Package translate :: Package misc :: Module sparse

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# Source Code for Module translate.misc.sparse

      1  #!/usr/bin/env python
      2  # -*- coding: utf-8 -*-
      3
      4  """simple parser / string tokenizer
      5  rather than returning a list of token types etc, we simple return a list of tokens...
      6  each tokenizing function takes a string as input and returns a list of tokens
      7  """
      8
      9  # Copyright 2002, 2003 St James Software
     10  #
     11  # This file is part of translate.
     12  #
     13  # translate is free software; you can redistribute it and/or modify
     14  # it under the terms of the GNU General Public License as published by
     15  # the Free Software Foundation; either version 2 of the License, or
     16  # (at your option) any later version.
     17  #
     18  # translate is distributed in the hope that it will be useful,
     19  # but WITHOUT ANY WARRANTY; without even the implied warranty of
     20  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     21  # GNU General Public License for more details.
     22  #
     23  # You should have received a copy of the GNU General Public License
     24  # along with translate; if not, write to the Free Software
     25  # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
     26
     27 -def stringeval(text):
     28    """takes away repeated quotes (escapes) and returns the string represented by the text"""
     29    stringchar = text[0]
     30    if text[-1] != stringchar or stringchar not in ("'",'"'):
     31      # scratch your head
     32      raise ValueError, "error parsing escaped string: %r" % text
     33    return text[1:-1].replace(stringchar+stringchar,stringchar)
     34
     35 -def stringquote(text):
     36    """escapes quotes as neccessary and returns a string representing the text"""
     37    if "'" in text:
     38      if '"' in text:
     39        return '"' + text.replace('"', '""') + '"'
     40      else:
     41        return '"' + text + '"'
     42    else:
     43      return "'" + text + "'"
     44
     45 -class ParserError(ValueError):
     46    """Intelligent parser error"""
     47 -  def __init__(self, parser, message, tokennum):
     48      """takes a message and the number of the token that caused the error"""
     49      tokenpos = parser.findtokenpos(tokennum)
     50      line, charpos = parser.getlinepos(tokenpos)
     51      ValueError.__init__(self, "%s at line %d, char %d (token %r)" % \
     52          (message, line, charpos, parser.tokens[tokennum]))
     53      self.parser = parser
     54      self.tokennum = tokennum
     55
     56 -class SimpleParser:
     57    """this is a simple parser"""
     58 -  def __init__(self, defaulttokenlist=None, whitespacechars=" \t\r\n", includewhitespacetokens=0):
     59      if defaulttokenlist is None:
     60        self.defaulttokenlist = ['<=', '>=', '==', '!=', '+=', '-=', '*=', '/=', '<>']
     61        self.defaulttokenlist.extend('(),[]:=+-')
     62      else:
     63        self.defaulttokenlist = defaulttokenlist
     64      self.whitespacechars = whitespacechars
     65      self.includewhitespacetokens = includewhitespacetokens
     66      self.standardtokenizers = [self.stringtokenize, self.removewhitespace, self.separatetokens]
     67      self.quotechars = ('"', "'")
     68      self.endquotechars = {'"':'"',"'":"'"}
     69      self.stringescaping = 1
     70
     71 -  def stringtokenize(self, text):
     72      """makes strings in text into tokens..."""
     73      tokens = []
     74      laststart = 0
     75      instring = 0
     76      endstringchar, escapechar = '', '\\'
     77      gotclose, gotescape = 0, 0
     78      for pos in range(len(text)):
     79        char = text[pos]
     80        if instring:
     81          if self.stringescaping and (gotescape or char == escapechar) and not gotclose:
     82            gotescape = not gotescape
     83          elif char == endstringchar:
     84            gotclose = not gotclose
     85          elif gotclose:
     86            tokens.append(text[laststart:pos])
     87            instring, laststart, endstringchar = 0, pos, ''
     88        if not instring:
     89          if char in self.quotechars:
     90            if pos > laststart: tokens.append(text[laststart:pos])
     91            instring, laststart, endstringchar, gotclose = 1, pos, self.endquotechars[char], 0
     92      if laststart < len(text): tokens.append(text[laststart:])
     93      return tokens
     94
     95 -  def keeptogether(self, text):
     96      """checks whether a token should be kept together"""
     97      return self.isstringtoken(text)
     98
     99 -  def isstringtoken(self, text):
    100      """checks whether a token is a string token"""
    101      return text[:1] in self.quotechars
    102
    103 -  def separatetokens(self, text, tokenlist = None):
    104      """this separates out tokens in tokenlist from whitespace etc"""
    105      if self.keeptogether(text): return [text]
    106      if tokenlist is None:
    107        tokenlist = self.defaulttokenlist
    108      # loop through and put tokens into a list
    109      tokens = []
    110      pos = 0
    111      laststart = 0
    112      lentext = len(text)
    113      while pos < lentext:
    114        foundtoken = 0
    115        for token in tokenlist:
    116          lentoken = len(token)
    117          if text[pos:pos+lentoken] == token:
    118            if laststart < pos: tokens.append(text[laststart:pos])
    119            tokens.append(token)
    120            pos += lentoken
    121            foundtoken, laststart = 1, pos
    122            break
    123        if not foundtoken: pos += 1
    124      if laststart < lentext: tokens.append(text[laststart:])
    125      return tokens
    126
    127 -  def removewhitespace(self, text):
    128      """this removes whitespace but lets it separate things out into separate tokens"""
    129      if self.keeptogether(text): return [text]
    130      # loop through and put tokens into a list
    131      tokens = []
    132      pos = 0
    133      inwhitespace = 0
    134      laststart = 0
    135      for pos in range(len(text)):
    136        char = text[pos]
    137        if inwhitespace:
    138          if char not in self.whitespacechars:
    139            if laststart < pos and self.includewhitespacetokens: tokens.append(text[laststart:pos])
    140            inwhitespace, laststart = 0, pos
    141        else:
    142          if char in self.whitespacechars:
    143            if laststart < pos: tokens.append(text[laststart:pos])
    144            inwhitespace, laststart = 1, pos
    145      if laststart < len(text) and (not inwhitespace or self.includewhitespacetokens):
    146        tokens.append(text[laststart:])
    147      return tokens
    148
    149 -  def applytokenizer(self, inputlist, tokenizer):
    150      """apply a tokenizer to a set of text, flattening the result"""
    151      tokenizedlists = [tokenizer(text) for text in inputlist]
    152      joined = []
    153      map(joined.extend, tokenizedlists)
    154      return joined
    155
    156 -  def applytokenizers(self, inputlist, tokenizers):
    157      """apply a set of tokenizers to a set of text, flattening each time"""
    158      for tokenizer in tokenizers:
    159        inputlist = self.applytokenizer(inputlist, tokenizer)
    160      return inputlist
    161
    162 -  def tokenize(self, source, tokenizers=None):
    163      """tokenize the text string with the standard tokenizers"""
    164      self.source = source
    165      if tokenizers is None:
    166        tokenizers = self.standardtokenizers
    167      self.tokens = self.applytokenizers([self.source], tokenizers)
    168      return self.tokens
    169
    170 -  def findtokenpos(self, tokennum):
    171      """finds the position of the given token in the text"""
    172      currenttokenpos = 0
    173      for currenttokennum in range(tokennum+1):
    174        currenttokenpos = self.source.find(self.tokens[currenttokennum], currenttokenpos)
    175      return currenttokenpos
    176
    177 -  def getlinepos(self, tokenpos):
    178      """finds the line and character position of the given character"""
    179      sourcecut = self.source[:tokenpos]
    180      line = sourcecut.count("\n")+1
    181      charpos = tokenpos - sourcecut.rfind("\n")
    182      return line, charpos
    183
    184 -  def raiseerror(self, message, tokennum):
    185      """raises a ParserError"""
    186      raise ParserError(self, message, tokennum)
    187