Mercurial > genshi > genshi-test
annotate genshi/template/interpolation.py @ 902:09cc3627654c experimental-inline
Sync `experimental/inline` branch with [source:trunk@1126].
| author | cmlenz |
|---|---|
| date | Fri, 23 Apr 2010 21:08:26 +0000 |
| parents | 1837f39efd6f |
| children |
| rev | line source |
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| 500 | 1 # -*- coding: utf-8 -*- |
| 2 # | |
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3 # Copyright (C) 2007-2009 Edgewall Software |
| 500 | 4 # All rights reserved. |
| 5 # | |
| 6 # This software is licensed as described in the file COPYING, which | |
| 7 # you should have received as part of this distribution. The terms | |
| 8 # are also available at http://genshi.edgewall.org/wiki/License. | |
| 9 # | |
| 10 # This software consists of voluntary contributions made by many | |
| 11 # individuals. For the exact contribution history, see the revision | |
| 12 # history and logs, available at http://genshi.edgewall.org/log/. | |
| 13 | |
| 14 """String interpolation routines, i.e. the splitting up a given text into some | |
| 15 parts that are literal strings, and others that are Python expressions. | |
| 16 """ | |
| 17 | |
| 18 from itertools import chain | |
| 19 import os | |
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20 import re |
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21 from tokenize import PseudoToken |
| 500 | 22 |
| 23 from genshi.core import TEXT | |
| 24 from genshi.template.base import TemplateSyntaxError, EXPR | |
| 25 from genshi.template.eval import Expression | |
| 26 | |
| 27 __all__ = ['interpolate'] | |
| 28 __docformat__ = 'restructuredtext en' | |
| 29 | |
| 30 NAMESTART = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_' | |
| 31 NAMECHARS = NAMESTART + '.0123456789' | |
| 32 PREFIX = '$' | |
| 33 | |
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34 token_re = re.compile('%s|%s(?s)' % ( |
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35 r'[uU]?[rR]?("""|\'\'\')((?<!\\)\\\1|.)*?\1', |
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36 PseudoToken |
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37 )) |
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38 |
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39 |
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40 def interpolate(text, filepath=None, lineno=-1, offset=0, lookup='strict'): |
| 500 | 41 """Parse the given string and extract expressions. |
| 42 | |
| 43 This function is a generator that yields `TEXT` events for literal strings, | |
| 44 and `EXPR` events for expressions, depending on the results of parsing the | |
| 45 string. | |
| 46 | |
| 47 >>> for kind, data, pos in interpolate("hey ${foo}bar"): | |
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48 ... print('%s %r' % (kind, data)) |
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49 TEXT 'hey ' |
| 500 | 50 EXPR Expression('foo') |
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51 TEXT 'bar' |
| 500 | 52 |
| 53 :param text: the text to parse | |
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54 :param filepath: absolute path to the file in which the text was found |
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55 (optional) |
| 500 | 56 :param lineno: the line number at which the text was found (optional) |
| 57 :param offset: the column number at which the text starts in the source | |
| 58 (optional) | |
| 59 :param lookup: the variable lookup mechanism; either "lenient" (the | |
| 60 default), "strict", or a custom lookup class | |
| 61 :return: a list of `TEXT` and `EXPR` events | |
| 62 :raise TemplateSyntaxError: when a syntax error in an expression is | |
| 63 encountered | |
| 64 """ | |
| 65 pos = [filepath, lineno, offset] | |
| 66 | |
| 67 textbuf = [] | |
| 68 textpos = None | |
| 69 for is_expr, chunk in chain(lex(text, pos, filepath), [(True, '')]): | |
| 70 if is_expr: | |
| 71 if textbuf: | |
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72 yield TEXT, ''.join(textbuf), textpos |
| 500 | 73 del textbuf[:] |
| 74 textpos = None | |
| 75 if chunk: | |
| 76 try: | |
| 77 expr = Expression(chunk.strip(), pos[0], pos[1], | |
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78 lookup=lookup) |
| 500 | 79 yield EXPR, expr, tuple(pos) |
| 80 except SyntaxError, err: | |
| 81 raise TemplateSyntaxError(err, filepath, pos[1], | |
| 82 pos[2] + (err.offset or 0)) | |
| 83 else: | |
| 84 textbuf.append(chunk) | |
| 85 if textpos is None: | |
| 86 textpos = tuple(pos) | |
| 87 | |
| 88 if '\n' in chunk: | |
| 89 lines = chunk.splitlines() | |
| 90 pos[1] += len(lines) - 1 | |
| 91 pos[2] += len(lines[-1]) | |
| 92 else: | |
| 93 pos[2] += len(chunk) | |
| 94 | |
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95 |
| 500 | 96 def lex(text, textpos, filepath): |
| 97 offset = pos = 0 | |
| 98 end = len(text) | |
| 99 escaped = False | |
| 100 | |
| 101 while 1: | |
| 102 if escaped: | |
| 103 offset = text.find(PREFIX, offset + 2) | |
| 104 escaped = False | |
| 105 else: | |
| 106 offset = text.find(PREFIX, pos) | |
| 107 if offset < 0 or offset == end - 1: | |
| 108 break | |
| 109 next = text[offset + 1] | |
| 110 | |
| 111 if next == '{': | |
| 112 if offset > pos: | |
| 113 yield False, text[pos:offset] | |
| 114 pos = offset + 2 | |
| 115 level = 1 | |
| 116 while level: | |
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117 match = token_re.match(text, pos) |
| 500 | 118 if match is None: |
| 119 raise TemplateSyntaxError('invalid syntax', filepath, | |
| 120 *textpos[1:]) | |
| 121 pos = match.end() | |
| 122 tstart, tend = match.regs[3] | |
| 123 token = text[tstart:tend] | |
| 124 if token == '{': | |
| 125 level += 1 | |
| 126 elif token == '}': | |
| 127 level -= 1 | |
| 128 yield True, text[offset + 2:pos - 1] | |
| 129 | |
| 130 elif next in NAMESTART: | |
| 131 if offset > pos: | |
| 132 yield False, text[pos:offset] | |
| 133 pos = offset | |
| 134 pos += 1 | |
| 135 while pos < end: | |
| 136 char = text[pos] | |
| 137 if char not in NAMECHARS: | |
| 138 break | |
| 139 pos += 1 | |
| 140 yield True, text[offset + 1:pos].strip() | |
| 141 | |
| 142 elif not escaped and next == PREFIX: | |
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143 if offset > pos: |
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144 yield False, text[pos:offset] |
| 500 | 145 escaped = True |
| 146 pos = offset + 1 | |
| 147 | |
| 148 else: | |
| 149 yield False, text[pos:offset + 1] | |
| 150 pos = offset + 1 | |
| 151 | |
| 152 if pos < end: | |
| 153 yield False, text[pos:] |