"""Tokenization help for Python programs.

generate_tokens(readline) is a generator that breaks a stream of

text into Python tokens.  It accepts a readline-like method which is called

repeatedly to get the next line of input (or "" for EOF).  It generates

5-tuples with these members:

    the token type (see token.py)

    the token (a string)

    the starting (row, column) indices of the token (a 2-tuple of ints)

    the ending (row, column) indices of the token (a 2-tuple of ints)

    the original line (string)

It is designed to match the working of the Python tokenizer exactly, except

that it produces COMMENT tokens for comments and gives type OP for all

operators

Older entry points

    tokenize_loop(readline, tokeneater)

    tokenize(readline, tokeneater=printtoken)

are the same, except instead of generating tokens, tokeneater is a callback

function to which the 5 fields described above are passed as 5 arguments,

each time a new token is found."""

__author__ = 'Ka-Ping Yee <ping@lfw.org>'

__credits__ = \

    'GvR, ESR, Tim Peters, Thomas Wouters, Fred Drake, Skip Montanaro'

import string, re

from token import *

import token

__all__ = [x for x in dir(token) if x[0] != '_'] + ["COMMENT", "tokenize",

           "generate_tokens", "NL", "untokenize"]

del x

del token

COMMENT = N_TOKENS

tok_name[COMMENT] = 'COMMENT'

NL = N_TOKENS + 1

tok_name[NL] = 'NL'

N_TOKENS += 2

def group(*choices): return '(' + '|'.join(choices) + ')'

def any(*choices): return group(*choices) + '*'

def maybe(*choices): return group(*choices) + '?'

Whitespace = r'[ \f\t]*'

Comment = r'#[^\r\n]*'

Ignore = Whitespace + any(r'\\\r?\n' + Whitespace) + maybe(Comment)

Name = r'[a-zA-Z_]\w*'

Hexnumber = r'0[xX][\da-fA-F]*[lL]?'

Octnumber = r'0[0-7]*[lL]?'

Decnumber = r'[1-9]\d*[lL]?'

Intnumber = group(Hexnumber, Octnumber, Decnumber)

Exponent = r'[eE][-+]?\d+'

Pointfloat = group(r'\d+\.\d*', r'\.\d+') + maybe(Exponent)

Expfloat = r'\d+' + Exponent

Floatnumber = group(Pointfloat, Expfloat)

Imagnumber = group(r'\d+[jJ]', Floatnumber + r'[jJ]')

Number = group(Imagnumber, Floatnumber, Intnumber)

# Tail end of ' string.

Single = r"[^'\\]*(?:\\.[^'\\]*)*'"

# Tail end of " string.

Double = r'[^"\\]*(?:\\.[^"\\]*)*"'

# Tail end of ''' string.

Single3 = r"[^'\\]*(?:(?:\\.|'(?!''))[^'\\]*)*'''"

# Tail end of """ string.

Double3 = r'[^"\\]*(?:(?:\\.|"(?!""))[^"\\]*)*"""'

Triple = group("[uU]?[rR]?'''", '[uU]?[rR]?"""')

# Single-line ' or " string.

String = group(r"[uU]?[rR]?'[^\n'\\]*(?:\\.[^\n'\\]*)*'",

               r'[uU]?[rR]?"[^\n"\\]*(?:\\.[^\n"\\]*)*"')

# Because of leftmost-then-longest match semantics, be sure to put the

# longest operators first (e.g., if = came before ==, == would get

# recognized as two instances of =).

Operator = group(r"\*\*=?", r">>=?", r"<<=?", r"<>", r"!=",

                 r"//=?",

                 r"[+\-*/%&|^=<>]=?",

                 r"~")

Bracket = '[][(){}]'

Special = group(r'\r?\n', r'[:;.,`@]')

Funny = group(Operator, Bracket, Special)

PlainToken = group(Number, Funny, String, Name)

Token = Ignore + PlainToken

# First (or only) line of ' or " string.

ContStr = group(r"[uU]?[rR]?'[^\n'\\]*(?:\\.[^\n'\\]*)*" +

                group("'", r'\\\r?\n'),

                r'[uU]?[rR]?"[^\n"\\]*(?:\\.[^\n"\\]*)*' +

                group('"', r'\\\r?\n'))

PseudoExtras = group(r'\\\r?\n', Comment, Triple)

PseudoToken = Whitespace + group(PseudoExtras, Number, Funny, ContStr, Name)

tokenprog, pseudoprog, single3prog, double3prog = map(

    re.compile, (Token, PseudoToken, Single3, Double3))

endprogs = {"'": re.compile(Single), '"': re.compile(Double),

            "'''": single3prog, '"""': double3prog,

            "r'''": single3prog, 'r"""': double3prog,

            "u'''": single3prog, 'u"""': double3prog,

            "ur'''": single3prog, 'ur"""': double3prog,

            "R'''": single3prog, 'R"""': double3prog,

            "U'''": single3prog, 'U"""': double3prog,

            "uR'''": single3prog, 'uR"""': double3prog,

            "Ur'''": single3prog, 'Ur"""': double3prog,

            "UR'''": single3prog, 'UR"""': double3prog,

            'r': None, 'R': None, 'u': None, 'U': None}

triple_quoted = {}

for t in ("'''", '"""',

          "r'''", 'r"""', "R'''", 'R"""',

          "u'''", 'u"""', "U'''", 'U"""',

          "ur'''", 'ur"""', "Ur'''", 'Ur"""',

          "uR'''", 'uR"""', "UR'''", 'UR"""'):

    triple_quoted[t] = t

single_quoted = {}

for t in ("'", '"',

          "r'", 'r"', "R'", 'R"',

          "u'", 'u"', "U'", 'U"',

          "ur'", 'ur"', "Ur'", 'Ur"',

          "uR'", 'uR"', "UR'", 'UR"' ):

    single_quoted[t] = t

tabsize = 8

class TokenError(Exception): pass

class StopTokenizing(Exception): pass

def printtoken(type, token, (srow, scol), (erow, ecol), line): # for testing

    print "%d,%d-%d,%d:\t%s\t%s" % \

        (srow, scol, erow, ecol, tok_name[type], repr(token))

def tokenize(readline, tokeneater=printtoken):

    """

    The tokenize() function accepts two parameters: one representing the

    input stream, and one providing an output mechanism for tokenize().

    The first parameter, readline, must be a callable object which provides

    the same interface as the readline() method of built-in file objects.

    Each call to the function should return one line of input as a string.

    The second parameter, tokeneater, must also be a callable object. It is

    called once for each token, with five arguments, corresponding to the

    tuples generated by generate_tokens().

    """

    try:

        tokenize_loop(readline, tokeneater)

    except StopTokenizing:

        pass

# backwards compatible interface

def tokenize_loop(readline, tokeneater):

    for token_info in generate_tokens(readline):

        tokeneater(*token_info)

def untokenize(iterable):

    """Transform tokens back into Python source code.

    Each element returned by the iterable must be a token sequence

    with at least two elements, a token number and token value.

    Round-trip invariant:

        # Output text will tokenize the back to the input

        t1 = [tok[:2] for tok in generate_tokens(f.readline)]

        newcode = untokenize(t1)

        readline = iter(newcode.splitlines(1)).next

        t2 = [tok[:2] for tokin generate_tokens(readline)]

        assert t1 == t2

    """

    startline = False

    indents = []

    toks = []

    toks_append = toks.append

    for tok in iterable:

        toknum, tokval = tok[:2]

        if toknum in (NAME, NUMBER):

            tokval += ' '

        if toknum == INDENT:

            indents.append(tokval)

            continue

        elif toknum == DEDENT:

            indents.pop()

            continue

        elif toknum in (NEWLINE, COMMENT, NL):

            startline = True

        elif startline and indents:

            toks_append(indents[-1])

            startline = False

        toks_append(tokval)

    return ''.join(toks)

def generate_tokens(readline):

    """

    The generate_tokens() generator requires one argment, readline, which

    must be a callable object which provides the same interface as the

    readline() method of built-in file objects. Each call to the function

    should return one line of input as a string.  Alternately, readline

    can be a callable function terminating with StopIteration:

        readline = open(myfile).next    # Example of alternate readline

    The generator produces 5-tuples with these members: the token type; the

    token string; a 2-tuple (srow, scol) of ints specifying the row and

    column where the token begins in the source; a 2-tuple (erow, ecol) of

    ints specifying the row and column where the token ends in the source;

    and the line on which the token was found. The line passed is the

    logical line; continuation lines are included.

    """

    lnum = parenlev = continued = 0

    namechars, numchars = string.ascii_letters + '_', '0123456789'

    contstr, needcont = '', 0

    contline = None

    indents = [0]

    while 1:                                   # loop over lines in stream

        try:

            line = readline()

        except StopIteration:

            line = ''

        lnum = lnum + 1

        pos, max = 0, len(line)

        if contstr:                            # continued string

            if not line:

                raise TokenError, ("EOF in multi-line string", strstart)

            endmatch = endprog.match(line)

            if endmatch:

                pos = end = endmatch.end(0)

                yield (STRING, contstr + line[:end],

                           strstart, (lnum, end), contline + line)

                contstr, needcont = '', 0

                contline = None

            elif needcont and line[-2:] != '\\\n' and line[-3:] != '\\\r\n':

                yield (ERRORTOKEN, contstr + line,

                           strstart, (lnum, len(line)), contline)

                contstr = ''

                contline = None

                continue

            else:

                contstr = contstr + line

                contline = contline + line

                continue

        elif parenlev == 0 and not continued:  # new statement

            if not line: break

            column = 0

            while pos < max:                   # measure leading whitespace

                if line[pos] == ' ': column = column + 1

                elif line[pos] == '\t': column = (column/tabsize + 1)*tabsize

                elif line[pos] == '\f': column = 0

                else: break

                pos = pos + 1

            if pos == max: break

            if line[pos] in '#\r\n':           # skip comments or blank lines

                yield ((NL, COMMENT)[line[pos] == '#'], line[pos:],

                           (lnum, pos), (lnum, len(line)), line)

                continue

            if column > indents[-1]:           # count indents or dedents

                indents.append(column)

                yield (INDENT, line[:pos], (lnum, 0), (lnum, pos), line)

            while column < indents[-1]:

                if column not in indents:

                    raise IndentationError(

                        "unindent does not match any outer indentation level",

                        ("<tokenize>", lnum, pos, line))

                indents = indents[:-1]

                yield (DEDENT, '', (lnum, pos), (lnum, pos), line)

        else:                                  # continued statement

            if not line:

                raise TokenError, ("EOF in multi-line statement", (lnum, 0))

            continued = 0

        while pos < max:

            pseudomatch = pseudoprog.match(line, pos)

            if pseudomatch:                                # scan for tokens

                start, end = pseudomatch.span(1)

                spos, epos, pos = (lnum, start), (lnum, end), end

                token, initial = line[start:end], line[start]

                if initial in numchars or \

                   (initial == '.' and token != '.'):      # ordinary number

                    yield (NUMBER, token, spos, epos, line)

                elif initial in '\r\n':

                    yield (parenlev > 0 and NL or NEWLINE,

                               token, spos, epos, line)

                elif initial == '#':

                    yield (COMMENT, token, spos, epos, line)

                elif token in triple_quoted:

                    endprog = endprogs[token]

                    endmatch = endprog.match(line, pos)

                    if endmatch:                           # all on one line

                        pos = endmatch.end(0)

                        token = line[start:pos]

                        yield (STRING, token, spos, (lnum, pos), line)

                    else:

                        strstart = (lnum, start)           # multiple lines

                        contstr = line[start:]

                        contline = line

                        break

                elif initial in single_quoted or \

                    token[:2] in single_quoted or \

                    token[:3] in single_quoted:

                    if token[-1] == '\n':                  # continued string

                        strstart = (lnum, start)

                        endprog = (endprogs[initial] or endprogs[token[1]] or

                                   endprogs[token[2]])

                        contstr, needcont = line[start:], 1

                        contline = line

                        break

                    else:                                  # ordinary string

                        yield (STRING, token, spos, epos, line)

                elif initial in namechars:                 # ordinary name

                    yield (NAME, token, spos, epos, line)

                elif initial == '\\':                      # continued stmt

                    continued = 1

                else:

                    if initial in '([{': parenlev = parenlev + 1

                    elif initial in ')]}': parenlev = parenlev - 1

                    yield (OP, token, spos, epos, line)

            else:

                yield (ERRORTOKEN, line[pos],

                           (lnum, pos), (lnum, pos+1), line)

                pos = pos + 1

    for indent in indents[1:]:                 # pop remaining indent levels

        yield (DEDENT, '', (lnum, 0), (lnum, 0), '')

    yield (ENDMARKER, '', (lnum, 0), (lnum, 0), '')

if __name__ == '__main__':                     # testing

    import sys

    if len(sys.argv) > 1: tokenize(open(sys.argv[1]).readline)

    else: tokenize(sys.stdin.readline)