = CHILD(ch, 1);
+        t = ast_for_exprlist(c, for_ch, Store);
+        if (!t)
+            return NULL;
+        expression = ast_for_expr(c, CHILD(ch, 3));
+        if (!expression)
+            return NULL;
+
+        /* Check the # of children rather than the length of t, since
+           (x for x, in ...) has 1 element in t, but still requires a Tuple. */
+        if (NCH(for_ch) == 1)
+            ge = comprehension((expr_ty)asdl_seq_GET(t, 0), expression,
+                               NULL, c->c_arena);
+        else
+            ge = comprehension(Tuple(t, Store, LINENO(ch), ch->n_col_offset,
+                                     c->c_arena),
+                               expression, NULL, c->c_arena);
+
+        if (!ge)
+            return NULL;
+
+        if (NCH(ch) == 5) {
+            int j, n_ifs;
+            asdl_seq *ifs;
+            
+            ch = CHILD(ch, 4);
+            n_ifs = count_gen_ifs(c, ch);
+            if (n_ifs == -1)
+                return NULL;
+
+            ifs = asdl_seq_new(n_ifs, c->c_arena);
+            if (!ifs)
+                return NULL;
+
+            for (j = 0; j < n_ifs; j++) {
+                REQ(ch, gen_iter);
+                ch = CHILD(ch, 0);
+                REQ(ch, gen_if);
+                
+                expression = ast_for_expr(c, CHILD(ch, 1));
+                if (!expression)
+                    return NULL;
+                asdl_seq_SET(ifs, j, expression);
+                if (NCH(ch) == 3)
+                    ch = CHILD(ch, 2);
+            }
+            /* on exit, must guarantee that ch is a gen_for */
+            if (TYPE(ch) == gen_iter)
+                ch = CHILD(ch, 0);
+            ge->ifs = ifs;
+        }
+        asdl_seq_SET(genexps, i, ge);
+    }
+    
+    return GeneratorExp(elt, genexps, LINENO(n), n->n_col_offset, c->c_arena);
+}
+
+static expr_ty
+ast_for_atom(struct compiling *c, const node *n)
+{
+    /* atom: '(' [yield_expr|testlist_gexp] ')' | '[' [listmaker] ']'
+       | '{' [dictmaker] '}' | '`' testlist '`' | NAME | NUMBER | STRING+
+    */
+    node *ch = CHILD(n, 0);
+    
+    switch (TYPE(ch)) {
+    case NAME: {
+        /* All names start in Load context, but may later be
+           changed. */
+        PyObject *name = NEW_IDENTIFIER(ch);
+        if (!name)
+            return NULL;
+        return Name(name, Load, LINENO(n), n->n_col_offset, c->c_arena);
+    }
+    case STRING: {
+        PyObject *str = parsestrplus(c, n);
+        if (!str) {
+#ifdef Py_USING_UNICODE
+            if (PyErr_ExceptionMatches(PyExc_UnicodeError)){
+                PyObject *type, *value, *tback, *errstr;
+                PyErr_Fetch(&type, &value, &tback);
+                errstr = PyObject_Str(value);
+                if (errstr) {
+                    char *s = "";
+                    char buf[128];
+                    s = PyString_AsString(errstr);
+                    PyOS_snprintf(buf, sizeof(buf), "(unicode error) %s", s);
+                    ast_error(n, buf);
+                    Py_DECREF(errstr);
+                } else {
+                    ast_error(n, "(unicode error) unknown error");
+                }
+                Py_DECREF(type);
+                Py_DECREF(value);
+                Py_XDECREF(tback);
+            }
+#endif
+            return NULL;
+        }
+        PyArena_AddPyObject(c->c_arena, str);
+        return Str(str, LINENO(n), n->n_col_offset, c->c_arena);
+    }
+    case NUMBER: {
+        PyObject *pynum = parsenumber(c, STR(ch));
+        if (!pynum)
+            return NULL;
+
+        PyArena_AddPyObject(c->c_arena, pynum);
+        return Num(pynum, LINENO(n), n->n_col_offset, c->c_arena);
+    }
+    case LPAR: /* some parenthesized expressions */
+        ch = CHILD(n, 1);
+        
+        if (TYPE(ch) == RPAR)
+            return Tuple(NULL, Load, LINENO(n), n->n_col_offset, c->c_arena);
+        
+        if (TYPE(ch) == yield_expr)
+            return ast_for_expr(c, ch);
+        
+        if ((NCH(ch) > 1) && (TYPE(CHILD(ch, 1)) == gen_for))
+            return ast_for_genexp(c, ch);
+        
+        return ast_for_testlist_gexp(c, ch);
+    case LSQB: /* list (or list comprehension) */
+        ch = CHILD(n, 1);
+        
+        if (TYPE(ch) == RSQB)
+            return List(NULL, Load, LINENO(n), n->n_col_offset, c->c_arena);
+        
+        REQ(ch, listmaker);
+        if (NCH(ch) == 1 || TYPE(CHILD(ch, 1)) == COMMA) {
+            asdl_seq *elts = seq_for_testlist(c, ch);
+            if (!elts)
+                return NULL;
+
+            return List(elts, Load, LINENO(n), n->n_col_offset, c->c_arena);
+        }
+        else
+            return ast_for_listcomp(c, ch);
+    case LBRACE: {
+        /* dictmaker: test ':' test (',' test ':' test)* [','] */
+        int i, size;
+        asdl_seq *keys, *values;
+        
+        ch = CHILD(n, 1);
+        size = (NCH(ch) + 1) / 4; /* +1 in case no trailing comma */
+        keys = asdl_seq_new(size, c->c_arena);
+        if (!keys)
+            return NULL;
+        
+        values = asdl_seq_new(size, c->c_arena);
+        if (!values)
+            return NULL;
+        
+        for (i = 0; i < NCH(ch); i += 4) {
+            expr_ty expression;
+            
+            expression = ast_for_expr(c, CHILD(ch, i));
+            if (!expression)
+                return NULL;
+
+            asdl_seq_SET(keys, i / 4, expression);
+
+            expression = ast_for_expr(c, CHILD(ch, i + 2));
+            if (!expression)
+                return NULL;
+
+            asdl_seq_SET(values, i / 4, expression);
+        }
+        return Dict(keys, values, LINENO(n), n->n_col_offset, c->c_arena);
+    }
+    case BACKQUOTE: { /* repr */
+        expr_ty expression;
+        if (Py_Py3kWarningFlag &&
+            !ast_warn(c, n, "backquote not supported in 3.x; use repr()"))
+            return NULL;
+        expression = ast_for_testlist(c, CHILD(n, 1));
+        if (!expression)
+            return NULL;
+
+        return Repr(expression, LINENO(n), n->n_col_offset, c->c_arena);
+    }
+    default:
+        PyErr_Format(PyExc_SystemError, "unhandled atom %d", TYPE(ch));
+        return NULL;
+    }
+}
+
+static slice_ty
+ast_for_slice(struct compiling *c, const node *n)
+{
+    node *ch;
+    expr_ty lower = NULL, upper = NULL, step = NULL;
+
+    REQ(n, subscript);
+
+    /*
+       subscript: '.' '.' '.' | test | [test] ':' [test] [sliceop]
+       sliceop: ':' [test]
+    */
+    ch = CHILD(n, 0);
+    if (TYPE(ch) == DOT)
+        return Ellipsis(c->c_arena);
+
+    if (NCH(n) == 1 && TYPE(ch) == test) {
+        /* 'step' variable hold no significance in terms of being used over
+           other vars */
+        step = ast_for_expr(c, ch); 
+        if (!step)
+            return NULL;
+            
+        return Index(step, c->c_arena);
+    }
+
+    if (TYPE(ch) == test) {
+        lower = ast_for_expr(c, ch);
+        if (!lower)
+            return NULL;
+    }
+
+    /* If there's an upper bound it's in the second or third position. */
+    if (TYPE(ch) == COLON) {
+        if (NCH(n) > 1) {
+            node *n2 = CHILD(n, 1);
+
+            if (TYPE(n2) == test) {
+                upper = ast_for_expr(c, n2);
+                if (!upper)
+                    return NULL;
+            }
+        }
+    } else if (NCH(n) > 2) {
+        node *n2 = CHILD(n, 2);
+
+        if (TYPE(n2) == test) {
+            upper = ast_for_expr(c, n2);
+            if (!upper)
+                return NULL;
+        }
+    }
+
+    ch = CHILD(n, NCH(n) - 1);
+    if (TYPE(ch) == sliceop) {
+        if (NCH(ch) == 1) {
+            /* No expression, so step is None */
+            ch = CHILD(ch, 0);
+            step = Name(new_identifier("None", c->c_arena), Load,
+                        LINENO(ch), ch->n_col_offset, c->c_arena);
+            if (!step)
+                return NULL;
+        } else {
+            ch = CHILD(ch, 1);
+            if (TYPE(ch) == test) {
+                step = ast_for_expr(c, ch);
+                if (!step)
+                    return NULL;
+            }
+        }
+    }
+
+    return Slice(lower, upper, step, c->c_arena);
+}
+
+static expr_ty
+ast_for_binop(struct compiling *c, const node *n)
+{
+        /* Must account for a sequence of expressions.
+           How should A op B op C by represented?  
+           BinOp(BinOp(A, op, B), op, C).
+        */
+
+        int i, nops;
+        expr_ty expr1, expr2, result;
+        operator_ty newoperator;
+
+        expr1 = ast_for_expr(c, CHILD(n, 0));
+        if (!expr1)
+            return NULL;
+
+        expr2 = ast_for_expr(c, CHILD(n, 2));
+        if (!expr2)
+            return NULL;
+
+        newoperator = get_operator(CHILD(n, 1));
+        if (!newoperator)
+            return NULL;
+
+        result = BinOp(expr1, newoperator, expr2, LINENO(n), n->n_col_offset,
+                       c->c_arena);
+        if (!result)
+            return NULL;
+
+        nops = (NCH(n) - 1) / 2;
+        for (i = 1; i < nops; i++) {
+                expr_ty tmp_result, tmp;
+                const node* next_oper = CHILD(n, i * 2 + 1);
+
+                newoperator = get_operator(next_oper);
+                if (!newoperator)
+                    return NULL;
+
+                tmp = ast_for_expr(c, CHILD(n, i * 2 + 2));
+                if (!tmp)
+                    return NULL;
+
+                tmp_result = BinOp(result, newoperator, tmp, 
+                                   LINENO(next_oper), next_oper->n_col_offset,
+                                   c->c_arena);
+                if (!tmp_result) 
+                        return NULL;
+                result = tmp_result;
+        }
+        return result;
+}
+
+static expr_ty
+ast_for_trailer(struct compiling *c, const node *n, expr_ty left_expr)
+{
+    /* trailer: '(' [arglist] ')' | '[' subscriptlist ']' | '.' NAME 
+       subscriptlist: subscript (',' subscript)* [',']
+       subscript: '.' '.' '.' | test | [test] ':' [test] [sliceop]
+     */
+    REQ(n, trailer);
+    if (TYPE(CHILD(n, 0)) == LPAR) {
+        if (NCH(n) == 2)
+            return Call(left_expr, NULL, NULL, NULL, NULL, LINENO(n),
+                        n->n_col_offset, c->c_arena);
+        else
+            return ast_for_call(c, CHILD(n, 1), left_expr);
+    }
+    else if (TYPE(CHILD(n, 0)) == DOT ) {
+        PyObject *attr_id = NEW_IDENTIFIER(CHILD(n, 1));
+        if (!attr_id)
+            return NULL;
+        return Attribute(left_expr, attr_id, Load,
+                         LINENO(n), n->n_col_offset, c->c_arena);
+    }
+    else {
+        REQ(CHILD(n, 0), LSQB);
+        REQ(CHILD(n, 2), RSQB);
+        n = CHILD(n, 1);
+        if (NCH(n) == 1) {
+            slice_ty slc = ast_for_slice(c, CHILD(n, 0));
+            if (!slc)
+                return NULL;
+            return Subscript(left_expr, slc, Load, LINENO(n), n->n_col_offset,
+                             c->c_arena);
+        }
+        else {
+            /* The grammar is ambiguous here. The ambiguity is resolved 
+               by treating the sequence as a tuple literal if there are
+               no slice features.
+            */
+            int j;
+            slice_ty slc;
+            expr_ty e;
+            bool simple = true;
+            asdl_seq *slices, *elts;
+            slices = asdl_seq_new((NCH(n) + 1) / 2, c->c_arena);
+            if (!slices)
+                return NULL;
+            for (j = 0; j < NCH(n); j += 2) {
+                slc = ast_for_slice(c, CHILD(n, j));
+                if (!slc)
+                    return NULL;
+                if (slc->kind != Index_kind)
+                    simple = false;
+                asdl_seq_SET(slices, j / 2, slc);
+            }
+            if (!simple) {
+                return Subscript(left_expr, ExtSlice(slices, c->c_arena),
+                                 Load, LINENO(n), n->n_col_offset, c->c_arena);
+            }
+            /* extract Index values and put them in a Tuple */
+            elts = asdl_seq_new(asdl_seq_LEN(slices), c->c_arena);
+            if (!elts)
+                return NULL;
+            for (j = 0; j < asdl_seq_LEN(slices); ++j) {
+                slc = (slice_ty)asdl_seq_GET(slices, j);
+                assert(slc->kind == Index_kind  && slc->v.Index.value);
+                asdl_seq_SET(elts, j, slc->v.Index.value);
+            }
+            e = Tuple(elts, Load, LINENO(n), n->n_col_offset, c->c_arena);
+            if (!e)
+                return NULL;
+            return Subscript(left_expr, Index(e, c->c_arena),
+                             Load, LINENO(n), n->n_col_offset, c->c_arena);
+        }
+    }
+}
+
+static expr_ty
+ast_for_factor(struct compiling *c, const node *n)
+{
+    node *pfactor, *ppower, *patom, *pnum;
+    expr_ty expression;
+
+    /* If the unary - operator is applied to a constant, don't generate
+       a UNARY_NEGATIVE opcode.  Just store the approriate value as a
+       constant.  The peephole optimizer already does something like
+       this but it doesn't handle the case where the constant is
+       (sys.maxint - 1).  In that case, we want a PyIntObject, not a
+       PyLongObject.
+    */
+    if (TYPE(CHILD(n, 0)) == MINUS &&
+        NCH(n) == 2 &&
+        TYPE((pfactor = CHILD(n, 1))) == factor &&
+        NCH(pfactor) == 1 &&
+        TYPE((ppower = CHILD(pfactor, 0))) == power &&
+        NCH(ppower) == 1 &&
+        TYPE((patom = CHILD(ppower, 0))) == atom &&
+        TYPE((pnum = CHILD(patom, 0))) == NUMBER) {
+        char *s = PyObject_MALLOC(strlen(STR(pnum)) + 2);
+        if (s == NULL)
+            return NULL;
+        s[0] = '-';
+        strcpy(s + 1, STR(pnum));
+        PyObject_FREE(STR(pnum));
+        STR(pnum) = s;
+        return ast_for_atom(c, patom);
+    }
+
+    expression = ast_for_expr(c, CHILD(n, 1));
+    if (!expression)
+        return NULL;
+
+    switch (TYPE(CHILD(n, 0))) {
+        case PLUS:
+            return UnaryOp(UAdd, expression, LINENO(n), n->n_col_offset,
+                           c->c_arena);
+        case MINUS:
+            return UnaryOp(USub, expression, LINENO(n), n->n_col_offset,
+                           c->c_arena);
+        case TILDE:
+            return UnaryOp(Invert, expression, LINENO(n),
+                           n->n_col_offset, c->c_arena);
+    }
+    PyErr_Format(PyExc_SystemError, "unhandled factor: %d",
+                 TYPE(CHILD(n, 0)));
+    return NULL;
+}
+
+static expr_ty
+ast_for_power(struct compiling *c, const node *n)
+{
+    /* power: atom trailer* ('**' factor)*
+     */
+    int i;
+    expr_ty e, tmp;
+    REQ(n, power);
+    e = ast_for_atom(c, CHILD(n, 0));
+    if (!e)
+        return NULL;
+    if (NCH(n) == 1)
+        return e;
+    for (i = 1; i < NCH(n); i++) {
+        node *ch = CHILD(n, i);
+        if (TYPE(ch) != trailer)
+            break;
+        tmp = ast_for_trailer(c, ch, e);
+        if (!tmp)
+            return NULL;
+        tmp->lineno = e->lineno;
+        tmp->col_offset = e->col_offset;
+        e = tmp;
+    }
+    if (TYPE(CHILD(n, NCH(n) - 1)) == factor) {
+        expr_ty f = ast_for_expr(c, CHILD(n, NCH(n) - 1));
+        if (!f)
+            return NULL;
+        tmp = BinOp(e, Pow, f, LINENO(n), n->n_col_offset, c->c_arena);
+        if (!tmp)
+            return NULL;
+        e = tmp;
+    }
+    return e;
+}
+
+/* Do not name a variable 'expr'!  Will cause a compile error.
+*/
+
+static expr_ty
+ast_for_expr(struct compiling *c, const node *n)
+{
+    /* handle the full range of simple expressions
+       test: or_test ['if' or_test 'else' test] | lambdef
+       or_test: and_test ('or' and_test)* 
+       and_test: not_test ('and' not_test)*
+       not_test: 'not' not_test | comparison
+       comparison: expr (comp_op expr)*
+       expr: xor_expr ('|' xor_expr)*
+       xor_expr: and_expr ('^' and_expr)*
+       and_expr: shift_expr ('&' shift_expr)*
+       shift_expr: arith_expr (('<<'|'>>') arith_expr)*
+       arith_expr: term (('+'|'-') term)*
+       term: factor (('*'|'/'|'%'|'//') factor)*
+       factor: ('+'|'-'|'~') factor | power
+       power: atom trailer* ('**' factor)*
+
+       As well as modified versions that exist for backward compatibility,
+       to explicitly allow:
+       [ x for x in lambda: 0, lambda: 1 ]
+       (which would be ambiguous without these extra rules)
+       
+       old_test: or_test | old_lambdef
+       old_lambdef: 'lambda' [vararglist] ':' old_test
+
+    */
+
+    asdl_seq *seq;
+    int i;
+
+ loop:
+    switch (TYPE(n)) {
+        case test:
+        case old_test:
+            if (TYPE(CHILD(n, 0)) == lambdef ||
+                TYPE(CHILD(n, 0)) == old_lambdef)
+                return ast_for_lambdef(c, CHILD(n, 0));
+            else if (NCH(n) > 1)
+                return ast_for_ifexpr(c, n);
+            /* Fallthrough */
+        case or_test:
+        case and_test:
+            if (NCH(n) == 1) {
+                n = CHILD(n, 0);
+                goto loop;
+            }
+            seq = asdl_seq_new((NCH(n) + 1) / 2, c->c_arena);
+            if (!seq)
+                return NULL;
+            for (i = 0; i < NCH(n); i += 2) {
+                expr_ty e = ast_for_expr(c, CHILD(n, i));
+                if (!e)
+                    return NULL;
+                asdl_seq_SET(seq, i / 2, e);
+            }
+            if (!strcmp(STR(CHILD(n, 1)), "and"))
+                return BoolOp(And, seq, LINENO(n), n->n_col_offset,
+                              c->c_arena);
+            assert(!strcmp(STR(CHILD(n, 1)), "or"));
+            return BoolOp(Or, seq, LINENO(n), n->n_col_offset, c->c_arena);
+        case not_test:
+            if (NCH(n) == 1) {
+                n = CHILD(n, 0);
+                goto loop;
+            }
+            else {
+                expr_ty expression = ast_for_expr(c, CHILD(n, 1));
+                if (!expression)
+                    return NULL;
+
+                return UnaryOp(Not, expression, LINENO(n), n->n_col_offset,
+                               c->c_arena);
+            }
+        case comparison:
+            if (NCH(n) == 1) {
+                n = CHILD(n, 0);
+                goto loop;
+            }
+            else {
+                expr_ty expression;
+                asdl_int_seq *ops;
+                asdl_seq *cmps;
+                ops = asdl_int_seq_new(NCH(n) / 2, c->c_arena);
+                if (!ops)
+                    return NULL;
+                cmps = asdl_seq_new(NCH(n) / 2, c->c_arena);
+                if (!cmps) {
+                    return NULL;
+                }
+                for (i = 1; i < NCH(n); i += 2) {
+                    cmpop_ty newoperator;
+
+                    newoperator = ast_for_comp_op(c, CHILD(n, i));
+                    if (!newoperator) {
+                        return NULL;
+                    }
+
+                    expression = ast_for_expr(c, CHILD(n, i + 1));
+                    if (!expression) {
+                        return NULL;
+                    }
+                        
+                    asdl_seq_SET(ops, i / 2, newoperator);
+                    asdl_seq_SET(cmps, i / 2, expression);
+                }
+                expression = ast_for_expr(c, CHILD(n, 0));
+                if (!expression) {
+                    return NULL;
+                }
+                    
+                return Compare(expression, ops, cmps, LINENO(n),
+                               n->n_col_offset, c->c_arena);
+            }
+            break;
+
+        /* The next five cases all handle BinOps.  The main body of code
+           is the same in each case, but the switch turned inside out to
+           reuse the code for each type of operator.
+         */
+        case expr:
+        case xor_expr:
+        case and_expr:
+        case shift_expr:
+        case arith_expr:
+        case term:
+            if (NCH(n) == 1) {
+                n = CHILD(n, 0);
+                goto loop;
+            }
+            return ast_for_binop(c, n);
+        case yield_expr: {
+            expr_ty exp = NULL;
+            if (NCH(n) == 2) {
+                exp = ast_for_testlist(c, CHILD(n, 1));
+                if (!exp)
+                    return NULL;
+            }
+            return Yield(exp, LINENO(n), n->n_col_offset, c->c_arena);
+        }
+        case factor:
+            if (NCH(n) == 1) {
+                n = CHILD(n, 0);
+                goto loop;
+            }
+            return ast_for_factor(c, n);
+        case power:
+            return ast_for_power(c, n);
+        default:
+            PyErr_Format(PyExc_SystemError, "unhandled expr: %d", TYPE(n));
+            return NULL;
+    }
+    /* should never get here unless if error is set */
+    return NULL;
+}
+
+static expr_ty
+ast_for_call(struct compiling *c, const node *n, expr_ty func)
+{
+    /*
+      arglist: (argument ',')* (argument [',']| '*' test [',' '**' test]
+               | '**' test)
+      argument: [test '='] test [gen_for]        # Really [keyword '='] test
+    */
+
+    int i, nargs, nkeywords, ngens;
+    asdl_seq *args;
+    asdl_seq *keywords;
+    expr_ty vararg = NULL, kwarg = NULL;
+
+    REQ(n, arglist);
+
+    nargs = 0;
+    nkeywords = 0;
+    ngens = 0;
+    for (i = 0; i < NCH(n); i++) {
+        node *ch = CHILD(n, i);
+        if (TYPE(ch) == argument) {
+            if (NCH(ch) == 1)
+                nargs++;
+            else if (TYPE(CHILD(ch, 1)) == gen_for)
+                ngens++;
+            else
+                nkeywords++;
+        }
+    }
+    if (ngens > 1 || (ngens && (nargs || nkeywords))) {
+        ast_error(n, "Generator expression must be parenthesized "
+                  "if not sole argument");
+        return NULL;
+    }
+
+    if (nargs + nkeywords + ngens > 255) {
+      ast_error(n, "more than 255 arguments");
+      return NULL;
+    }
+
+    args = asdl_seq_new(nargs + ngens, c->c_arena);
+    if (!args)
+        return NULL;
+    keywords = asdl_seq_new(nkeywords, c->c_arena);
+    if (!keywords)
+        return NULL;
+    nargs = 0;
+    nkeywords = 0;
+    for (i = 0; i < NCH(n); i++) {
+        node *ch = CHILD(n, i);
+        if (TYPE(ch) == argument) {
+            expr_ty e;
+            if (NCH(ch) == 1) {
+                if (nkeywords) {
+                    ast_error(CHILD(ch, 0),
+                              "non-keyword arg after keyword arg");
+                    return NULL;
+                }
+                if (vararg) {
+                    ast_error(CHILD(ch, 0),
+                              "only named arguments may follow *expression");
+                    return NULL;
+                }
+                e = ast_for_expr(c, CHILD(ch, 0));
+                if (!e)
+                    return NULL;
+                asdl_seq_SET(args, nargs++, e);
+            }  
+            else if (TYPE(CHILD(ch, 1)) == gen_for) {
+                e = ast_for_genexp(c, ch);
+                if (!e)
+                    return NULL;
+                asdl_seq_SET(args, nargs++, e);
+            }
+            else {
+                keyword_ty kw;
+                identifier key;
+                int k;
+                char *tmp;
+
+                /* CHILD(ch, 0) is test, but must be an identifier? */ 
+                e = ast_for_expr(c, CHILD(ch, 0));
+                if (!e)
+                    return NULL;
+                /* f(lambda x: x[0] = 3) ends up getting parsed with
+                 * LHS test = lambda x: x[0], and RHS test = 3.
+                 * SF bug 132313 points out that complaining about a keyword
+                 * then is very confusing.
+                 */
+                if (e->kind == Lambda_kind) {
+                    ast_error(CHILD(ch, 0),
+                              "lambda cannot contain assignment");
+                    return NULL;
+                } else if (e->kind != Name_kind) {
+                    ast_error(CHILD(ch, 0), "keyword can't be an expression");
+                    return NULL;
+                }
+                key = e->v.Name.id;
+                if (!forbidden_check(c, CHILD(ch, 0), PyBytes_AS_STRING(key)))
+                    return NULL;
+                for (k = 0; k < nkeywords; k++) {
+                    tmp = PyString_AS_STRING(
+                        ((keyword_ty)asdl_seq_GET(keywords, k))->arg);
+                    if (!strcmp(tmp, PyString_AS_STRING(key))) {
+                        ast_error(CHILD(ch, 0), "keyword argument repeated");
+                        return NULL;
+                    }
+                }
+                e = ast_for_expr(c, CHILD(ch, 2));
+                if (!e)
+                    return NULL;
+                kw = keyword(key, e, c->c_arena);
+                if (!kw)
+                    return NULL;
+                asdl_seq_SET(keywords, nkeywords++, kw);
+            }
+        }
+        else if (TYPE(ch) == STAR) {
+            vararg = ast_for_expr(c, CHILD(n, i+1));
+            if (!vararg)
+                return NULL;
+            i++;
+        }
+        else if (TYPE(ch) == DOUBLESTAR) {
+            kwarg = ast_for_expr(c, CHILD(n, i+1));
+            if (!kwarg)
+                return NULL;
+            i++;
+        }
+    }
+
+    return Call(func, args, keywords, vararg, kwarg, func->lineno,
+                func->col_offset, c->c_arena);
+}
+
+static expr_ty
+ast_for_testlist(struct compiling *c, const node* n)
+{
+    /* testlist_gexp: test (',' test)* [','] */
+    /* testlist: test (',' test)* [','] */
+    /* testlist_safe: test (',' test)+ [','] */
+    /* testlist1: test (',' test)* */
+    assert(NCH(n) > 0);
+    if (TYPE(n) == testlist_gexp) {
+        if (NCH(n) > 1)
+            assert(TYPE(CHILD(n, 1)) != gen_for);
+    }
+    else {
+        assert(TYPE(n) == testlist ||
+               TYPE(n) == testlist_safe ||
+               TYPE(n) == testlist1);
+    }
+    if (NCH(n) == 1)
+        return ast_for_expr(c, CHILD(n, 0));
+    else {
+        asdl_seq *tmp = seq_for_testlist(c, n);
+        if (!tmp)
+            return NULL;
+        return Tuple(tmp, Load, LINENO(n), n->n_col_offset, c->c_arena);
+    }
+}
+
+static expr_ty
+ast_for_testlist_gexp(struct compiling *c, const node* n)
+{
+    /* testlist_gexp: test ( gen_for | (',' test)* [','] ) */
+    /* argument: test [ gen_for ] */
+    assert(TYPE(n) == testlist_gexp || TYPE(n) == argument);
+    if (NCH(n) > 1 && TYPE(CHILD(n, 1)) == gen_for)
+        return ast_for_genexp(c, n);
+    return ast_for_testlist(c, n);
+}
+
+/* like ast_for_testlist() but returns a sequence */
+static asdl_seq*
+ast_for_class_bases(struct compiling *c, const node* n)
+{
+    /* testlist: test (',' test)* [','] */
+    assert(NCH(n) > 0);
+    REQ(n, testlist);
+    if (NCH(n) == 1) {
+        expr_ty base;
+        asdl_seq *bases = asdl_seq_new(1, c->c_arena);
+        if (!bases)
+            return NULL;
+        base = ast_for_expr(c, CHILD(n, 0));
+        if (!base)
+            return NULL;
+        asdl_seq_SET(bases, 0, base);
+        return bases;
+    }
+
+    return seq_for_testlist(c, n);
+}
+
+static stmt_ty
+ast_for_expr_stmt(struct compiling *c, const node *n)
+{
+    REQ(n, expr_stmt);
+    /* expr_stmt: testlist (augassign (yield_expr|testlist) 
+                | ('=' (yield_expr|testlist))*)
+       testlist: test (',' test)* [',']
+       augassign: '+=' | '-=' | '*=' | '/=' | '%=' | '&=' | '|=' | '^='
+                | '<<=' | '>>=' | '**=' | '//='
+       test: ... here starts the operator precendence dance
+     */
+
+    if (NCH(n) == 1) {
+        expr_ty e = ast_for_testlist(c, CHILD(n, 0));
+        if (!e)
+            return NULL;
+
+        return Expr(e, LINENO(n), n->n_col_offset, c->c_arena);
+    }
+    else if (TYPE(CHILD(n, 1)) == augassign) {
+        expr_ty expr1, expr2;
+        operator_ty newoperator;
+        node *ch = CHILD(n, 0);
+
+        expr1 = ast_for_testlist(c, ch);
+        if (!expr1)
+            return NULL;
+        /* TODO(nas): Remove duplicated error checks (set_context does it) */
+        switch (expr1->kind) {
+            case GeneratorExp_kind:
+                ast_error(ch, "augmented assignment to generator "
+                          "expression not possible");
+                return NULL;
+            case Yield_kind:
+                ast_error(ch, "augmented assignment to yield "
+                          "expression not possible");
+                return NULL;
+            case Name_kind: {
+                const char *var_name = PyBytes_AS_STRING(expr1->v.Name.id);
+                if ((var_name[0] == 'N' || var_name[0] == 'T' || var_name[0] == 'F') &&
+                    !forbidden_check(c, ch, var_name))
+                    return NULL;
+                break;
+            }
+            case Attribute_kind:
+            case Subscript_kind:
+                break;
+            default:
+                ast_error(ch, "illegal expression for augmented "
+                          "assignment");
+                return NULL;
+        }
+        if(!set_context(c, expr1, Store, ch))
+            return NULL;
+
+        ch = CHILD(n, 2);
+        if (TYPE(ch) == testlist)
+            expr2 = ast_for_testlist(c, ch);
+        else
+            expr2 = ast_for_expr(c, ch);
+        if (!expr2)
+            return NULL;
+
+        newoperator = ast_for_augassign(c, CHILD(n, 1));
+        if (!newoperator)
+            return NULL;
+
+        return AugAssign(expr1, newoperator, expr2, LINENO(n), n->n_col_offset,
+                         c->c_arena);
+    }
+    else {
+        int i;
+        asdl_seq *targets;
+        node *value;
+        expr_ty expression;
+
+        /* a normal assignment */
+        REQ(CHILD(n, 1), EQUAL);
+        targets = asdl_seq_new(NCH(n) / 2, c->c_arena);
+        if (!targets)
+            return NULL;
+        for (i = 0; i < NCH(n) - 2; i += 2) {
+            expr_ty e;
+            node *ch = CHILD(n, i);
+            if (TYPE(ch) == yield_expr) {
+                ast_error(ch, "assignment to yield expression not possible");
+                return NULL;
+            }
+            e = ast_for_testlist(c, ch);
+
+            /* set context to assign */
+            if (!e) 
+                return NULL;
+
+            if (!set_context(c, e, Store, CHILD(n, i)))
+                return NULL;
+
+            asdl_seq_SET(targets, i / 2, e);
+        }
+        value = CHILD(n, NCH(n) - 1);
+        if (TYPE(value) == testlist)
+            expression = ast_for_testlist(c, value);
+        else
+            expression = ast_for_expr(c, value);
+        if (!expression)
+            return NULL;
+        return Assign(targets, expression, LINENO(n), n->n_col_offset,
+                      c->c_arena);
+    }
+}
+
+static stmt_ty
+ast_for_print_stmt(struct compiling *c, const node *n)
+{
+    /* print_stmt: 'print' ( [ test (',' test)* [','] ]
+                             | '>>' test [ (',' test)+ [','] ] )
+     */
+    expr_ty dest = NULL, expression;
+    asdl_seq *seq;
+    bool nl;
+    int i, j, start = 1;
+
+    REQ(n, print_stmt);
+    if (NCH(n) >= 2 && TYPE(CHILD(n, 1)) == RIGHTSHIFT) {
+        dest = ast_for_expr(c, CHILD(n, 2));
+        if (!dest)
+            return NULL;
+            start = 4;
+    }
+    seq = asdl_seq_new((NCH(n) + 1 - start) / 2, c->c_arena);
+    if (!seq)
+        return NULL;
+    for (i = start, j = 0; i < NCH(n); i += 2, ++j) {
+        expression = ast_for_expr(c, CHILD(n, i));
+        if (!expression)
+            return NULL;
+        asdl_seq_SET(seq, j, expression);
+    }
+    nl = (TYPE(CHILD(n, NCH(n) - 1)) == COMMA) ? false : true;
+    return Print(dest, seq, nl, LINENO(n), n->n_col_offset, c->c_arena);
+}
+
+static asdl_seq *
+ast_for_exprlist(struct compiling *c, const node *n, expr_context_ty context)
+{
+    asdl_seq *seq;
+    int i;
+    expr_ty e;
+
+    REQ(n, exprlist);
+
+    seq = asdl_seq_new((NCH(n) + 1) / 2, c->c_arena);
+    if (!seq)
+        return NULL;
+    for (i = 0; i < NCH(n); i += 2) {
+        e = ast_for_expr(c, CHILD(n, i));
+        if (!e)
+            return NULL;
+        asdl_seq_SET(seq, i / 2, e);
+        if (context && !set_context(c, e, context, CHILD(n, i)))
+            return NULL;
+    }
+    return seq;
+}
+
+static stmt_ty
+ast_for_del_stmt(struct compiling *c, const node *n)
+{
+    asdl_seq *expr_list;
+    
+    /* del_stmt: 'del' exprlist */
+    REQ(n, del_stmt);
+
+    expr_list = ast_for_exprlist(c, CHILD(n, 1), Del);
+    if (!expr_list)
+        return NULL;
+    return Delete(expr_list, LINENO(n), n->n_col_offset, c->c_arena);
+}
+
+static stmt_ty
+ast_for_flow_stmt(struct compiling *c, const node *n)
+{
+    /*
+      flow_stmt: break_stmt | continue_stmt | return_stmt | raise_stmt
+                 | yield_stmt
+      break_stmt: 'break'
+      continue_stmt: 'continue'
+      return_stmt: 'return' [testlist]
+      yield_stmt: yield_expr
+      yield_expr: 'yield' testlist
+      raise_stmt: 'raise' [test [',' test [',' test]]]
+    */
+    node *ch;
+
+    REQ(n, flow_stmt);
+    ch = CHILD(n, 0);
+    switch (TYPE(ch)) {
+        case break_stmt:
+            return Break(LINENO(n), n->n_col_offset, c->c_arena);
+        case continue_stmt:
+            return Continue(LINENO(n), n->n_col_offset, c->c_arena);
+        case yield_stmt: { /* will reduce to yield_expr */
+            expr_ty exp = ast_for_expr(c, CHILD(ch, 0));
+            if (!exp)
+                return NULL;
+            return Expr(exp, LINENO(n), n->n_col_offset, c->c_arena);
+        }
+        case return_stmt:
+            if (NCH(ch) == 1)
+                return Return(NULL, LINENO(n), n->n_col_offset, c->c_arena);
+            else {
+                expr_ty expression = ast_for_testlist(c, CHILD(ch, 1));
+                if (!expression)
+                    return NULL;
+                return Return(expression, LINENO(n), n->n_col_offset,
+                              c->c_arena);
+            }
+        case raise_stmt:
+            if (NCH(ch) == 1)
+                return Raise(NULL, NULL, NULL, LINENO(n), n->n_col_offset,
+                             c->c_arena);
+            else if (NCH(ch) == 2) {
+                expr_ty expression = ast_for_expr(c, CHILD(ch, 1));
+                if (!expression)
+                    return NULL;
+                return Raise(expression, NULL, NULL, LINENO(n),
+                             n->n_col_offset, c->c_arena);
+            }
+            else if (NCH(ch) == 4) {
+                expr_ty expr1, expr2;
+
+                expr1 = ast_for_expr(c, CHILD(ch, 1));
+                if (!expr1)
+                    return NULL;
+                expr2 = ast_for_expr(c, CHILD(ch, 3));
+                if (!expr2)
+                    return NULL;
+
+                return Raise(expr1, expr2, NULL, LINENO(n), n->n_col_offset,
+                             c->c_arena);
+            }
+            else if (NCH(ch) == 6) {
+                expr_ty expr1, expr2, expr3;
+
+                expr1 = ast_for_expr(c, CHILD(ch, 1));
+                if (!expr1)
+                    return NULL;
+                expr2 = ast_for_expr(c, CHILD(ch, 3));
+                if (!expr2)
+                    return NULL;
+                expr3 = ast_for_expr(c, CHILD(ch, 5));
+                if (!expr3)
+                    return NULL;
+                    
+                return Raise(expr1, expr2, expr3, LINENO(n), n->n_col_offset,
+                             c->c_arena);
+            }
+        default:
+            PyErr_Format(PyExc_SystemError,
+                         "unexpected flow_stmt: %d", TYPE(ch));
+            return NULL;
+    }
+
+    PyErr_SetString(PyExc_SystemError, "unhandled flow statement");
+    return NULL;
+}
+
+static alias_ty
+alias_for_import_name(struct compiling *c, const node *n)
+{
+    /*
+      import_as_name: NAME ['as' NAME]
+      dotted_as_name: dotted_name ['as' NAME]
+      dotted_name: NAME ('.' NAME)*
+    */
+    PyObject *str, *name;
+
+ loop:
+    switch (TYPE(n)) {
+        case import_as_name:
+            str = NULL;
+            if (NCH(n) == 3) {
+                str = NEW_IDENTIFIER(CHILD(n, 2));
+                if (!str)
+                    return NULL;
+            }
+            name = NEW_IDENTIFIER(CHILD(n, 0));
+            if (!name)
+                return NULL;
+            return alias(name, str, c->c_arena);
+        case dotted_as_name:
+            if (NCH(n) == 1) {
+                n = CHILD(n, 0);
+                goto loop;
+            }
+            else {
+                alias_ty a = alias_for_import_name(c, CHILD(n, 0));
+                if (!a)
+                    return NULL;
+                assert(!a->asname);
+                a->asname = NEW_IDENTIFIER(CHILD(n, 2));
+                if (!a->asname)
+                    return NULL;
+                return a;
+            }
+            break;
+        case dotted_name:
+            if (NCH(n) == 1) {
+                name = NEW_IDENTIFIER(CHILD(n, 0));
+                if (!name)
+                    return NULL;
+                return alias(name, NULL, c->c_arena);
+            }
+            else {
+                /* Create a string of the form "a.b.c" */
+                int i;
+                size_t len;
+                char *s;
+
+                len = 0;
+                for (i = 0; i < NCH(n); i += 2)
+                    /* length of string plus one for the dot */
+                    len += strlen(STR(CHILD(n, i))) + 1;
+                len--; /* the last name doesn't have a dot */
+                str = PyString_FromStringAndSize(NULL, len);
+                if (!str)
+                    return NULL;
+                s = PyString_AS_STRING(str);
+                if (!s)
+                    return NULL;
+                for (i = 0; i < NCH(n); i += 2) {
+                    char *sch = STR(CHILD(n, i));
+                    strcpy(s, STR(CHILD(n, i)));
+                    s += strlen(sch);
+                    *s++ = '.';
+                }
+                --s;
+                *s = '\0';
+                PyString_InternInPlace(&str);
+                PyArena_AddPyObject(c->c_arena, str);
+                return alias(str, NULL, c->c_arena);
+            }
+            break;
+        case STAR:
+            str = PyString_InternFromString("*");
+            PyArena_AddPyObject(c->c_arena, str);
+            return alias(str, NULL, c->c_arena);
+        default:
+            PyErr_Format(PyExc_SystemError,
+                         "unexpected import name: %d", TYPE(n));
+            return NULL;
+    }
+
+    PyErr_SetString(PyExc_SystemError, "unhandled import name condition");
+    return NULL;
+}
+
+static stmt_ty
+ast_for_import_stmt(struct compiling *c, const node *n)
+{
+    /*
+      import_stmt: import_name | import_from
+      import_name: 'import' dotted_as_names
+      import_from: 'from' ('.'* dotted_name | '.') 'import'
+                          ('*' | '(' import_as_names ')' | import_as_names)
+    */
+    int lineno;
+    int col_offset;
+    int i;
+    asdl_seq *aliases;
+
+    REQ(n, import_stmt);
+    lineno = LINENO(n);
+    col_offset = n->n_col_offset;
+    n = CHILD(n, 0);
+    if (TYPE(n) == import_name) {
+        n = CHILD(n, 1);
+        REQ(n, dotted_as_names);
+        aliases = asdl_seq_new((NCH(n) + 1) / 2, c->c_arena);
+        if (!aliases)
+            return NULL;
+        for (i = 0; i < NCH(n); i += 2) {
+            alias_ty import_alias = alias_for_import_name(c, CHILD(n, i));
+            if (!import_alias)
+                return NULL;
+            asdl_seq_SET(aliases, i / 2, import_alias);
+        }
+        return Import(aliases, lineno, col_offset, c->c_arena);
+    }
+    else if (TYPE(n) == import_from) {
+        int n_children;
+        int idx, ndots = 0;
+        alias_ty mod = NULL;
+        identifier modname;
+        
+       /* Count the number of dots (for relative imports) and check for the
+          optional module name */
+        for (idx = 1; idx < NCH(n); idx++) {
+            if (TYPE(CHILD(n, idx)) == dotted_name) {
+                mod = alias_for_import_name(c, CHILD(n, idx));
+                idx++;
+                break;
+            } else if (TYPE(CHILD(n, idx)) != DOT) {
+                break;
+            }
+            ndots++;
+        }
+        idx++; /* skip over the 'import' keyword */
+        switch (TYPE(CHILD(n, idx))) {
+        case STAR:
+            /* from ... import * */
+            n = CHILD(n, idx);
+            n_children = 1;
+            break;
+        case LPAR:
+            /* from ... import (x, y, z) */
+            n = CHILD(n, idx + 1);
+            n_children = NCH(n);
+            break;
+        case import_as_names:
+            /* from ... import x, y, z */
+            n = CHILD(n, idx);
+            n_children = NCH(n);
+            if (n_children % 2 == 0) {
+                ast_error(n, "trailing comma not allowed without"
+                             " surrounding parentheses");
+                return NULL;
+            }
+            break;
+        default:
+            ast_error(n, "Unexpected node-type in from-import");
+            return NULL;
+        }
+
+        aliases = asdl_seq_new((n_children + 1) / 2, c->c_arena);
+        if (!aliases)
+            return NULL;
+
+        /* handle "from ... import *" special b/c there's no children */
+        if (TYPE(n) == STAR) {
+            alias_ty import_alias = alias_for_import_name(c, n);
+            if (!import_alias)
+                return NULL;
+                asdl_seq_SET(aliases, 0, import_alias);
+        }
+        else {
+            for (i = 0; i < NCH(n); i += 2) {
+                alias_ty import_alias = alias_for_import_name(c, CHILD(n, i));
+                if (!import_alias)
+                    return NULL;
+                    asdl_seq_SET(aliases, i / 2, import_alias);
+            }
+        }
+        if (mod != NULL)
+            modname = mod->name;
+        else
+            modname = new_identifier("", c->c_arena);
+        return ImportFrom(modname, aliases, ndots, lineno, col_offset,
+                          c->c_arena);
+    }
+    PyErr_Format(PyExc_SystemError,
+                 "unknown import statement: starts with command '%s'",
+                 STR(CHILD(n, 0)));
+    return NULL;
+}
+
+static stmt_ty
+ast_for_global_stmt(struct compiling *c, const node *n)
+{
+    /* global_stmt: 'global' NAME (',' NAME)* */
+    identifier name;
+    asdl_seq *s;
+    int i;
+
+    REQ(n, global_stmt);
+    s = asdl_seq_new(NCH(n) / 2, c->c_arena);
+    if (!s)
+        return NULL;
+    for (i = 1; i < NCH(n); i += 2) {
+        name = NEW_IDENTIFIER(CHILD(n, i));
+        if (!name)
+            return NULL;
+        asdl_seq_SET(s, i / 2, name);
+    }
+    return Global(s, LINENO(n), n->n_col_offset, c->c_arena);
+}
+
+static stmt_ty
+ast_for_exec_stmt(struct compiling *c, const node *n)
+{
+    expr_ty expr1, globals = NULL, locals = NULL;
+    int n_children = NCH(n);
+    if (n_children != 2 && n_children != 4 && n_children != 6) {
+        PyErr_Format(PyExc_SystemError,
+                     "poorly formed 'exec' statement: %d parts to statement",
+                     n_children);
+        return NULL;
+    }
+
+    /* exec_stmt: 'exec' expr ['in' test [',' test]] */
+    REQ(n, exec_stmt);
+    expr1 = ast_for_expr(c, CHILD(n, 1));
+    if (!expr1)
+        return NULL;
+    if (n_children >= 4) {
+        globals = ast_for_expr(c, CHILD(n, 3));
+        if (!globals)
+            return NULL;
+    }
+    if (n_children == 6) {
+        locals = ast_for_expr(c, CHILD(n, 5));
+        if (!locals)
+            return NULL;
+    }
+
+    return Exec(expr1, globals, locals, LINENO(n), n->n_col_offset,
+                c->c_arena);
+}
+
+static stmt_ty
+ast_for_assert_stmt(struct compiling *c, const node *n)
+{
+    /* assert_stmt: 'assert' test [',' test] */
+    REQ(n, assert_stmt);
+    if (NCH(n) == 2) {
+        expr_ty expression = ast_for_expr(c, CHILD(n, 1));
+        if (!expression)
+            return NULL;
+        return Assert(expression, NULL, LINENO(n), n->n_col_offset,
+                      c->c_arena);
+    }
+    else if (NCH(n) == 4) {
+        expr_ty expr1, expr2;
+
+        expr1 = ast_for_expr(c, CHILD(n, 1));
+        if (!expr1)
+            return NULL;
+        expr2 = ast_for_expr(c, CHILD(n, 3));
+        if (!expr2)
+            return NULL;
+            
+        return Assert(expr1, expr2, LINENO(n), n->n_col_offset, c->c_arena);
+    }
+    PyErr_Format(PyExc_SystemError,
+                 "improper number of parts to 'assert' statement: %d",
+                 NCH(n));
+    return NULL;
+}
+
+static asdl_seq *
+ast_for_suite(struct compiling *c, const node *n)
+{
+    /* suite: simple_stmt | NEWLINE INDENT stmt+ DEDENT */
+    asdl_seq *seq;
+    stmt_ty s;
+    int i, total, num, end, pos = 0;
+    node *ch;
+
+    REQ(n, suite);
+
+    total = num_stmts(n);
+    seq = asdl_seq_new(total, c->c_arena);
+    if (!seq)
+        return NULL;
+    if (TYPE(CHILD(n, 0)) == simple_stmt) {
+        n = CHILD(n, 0);
+        /* simple_stmt always ends with a NEWLINE,
+           and may have a trailing SEMI 
+        */
+        end = NCH(n) - 1;
+        if (TYPE(CHILD(n, end - 1)) == SEMI)
+            end--;
+        /* loop by 2 to skip semi-colons */
+        for (i = 0; i < end; i += 2) {
+            ch = CHILD(n, i);
+            s = ast_for_stmt(c, ch);
+            if (!s)
+                return NULL;
+            asdl_seq_SET(seq, pos++, s);
+        }
+    }
+    else {
+        for (i = 2; i < (NCH(n) - 1); i++) {
+            ch = CHILD(n, i);
+            REQ(ch, stmt);
+            num = num_stmts(ch);
+            if (num == 1) {
+                /* small_stmt or compound_stmt with only one child */
+                s = ast_for_stmt(c, ch);
+                if (!s)
+                    return NULL;
+                asdl_seq_SET(seq, pos++, s);
+            }
+            else {
+                int j;
+                ch = CHILD(ch, 0);
+                REQ(ch, simple_stmt);
+                for (j = 0; j < NCH(ch); j += 2) {
+                    /* statement terminates with a semi-colon ';' */
+                    if (NCH(CHILD(ch, j)) == 0) {
+                        assert((j + 1) == NCH(ch));
+                        break;
+                    }
+                    s = ast_for_stmt(c, CHILD(ch, j));
+                    if (!s)
+                        return NULL;
+                    asdl_seq_SET(seq, pos++, s);
+                }
+            }
+        }
+    }
+    assert(pos == seq->size);
+    return seq;
+}
+
+static stmt_ty
+ast_for_if_stmt(struct compiling *c, const node *n)
+{
+    /* if_stmt: 'if' test ':' suite ('elif' test ':' suite)*
+       ['else' ':' suite]
+    */
+    char *s;
+
+    REQ(n, if_stmt);
+
+    if (NCH(n) == 4) {
+        expr_ty expression;
+        asdl_seq *suite_seq;
+
+        expression = ast_for_expr(c, CHILD(n, 1));
+        if (!expression)
+            return NULL;
+        suite_seq = ast_for_suite(c, CHILD(n, 3)); 
+        if (!suite_seq)
+            return NULL;
+            
+        return If(expression, suite_seq, NULL, LINENO(n), n->n_col_offset,
+                  c->c_arena);
+    }
+
+    s = STR(CHILD(n, 4));
+    /* s[2], the third character in the string, will be
+       's' for el_s_e, or
+       'i' for el_i_f
+    */
+    if (s[2] == 's') {
+        expr_ty expression;
+        asdl_seq *seq1, *seq2;
+
+        expression = ast_for_expr(c, CHILD(n, 1));
+        if (!expression)
+            return NULL;
+        seq1 = ast_for_suite(c, CHILD(n, 3));
+        if (!seq1)
+            return NULL;
+        seq2 = ast_for_suite(c, CHILD(n, 6));
+        if (!seq2)
+            return NULL;
+
+        return If(expression, seq1, seq2, LINENO(n), n->n_col_offset,
+                  c->c_arena);
+    }
+    else if (s[2] == 'i') {
+        int i, n_elif, has_else = 0;
+        expr_ty expression;
+        asdl_seq *suite_seq;
+        asdl_seq *orelse = NULL;
+        n_elif = NCH(n) - 4;
+        /* must reference the child n_elif+1 since 'else' token is third,
+           not fourth, child from the end. */
+        if (TYPE(CHILD(n, (n_elif + 1))) == NAME
+            && STR(CHILD(n, (n_elif + 1)))[2] == 's') {
+            has_else = 1;
+            n_elif -= 3;
+        }
+        n_elif /= 4;
+
+        if (has_else) {
+            asdl_seq *suite_seq2;
+
+            orelse = asdl_seq_new(1, c->c_arena);
+            if (!orelse)
+                return NULL;
+            expression = ast_for_expr(c, CHILD(n, NCH(n) - 6));
+            if (!expression)
+                return NULL;
+            suite_seq = ast_for_suite(c, CHILD(n, NCH(n) - 4));
+            if (!suite_seq)
+                return NULL;
+            suite_seq2 = ast_for_suite(c, CHILD(n, NCH(n) - 1));
+            if (!suite_seq2)
+                return NULL;
+
+            asdl_seq_SET(orelse, 0, 
+                         If(expression, suite_seq, suite_seq2, 
+                            LINENO(CHILD(n, NCH(n) - 6)),
+                            CHILD(n, NCH(n) - 6)->n_col_offset,
+                            c->c_arena));
+            /* the just-created orelse handled the last elif */
+            n_elif--;
+        }
+
+        for (i = 0; i < n_elif; i++) {
+            int off = 5 + (n_elif - i - 1) * 4;
+            asdl_seq *newobj = asdl_seq_new(1, c->c_arena);
+            if (!newobj)
+                return NULL;
+            expression = ast_for_expr(c, CHILD(n, off));
+            if (!expression)
+                return NULL;
+            suite_seq = ast_for_suite(c, CHILD(n, off + 2));
+            if (!suite_seq)
+                return NULL;
+
+            asdl_seq_SET(newobj, 0,
+                         If(expression, suite_seq, orelse, 
+                            LINENO(CHILD(n, off)),
+                            CHILD(n, off)->n_col_offset, c->c_arena));
+            orelse = newobj;
+        }
+        expression = ast_for_expr(c, CHILD(n, 1));
+        if (!expression)
+            return NULL;
+        suite_seq = ast_for_suite(c, CHILD(n, 3));
+        if (!suite_seq)
+            return NULL;
+        return If(expression, suite_seq, orelse,
+                  LINENO(n), n->n_col_offset, c->c_arena);
+    }
+
+    PyErr_Format(PyExc_SystemError,
+                 "unexpected token in 'if' statement: %s", s);
+    return NULL;
+}
+
+static stmt_ty
+ast_for_while_stmt(struct compiling *c, const node *n)
+{
+    /* while_stmt: 'while' test ':' suite ['else' ':' suite] */
+    REQ(n, while_stmt);
+
+    if (NCH(n) == 4) {
+        expr_ty expression;
+        asdl_seq *suite_seq;
+
+        expression = ast_for_expr(c, CHILD(n, 1));
+        if (!expression)
+            return NULL;
+        suite_seq = ast_for_suite(c, CHILD(n, 3));
+        if (!suite_seq)
+            return NULL;
+        return While(expression, suite_seq, NULL, LINENO(n), n->n_col_offset,
+                     c->c_arena);
+    }
+    else if (NCH(n) == 7) {
+        expr_ty expression;
+        asdl_seq *seq1, *seq2;
+
+        expression = ast_for_expr(c, CHILD(n, 1));
+        if (!expression)
+            return NULL;
+        seq1 = ast_for_suite(c, CHILD(n, 3));
+        if (!seq1)
+            return NULL;
+        seq2 = ast_for_suite(c, CHILD(n, 6));
+        if (!seq2)
+            return NULL;
+
+        return While(expression, seq1, seq2, LINENO(n), n->n_col_offset,
+                     c->c_arena);
+    }
+
+    PyErr_Format(PyExc_SystemError,
+                 "wrong number of tokens for 'while' statement: %d",
+                 NCH(n));
+    return NULL;
+}
+
+static stmt_ty
+ast_for_for_stmt(struct compiling *c, const node *n)
+{
+    asdl_seq *_target, *seq = NULL, *suite_seq;
+    expr_ty expression;
+    expr_ty target;
+    const node *node_target;
+    /* for_stmt: 'for' exprlist 'in' testlist ':' suite ['else' ':' suite] */
+    REQ(n, for_stmt);
+
+    if (NCH(n) == 9) {
+        seq = ast_for_suite(c, CHILD(n, 8));
+        if (!seq)
+            return NULL;
+    }
+
+    node_target = CHILD(n, 1);
+    _target = ast_for_exprlist(c, node_target, Store);
+    if (!_target)
+        return NULL;
+    /* Check the # of children rather than the length of _target, since
+       for x, in ... has 1 element in _target, but still requires a Tuple. */
+    if (NCH(node_target) == 1)
+        target = (expr_ty)asdl_seq_GET(_target, 0);
+    else
+        target = Tuple(_target, Store, LINENO(n), n->n_col_offset, c->c_arena);
+
+    expression = ast_for_testlist(c, CHILD(n, 3));
+    if (!expression)
+        return NULL;
+    suite_seq = ast_for_suite(c, CHILD(n, 5));
+    if (!suite_seq)
+        return NULL;
+
+    return For(target, expression, suite_seq, seq, LINENO(n), n->n_col_offset,
+               c->c_arena);
+}
+
+static excepthandler_ty
+ast_for_except_clause(struct compiling *c, const node *exc, node *body)
+{
+    /* except_clause: 'except' [test [(',' | 'as') test]] */
+    REQ(exc, except_clause);
+    REQ(body, suite);
+
+    if (NCH(exc) == 1) {
+        asdl_seq *suite_seq = ast_for_suite(c, body);
+        if (!suite_seq)
+            return NULL;
+
+        return ExceptHandler(NULL, NULL, suite_seq, LINENO(exc),
+                             exc->n_col_offset, c->c_arena);
+    }
+    else if (NCH(exc) == 2) {
+        expr_ty expression;
+        asdl_seq *suite_seq;
+
+        expression = ast_for_expr(c, CHILD(exc, 1));
+        if (!expression)
+            return NULL;
+        suite_seq = ast_for_suite(c, body);
+        if (!suite_seq)
+            return NULL;
+
+        return ExceptHandler(expression, NULL, suite_seq, LINENO(exc),
+                             exc->n_col_offset, c->c_arena);
+    }
+    else if (NCH(exc) == 4) {
+        asdl_seq *suite_seq;
+        expr_ty expression;
+        expr_ty e = ast_for_expr(c, CHILD(exc, 3));
+        if (!e)
+            return NULL;
+        if (!set_context(c, e, Store, CHILD(exc, 3)))
+            return NULL;
+        expression = ast_for_expr(c, CHILD(exc, 1));
+        if (!expression)
+            return NULL;
+        suite_seq = ast_for_suite(c, body);
+        if (!suite_seq)
+            return NULL;
+
+        return ExceptHandler(expression, e, suite_seq, LINENO(exc),
+                             exc->n_col_offset, c->c_arena);
+    }
+
+    PyErr_Format(PyExc_SystemError,
+                 "wrong number of children for 'except' clause: %d",
+                 NCH(exc));
+    return NULL;
+}
+
+static stmt_ty
+ast_for_try_stmt(struct compiling *c, const node *n)
+{
+    const int nch = NCH(n);
+    int n_except = (nch - 3)/3;
+    asdl_seq *body, *orelse = NULL, *finally = NULL;
+
+    REQ(n, try_stmt);
+
+    body = ast_for_suite(c, CHILD(n, 2));
+    if (body == NULL)
+        return NULL;
+
+    if (TYPE(CHILD(n, nch - 3)) == NAME) {
+        if (strcmp(STR(CHILD(n, nch - 3)), "finally") == 0) {
+            if (nch >= 9 && TYPE(CHILD(n, nch - 6)) == NAME) {
+                /* we can assume it's an "else",
+                   because nch >= 9 for try-else-finally and
+                   it would otherwise have a type of except_clause */
+                orelse = ast_for_suite(c, CHILD(n, nch - 4));
+                if (orelse == NULL)
+                    return NULL;
+                n_except--;
+            }
+
+            finally = ast_for_suite(c, CHILD(n, nch - 1));
+            if (finally == NULL)
+                return NULL;
+            n_except--;
+        }
+        else {
+            /* we can assume it's an "else",
+               otherwise it would have a type of except_clause */
+            orelse = ast_for_suite(c, CHILD(n, nch - 1));
+            if (orelse == NULL)
+                return NULL;
+            n_except--;
+        }
+    }
+    else if (TYPE(CHILD(n, nch - 3)) != except_clause) {
+        ast_error(n, "malformed 'try' statement");
+        return NULL;
+    }
+    
+    if (n_except > 0) {
+        int i;
+        stmt_ty except_st;
+        /* process except statements to create a try ... except */
+        asdl_seq *handlers = asdl_seq_new(n_except, c->c_arena);
+        if (handlers == NULL)
+            return NULL;
+
+        for (i = 0; i < n_except; i++) {
+            excepthandler_ty e = ast_for_except_clause(c, CHILD(n, 3 + i * 3),
+                                                       CHILD(n, 5 + i * 3));
+            if (!e)
+                return NULL;
+            asdl_seq_SET(handlers, i, e);
+        }
+
+        except_st = TryExcept(body, handlers, orelse, LINENO(n),
+                              n->n_col_offset, c->c_arena);
+        if (!finally)
+            return except_st;
+
+        /* if a 'finally' is present too, we nest the TryExcept within a
+           TryFinally to emulate try ... except ... finally */
+        body = asdl_seq_new(1, c->c_arena);
+        if (body == NULL)
+            return NULL;
+        asdl_seq_SET(body, 0, except_st);
+    }
+
+    /* must be a try ... finally (except clauses are in body, if any exist) */
+    assert(finally != NULL);
+    return TryFinally(body, finally, LINENO(n), n->n_col_offset, c->c_arena);
+}
+
+static expr_ty
+ast_for_with_var(struct compiling *c, const node *n)
+{
+    REQ(n, with_var);
+    return ast_for_expr(c, CHILD(n, 1));
+}
+
+/* with_stmt: 'with' test [ with_var ] ':' suite */
+static stmt_ty
+ast_for_with_stmt(struct compiling *c, const node *n)
+{
+    expr_ty context_expr, optional_vars = NULL;
+    int suite_index = 3;    /* skip 'with', test, and ':' */
+    asdl_seq *suite_seq;
+
+    assert(TYPE(n) == with_stmt);
+    context_expr = ast_for_expr(c, CHILD(n, 1));
+    if (!context_expr)
+        return NULL;
+    if (TYPE(CHILD(n, 2)) == with_var) {
+        optional_vars = ast_for_with_var(c, CHILD(n, 2));
+
+        if (!optional_vars) {
+            return NULL;
+        }
+        if (!set_context(c, optional_vars, Store, n)) {
+            return NULL;
+        }
+        suite_index = 4;
+    }
+
+    suite_seq = ast_for_suite(c, CHILD(n, suite_index));
+    if (!suite_seq) {
+        return NULL;
+    }
+    return With(context_expr, optional_vars, suite_seq, LINENO(n), 
+                n->n_col_offset, c->c_arena);
+}
+
+static stmt_ty
+ast_for_classdef(struct compiling *c, const node *n, asdl_seq *decorator_seq)
+{
+    /* classdef: 'class' NAME ['(' testlist ')'] ':' suite */
+    PyObject *classname;
+    asdl_seq *bases, *s;
+    
+    REQ(n, classdef);
+
+    if (!forbidden_check(c, n, STR(CHILD(n, 1))))
+            return NULL;
+
+    if (NCH(n) == 4) {
+        s = ast_for_suite(c, CHILD(n, 3));
+        if (!s)
+            return NULL;
+        classname = NEW_IDENTIFIER(CHILD(n, 1));
+        if (!classname)
+            return NULL;
+        return ClassDef(classname, NULL, s, decorator_seq, LINENO(n),
+                        n->n_col_offset, c->c_arena);
+    }
+    /* check for empty base list */
+    if (TYPE(CHILD(n,3)) == RPAR) {
+        s = ast_for_suite(c, CHILD(n,5));
+        if (!s)
+            return NULL;
+        classname = NEW_IDENTIFIER(CHILD(n, 1));
+        if (!classname)
+            return NULL;
+        return ClassDef(classname, NULL, s, decorator_seq, LINENO(n),
+                        n->n_col_offset, c->c_arena);
+    }
+
+    /* else handle the base class list */
+    bases = ast_for_class_bases(c, CHILD(n, 3));
+    if (!bases)
+        return NULL;
+
+    s = ast_for_suite(c, CHILD(n, 6));
+    if (!s)
+        return NULL;
+    classname = NEW_IDENTIFIER(CHILD(n, 1));
+    if (!classname)
+        return NULL;
+    return ClassDef(classname, bases, s, decorator_seq,
+                    LINENO(n), n->n_col_offset, c->c_arena);
+}
+
+static stmt_ty
+ast_for_stmt(struct compiling *c, const node *n)
+{
+    if (TYPE(n) == stmt) {
+        assert(NCH(n) == 1);
+        n = CHILD(n, 0);
+    }
+    if (TYPE(n) == simple_stmt) {
+        assert(num_stmts(n) == 1);
+        n = CHILD(n, 0);
+    }
+    if (TYPE(n) == small_stmt) {
+        REQ(n, small_stmt);
+        n = CHILD(n, 0);
+        /* small_stmt: expr_stmt | print_stmt  | del_stmt | pass_stmt
+                     | flow_stmt | import_stmt | global_stmt | exec_stmt
+                     | assert_stmt
+        */
+        switch (TYPE(n)) {
+            case expr_stmt:
+                return ast_for_expr_stmt(c, n);
+            case print_stmt:
+                return ast_for_print_stmt(c, n);
+            case del_stmt:
+                return ast_for_del_stmt(c, n);
+            case pass_stmt:
+                return Pass(LINENO(n), n->n_col_offset, c->c_arena);
+            case flow_stmt:
+                return ast_for_flow_stmt(c, n);
+            case import_stmt:
+                return ast_for_import_stmt(c, n);
+            case global_stmt:
+                return ast_for_global_stmt(c, n);
+            case exec_stmt:
+                return ast_for_exec_stmt(c, n);
+            case assert_stmt:
+                return ast_for_assert_stmt(c, n);
+            default:
+                PyErr_Format(PyExc_SystemError,
+                             "unhandled small_stmt: TYPE=%d NCH=%d\n",
+                             TYPE(n), NCH(n));
+                return NULL;
+        }
+    }
+    else {
+        /* compound_stmt: if_stmt | while_stmt | for_stmt | try_stmt
+                        | funcdef | classdef | decorated
+        */
+        node *ch = CHILD(n, 0);
+        REQ(n, compound_stmt);
+        switch (TYPE(ch)) {
+            case if_stmt:
+                return ast_for_if_stmt(c, ch);
+            case while_stmt:
+                return ast_for_while_stmt(c, ch);
+            case for_stmt:
+                return ast_for_for_stmt(c, ch);
+            case try_stmt:
+                return ast_for_try_stmt(c, ch);
+            case with_stmt:
+                return ast_for_with_stmt(c, ch);
+            case funcdef:
+                return ast_for_funcdef(c, ch, NULL);
+            case classdef:
+                return ast_for_classdef(c, ch, NULL);
+	    case decorated:
+	        return ast_for_decorated(c, ch);
+            default:
+                PyErr_Format(PyExc_SystemError,
+                             "unhandled small_stmt: TYPE=%d NCH=%d\n",
+                             TYPE(n), NCH(n));
+                return NULL;
+        }
+    }
+}
+
+static PyObject *
+parsenumber(struct compiling *c, const char *s)
+{
+        const char *end;
+        long x;
+        double dx;
+#ifndef WITHOUT_COMPLEX
+        Py_complex complex;
+        int imflag;
+#endif
+
+        errno = 0;
+        end = s + strlen(s) - 1;
+#ifndef WITHOUT_COMPLEX
+        imflag = *end == 'j' || *end == 'J';
+#endif
+        if (*end == 'l' || *end == 'L')
+                return PyLong_FromString((char *)s, (char **)0, 0);
+        x = PyOS_strtol((char *)s, (char **)&end, 0);
+        if (*end == '\0') {
+                if (errno != 0)
+                        return PyLong_FromString((char *)s, (char **)0, 0);
+                return PyInt_FromLong(x);
+        }
+        /* XXX Huge floats may silently fail */
+#ifndef WITHOUT_COMPLEX
+        if (imflag) {
+                complex.real = 0.;
+                PyFPE_START_PROTECT("atof", return 0)
+                complex.imag = PyOS_ascii_atof(s);
+                PyFPE_END_PROTECT(complex)
+                return PyComplex_FromCComplex(complex);
+        }
+        else
+#endif
+        {
+                PyFPE_START_PROTECT("atof", return 0)
+                dx = PyOS_ascii_atof(s);
+                PyFPE_END_PROTECT(dx)
+                return PyFloat_FromDouble(dx);
+        }
+}
+
+static PyObject *
+decode_utf8(struct compiling *c, const char **sPtr, const char *end, char* encoding)
+{
+#ifndef Py_USING_UNICODE
+        Py_FatalError("decode_utf8 should not be called in this build.");
+        return NULL;
+#else
+        PyObject *u, *v;
+        char *s, *t;
+        t = s = (char *)*sPtr;
+        /* while (s < end && *s != '\\') s++; */ /* inefficient for u".." */
+        while (s < end && (*s & 0x80)) s++;
+        *sPtr = s;
+        u = PyUnicode_DecodeUTF8(t, s - t, NULL);
+        if (u == NULL)
+                return NULL;
+        v = PyUnicode_AsEncodedString(u, encoding, NULL);
+        Py_DECREF(u);
+        return v;
+#endif
+}
+
+#ifdef Py_USING_UNICODE
+static PyObject *
+decode_unicode(struct compiling *c, const char *s, size_t len, int rawmode, const char *encoding)
+{
+        PyObject *v, *u;
+        char *buf;
+        char *p;
+        const char *end;
+        if (encoding == NULL) {
+                buf = (char *)s;
+                u = NULL;
+        } else if (strcmp(encoding, "iso-8859-1") == 0) {
+                buf = (char *)s;
+                u = NULL;
+        } else {
+                /* check for integer overflow */
+                if (len > PY_SIZE_MAX / 4)
+                        return NULL;
+                /* "\XX" may become "\u005c\uHHLL" (12 bytes) */
+                u = PyString_FromStringAndSize((char *)NULL, len * 4);
+                if (u == NULL)
+                        return NULL;
+                p = buf = PyString_AsString(u);
+                end = s + len;
+                while (s < end) {
+                        if (*s == '\\') {
+                                *p++ = *s++;
+                                if (*s & 0x80) {
+                                        strcpy(p, "u005c");
+                                        p += 5;
+                                }
+                        }
+                        if (*s & 0x80) { /* XXX inefficient */
+                                PyObject *w;
+                                char *r;
+                                Py_ssize_t rn, i;
+                                w = decode_utf8(c, &s, end, "utf-16-be");
+                                if (w == NULL) {
+                                        Py_DECREF(u);
+                                        return NULL;
+                                }
+                                r = PyString_AsString(w);
+                                rn = PyString_Size(w);
+                                assert(rn % 2 == 0);
+                                for (i = 0; i < rn; i += 2) {
+                                        sprintf(p, "\\u%02x%02x",
+                                                r[i + 0] & 0xFF,
+                                                r[i + 1] & 0xFF);
+                                        p += 6;
+                                }
+                                Py_DECREF(w);
+                        } else {
+                                *p++ = *s++;
+                        }
+                }
+                len = p - buf;
+                s = buf;
+        }
+        if (rawmode)
+                v = PyUnicode_DecodeRawUnicodeEscape(s, len, NULL);
+        else
+                v = PyUnicode_DecodeUnicodeEscape(s, len, NULL);
+        Py_XDECREF(u);
+        return v;
+}
+#endif
+
+/* s is a Python string literal, including the bracketing quote characters,
+ * and r &/or u prefixes (if any), and embedded escape sequences (if any).
+ * parsestr parses it, and returns the decoded Python string object.
+ */
+static PyObject *
+parsestr(struct compiling *c, const char *s)
+{
+        size_t len;
+        int quote = Py_CHARMASK(*s);
+        int rawmode = 0;
+        int need_encoding;
+        int unicode = c->c_future_unicode;
+
+        if (isalpha(quote) || quote == '_') {
+                if (quote == 'u' || quote == 'U') {
+                        quote = *++s;
+                        unicode = 1;
+                }
+                if (quote == 'b' || quote == 'B') {
+                        quote = *++s;
+                        unicode = 0;
+                }
+                if (quote == 'r' || quote == 'R') {
+                        quote = *++s;
+                        rawmode = 1;
+                }
+        }
+        if (quote != '\'' && quote != '\"') {
+                PyErr_BadInternalCall();
+                return NULL;
+        }
+        s++;
+        len = strlen(s);
+        if (len > INT_MAX) {
+                PyErr_SetString(PyExc_OverflowError, 
+                                "string to parse is too long");
+                return NULL;
+        }
+        if (s[--len] != quote) {
+                PyErr_BadInternalCall();
+                return NULL;
+        }
+        if (len >= 4 && s[0] == quote && s[1] == quote) {
+                s += 2;
+                len -= 2;
+                if (s[--len] != quote || s[--len] != quote) {
+                        PyErr_BadInternalCall();
+                        return NULL;
+                }
+        }
+#ifdef Py_USING_UNICODE
+        if (unicode || Py_UnicodeFlag) {
+                return decode_unicode(c, s, len, rawmode, c->c_encoding);
+        }
+#endif
+        need_encoding = (c->c_encoding != NULL &&
+                         strcmp(c->c_encoding, "utf-8") != 0 &&
+                         strcmp(c->c_encoding, "iso-8859-1") != 0);
+        if (rawmode || strchr(s, '\\') == NULL) {
+                if (need_encoding) {
+#ifndef Py_USING_UNICODE
+                        /* This should not happen - we never see any other
+                           encoding. */
+                        Py_FatalError(
+                            "cannot deal with encodings in this build.");
+#else
+                        PyObject *v, *u = PyUnicode_DecodeUTF8(s, len, NULL);
+                        if (u == NULL)
+                                return NULL;
+                        v = PyUnicode_AsEncodedString(u, c->c_encoding, NULL);
+                        Py_DECREF(u);
+                        return v;
+#endif
+                } else {
+                        return PyString_FromStringAndSize(s, len);
+                }
+        }
+
+        return PyString_DecodeEscape(s, len, NULL, unicode,
+                                     need_encoding ? c->c_encoding : NULL);
+}
+
+/* Build a Python string object out of a STRING atom.  This takes care of
+ * compile-time literal catenation, calling parsestr() on each piece, and
+ * pasting the intermediate results together.
+ */
+static PyObject *
+parsestrplus(struct compiling *c, const node *n)
+{
+        PyObject *v;
+        int i;
+        REQ(CHILD(n, 0), STRING);
+        if ((v = parsestr(c, STR(CHILD(n, 0)))) != NULL) {
+                /* String literal concatenation */
+                for (i = 1; i < NCH(n); i++) {
+                        PyObject *s;
+                        s = parsestr(c, STR(CHILD(n, i)));
+                        if (s == NULL)
+                                goto onError;
+                        if (PyString_Check(v) && PyString_Check(s)) {
+                                PyString_ConcatAndDel(&v, s);
+                                if (v == NULL)
+                                    goto onError;
+                        }
+#ifdef Py_USING_UNICODE
+                        else {
+                                PyObject *temp = PyUnicode_Concat(v, s);
+                                Py_DECREF(s);
+                                Py_DECREF(v);
+                                v = temp;
+                                if (v == NULL)
+                                    goto onError;
+                        }
+#endif
+                }
+        }
+        return v;
+
+ onError:
+        Py_XDECREF(v);
+        return NULL;
+}