util/qlalr/examples/lambda/main.cpp
changeset 0 1918ee327afb
child 4 3b1da2848fc7
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/util/qlalr/examples/lambda/main.cpp	Mon Jan 11 14:00:40 2010 +0000
@@ -0,0 +1,199 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QLALR module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights.  These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "lambda.h"
+
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include "parser_table_p.h"
+
+class Parser: protected parser_table
+{
+public:
+    union Value {
+      int ival;
+      // ### more...
+    };
+
+public:
+    Parser();
+    ~Parser();
+
+    bool parse();
+
+protected:
+    inline void reallocateStack();
+
+    inline Value &sym(int index)
+    { return sym_stack [tos + index - 1]; }
+
+    int nextToken();
+    void consumeRule(int ruleno);
+
+protected:
+    int tos;
+    int stack_size;
+    Value *sym_stack;
+    int *state_stack;
+    int current_char;
+    unsigned in_tag: 1;
+};
+
+inline void Parser::reallocateStack()
+{
+    if (! stack_size)
+        stack_size = 128;
+    else
+        stack_size <<= 1;
+
+    sym_stack = reinterpret_cast<Value*> (::realloc(sym_stack, stack_size * sizeof(Value)));
+    state_stack = reinterpret_cast<int*> (::realloc(state_stack, stack_size * sizeof(int)));
+}
+
+Parser::Parser():
+    tos(0),
+    stack_size(0),
+    sym_stack(0),
+    state_stack(0)
+{
+}
+
+Parser::~Parser()
+{
+    if (stack_size) {
+        ::free(sym_stack);
+        ::free(state_stack);
+    }
+}
+
+bool Parser::parse()
+{
+  const int INITIAL_STATE = 0;
+
+  current_char = 0;
+  in_tag = 0;
+
+  int yytoken = -1;
+  reallocateStack();
+
+  tos = 0;
+  state_stack[++tos] = INITIAL_STATE;
+
+  while (true)
+    {
+      if (yytoken == -1 && - TERMINAL_COUNT != action_index [state_stack [tos]])
+        yytoken = nextToken();
+
+      int act = t_action (state_stack [tos], yytoken);
+
+      if (act == ACCEPT_STATE) {
+        return true;
+      }
+
+      else if (act > 0)
+        {
+          if (++tos == stack_size)
+            reallocateStack();
+
+          sym_stack [tos].ival = current_char; // ### save the token value here
+          state_stack [tos] = act;
+          yytoken = -1;
+        }
+
+      else if (act < 0)
+        {
+          int r = - act - 1;
+
+          tos -= rhs [r];
+          act = state_stack [tos++];
+          consumeRule (r);
+          state_stack [tos] = nt_action (act, lhs [r] - TERMINAL_COUNT);
+        }
+
+      else
+        break;
+    }
+
+    return false;
+}
+
+
+int Parser::nextToken()
+{
+    static int tokens[] = { ID, ID, ID, EOF_SYMBOL };
+    static int *tk = tokens;
+
+    return *tk++;
+}
+
+void Parser::consumeRule(int ruleno)
+{
+    switch (ruleno) {
+    case Symbol:
+        printf("symbol\n");
+        break;
+    case SubExpression:
+        printf("sub-expr\n");
+        break;
+    case Appl:
+        printf("appl\n");
+        break;
+    case Abstr:
+        printf("abstr\n");
+        break;
+    }
+}
+
+/////////////////////////////
+// entry point
+/////////////////////////////
+int main()
+{
+    Parser parser;
+
+    if (parser.parse())
+        printf ("OK\n");
+    else
+        printf ("KO\n");
+}
+
+