Mercurial > genshi > genshi-test
comparison genshi/template/interpolation.py @ 500:0742f421caba experimental-inline
Merged revisions 487-603 via svnmerge from
http://svn.edgewall.org/repos/genshi/trunk
| author | cmlenz |
|---|---|
| date | Fri, 01 Jun 2007 17:21:47 +0000 |
| parents | |
| children | 1837f39efd6f |
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| 499:869b7885a516 | 500:0742f421caba |
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| 1 # -*- coding: utf-8 -*- | |
| 2 # | |
| 3 # Copyright (C) 2007 Edgewall Software | |
| 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 | |
| 20 from tokenize import tokenprog | |
| 21 | |
| 22 from genshi.core import TEXT | |
| 23 from genshi.template.base import TemplateSyntaxError, EXPR | |
| 24 from genshi.template.eval import Expression | |
| 25 | |
| 26 __all__ = ['interpolate'] | |
| 27 __docformat__ = 'restructuredtext en' | |
| 28 | |
| 29 NAMESTART = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_' | |
| 30 NAMECHARS = NAMESTART + '.0123456789' | |
| 31 PREFIX = '$' | |
| 32 | |
| 33 def interpolate(text, basedir=None, filename=None, lineno=-1, offset=0, | |
| 34 lookup='lenient'): | |
| 35 """Parse the given string and extract expressions. | |
| 36 | |
| 37 This function is a generator that yields `TEXT` events for literal strings, | |
| 38 and `EXPR` events for expressions, depending on the results of parsing the | |
| 39 string. | |
| 40 | |
| 41 >>> for kind, data, pos in interpolate("hey ${foo}bar"): | |
| 42 ... print kind, `data` | |
| 43 TEXT u'hey ' | |
| 44 EXPR Expression('foo') | |
| 45 TEXT u'bar' | |
| 46 | |
| 47 :param text: the text to parse | |
| 48 :param basedir: base directory of the file in which the text was found | |
| 49 (optional) | |
| 50 :param filename: basename of the file in which the text was found (optional) | |
| 51 :param lineno: the line number at which the text was found (optional) | |
| 52 :param offset: the column number at which the text starts in the source | |
| 53 (optional) | |
| 54 :param lookup: the variable lookup mechanism; either "lenient" (the | |
| 55 default), "strict", or a custom lookup class | |
| 56 :return: a list of `TEXT` and `EXPR` events | |
| 57 :raise TemplateSyntaxError: when a syntax error in an expression is | |
| 58 encountered | |
| 59 """ | |
| 60 filepath = filename | |
| 61 if filepath and basedir: | |
| 62 filepath = os.path.join(basedir, filepath) | |
| 63 pos = [filepath, lineno, offset] | |
| 64 | |
| 65 textbuf = [] | |
| 66 textpos = None | |
| 67 for is_expr, chunk in chain(lex(text, pos, filepath), [(True, '')]): | |
| 68 if is_expr: | |
| 69 if textbuf: | |
| 70 yield TEXT, u''.join(textbuf), textpos | |
| 71 del textbuf[:] | |
| 72 textpos = None | |
| 73 if chunk: | |
| 74 try: | |
| 75 expr = Expression(chunk.strip(), pos[0], pos[1], | |
| 76 lookup=lookup) | |
| 77 yield EXPR, expr, tuple(pos) | |
| 78 except SyntaxError, err: | |
| 79 raise TemplateSyntaxError(err, filepath, pos[1], | |
| 80 pos[2] + (err.offset or 0)) | |
| 81 else: | |
| 82 textbuf.append(chunk) | |
| 83 if textpos is None: | |
| 84 textpos = tuple(pos) | |
| 85 | |
| 86 if '\n' in chunk: | |
| 87 lines = chunk.splitlines() | |
| 88 pos[1] += len(lines) - 1 | |
| 89 pos[2] += len(lines[-1]) | |
| 90 else: | |
| 91 pos[2] += len(chunk) | |
| 92 | |
| 93 def lex(text, textpos, filepath): | |
| 94 offset = pos = 0 | |
| 95 end = len(text) | |
| 96 escaped = False | |
| 97 | |
| 98 while 1: | |
| 99 if escaped: | |
| 100 offset = text.find(PREFIX, offset + 2) | |
| 101 escaped = False | |
| 102 else: | |
| 103 offset = text.find(PREFIX, pos) | |
| 104 if offset < 0 or offset == end - 1: | |
| 105 break | |
| 106 next = text[offset + 1] | |
| 107 | |
| 108 if next == '{': | |
| 109 if offset > pos: | |
| 110 yield False, text[pos:offset] | |
| 111 pos = offset + 2 | |
| 112 level = 1 | |
| 113 while level: | |
| 114 match = tokenprog.match(text, pos) | |
| 115 if match is None: | |
| 116 raise TemplateSyntaxError('invalid syntax', filepath, | |
| 117 *textpos[1:]) | |
| 118 pos = match.end() | |
| 119 tstart, tend = match.regs[3] | |
| 120 token = text[tstart:tend] | |
| 121 if token == '{': | |
| 122 level += 1 | |
| 123 elif token == '}': | |
| 124 level -= 1 | |
| 125 yield True, text[offset + 2:pos - 1] | |
| 126 | |
| 127 elif next in NAMESTART: | |
| 128 if offset > pos: | |
| 129 yield False, text[pos:offset] | |
| 130 pos = offset | |
| 131 pos += 1 | |
| 132 while pos < end: | |
| 133 char = text[pos] | |
| 134 if char not in NAMECHARS: | |
| 135 break | |
| 136 pos += 1 | |
| 137 yield True, text[offset + 1:pos].strip() | |
| 138 | |
| 139 elif not escaped and next == PREFIX: | |
| 140 escaped = True | |
| 141 pos = offset + 1 | |
| 142 | |
| 143 else: | |
| 144 yield False, text[pos:offset + 1] | |
| 145 pos = offset + 1 | |
| 146 | |
| 147 if pos < end: | |
| 148 yield False, text[pos:] |