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comparison TAL/HTMLTALParser.py @ 996:03cc9a57cb4c

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author Richard Jones <richard@users.sourceforge.net>
date Fri, 30 Aug 2002 08:46:22 +0000
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995:b59b60306914 996:03cc9a57cb4c
1 ##############################################################################
2 #
3 # Copyright (c) 2001, 2002 Zope Corporation and Contributors.
4 # All Rights Reserved.
5 #
6 # This software is subject to the provisions of the Zope Public License,
7 # Version 2.0 (ZPL). A copy of the ZPL should accompany this distribution.
8 # THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
9 # WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
10 # WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
11 # FOR A PARTICULAR PURPOSE
12 #
13 ##############################################################################
14 """
15 Parse HTML and compile to TALInterpreter intermediate code.
16 """
17
18 import sys
19 import string
20
21 from TALGenerator import TALGenerator
22 from TALDefs import ZOPE_METAL_NS, ZOPE_TAL_NS, METALError, TALError
23 from HTMLParser import HTMLParser, HTMLParseError
24
25 BOOLEAN_HTML_ATTRS = [
26 # List of Boolean attributes in HTML that may be given in
27 # minimized form (e.g. <img ismap> rather than <img ismap="">)
28 # From http://www.w3.org/TR/xhtml1/#guidelines (C.10)
29 "compact", "nowrap", "ismap", "declare", "noshade", "checked",
30 "disabled", "readonly", "multiple", "selected", "noresize",
31 "defer"
32 ]
33
34 EMPTY_HTML_TAGS = [
35 # List of HTML tags with an empty content model; these are
36 # rendered in minimized form, e.g. <img />.
37 # From http://www.w3.org/TR/xhtml1/#dtds
38 "base", "meta", "link", "hr", "br", "param", "img", "area",
39 "input", "col", "basefont", "isindex", "frame",
40 ]
41
42 PARA_LEVEL_HTML_TAGS = [
43 # List of HTML elements that close open paragraph-level elements
44 # and are themselves paragraph-level.
45 "h1", "h2", "h3", "h4", "h5", "h6", "p",
46 ]
47
48 BLOCK_CLOSING_TAG_MAP = {
49 "tr": ("tr", "td", "th"),
50 "td": ("td", "th"),
51 "th": ("td", "th"),
52 "li": ("li",),
53 "dd": ("dd", "dt"),
54 "dt": ("dd", "dt"),
55 }
56
57 BLOCK_LEVEL_HTML_TAGS = [
58 # List of HTML tags that denote larger sections than paragraphs.
59 "blockquote", "table", "tr", "th", "td", "thead", "tfoot", "tbody",
60 "noframe", "ul", "ol", "li", "dl", "dt", "dd", "div",
61 ]
62
63 TIGHTEN_IMPLICIT_CLOSE_TAGS = (PARA_LEVEL_HTML_TAGS
64 + BLOCK_CLOSING_TAG_MAP.keys())
65
66
67 class NestingError(HTMLParseError):
68 """Exception raised when elements aren't properly nested."""
69
70 def __init__(self, tagstack, endtag, position=(None, None)):
71 self.endtag = endtag
72 if tagstack:
73 if len(tagstack) == 1:
74 msg = ('Open tag <%s> does not match close tag </%s>'
75 % (tagstack[0], endtag))
76 else:
77 msg = ('Open tags <%s> do not match close tag </%s>'
78 % (string.join(tagstack, '>, <'), endtag))
79 else:
80 msg = 'No tags are open to match </%s>' % endtag
81 HTMLParseError.__init__(self, msg, position)
82
83 class EmptyTagError(NestingError):
84 """Exception raised when empty elements have an end tag."""
85
86 def __init__(self, tag, position=(None, None)):
87 self.tag = tag
88 msg = 'Close tag </%s> should be removed' % tag
89 HTMLParseError.__init__(self, msg, position)
90
91 class OpenTagError(NestingError):
92 """Exception raised when a tag is not allowed in another tag."""
93
94 def __init__(self, tagstack, tag, position=(None, None)):
95 self.tag = tag
96 msg = 'Tag <%s> is not allowed in <%s>' % (tag, tagstack[-1])
97 HTMLParseError.__init__(self, msg, position)
98
99 class HTMLTALParser(HTMLParser):
100
101 # External API
102
103 def __init__(self, gen=None):
104 HTMLParser.__init__(self)
105 if gen is None:
106 gen = TALGenerator(xml=0)
107 self.gen = gen
108 self.tagstack = []
109 self.nsstack = []
110 self.nsdict = {'tal': ZOPE_TAL_NS, 'metal': ZOPE_METAL_NS}
111
112 def parseFile(self, file):
113 f = open(file)
114 data = f.read()
115 f.close()
116 self.parseString(data)
117
118 def parseString(self, data):
119 self.feed(data)
120 self.close()
121 while self.tagstack:
122 self.implied_endtag(self.tagstack[-1], 2)
123 assert self.nsstack == [], self.nsstack
124
125 def getCode(self):
126 return self.gen.getCode()
127
128 def getWarnings(self):
129 return ()
130
131 # Overriding HTMLParser methods
132
133 def handle_starttag(self, tag, attrs):
134 self.close_para_tags(tag)
135 self.scan_xmlns(attrs)
136 tag, attrlist, taldict, metaldict = self.process_ns(tag, attrs)
137 self.tagstack.append(tag)
138 self.gen.emitStartElement(tag, attrlist, taldict, metaldict,
139 self.getpos())
140 if tag in EMPTY_HTML_TAGS:
141 self.implied_endtag(tag, -1)
142
143 def handle_startendtag(self, tag, attrs):
144 self.close_para_tags(tag)
145 self.scan_xmlns(attrs)
146 tag, attrlist, taldict, metaldict = self.process_ns(tag, attrs)
147 if taldict.get("content"):
148 self.gen.emitStartElement(tag, attrlist, taldict, metaldict,
149 self.getpos())
150 self.gen.emitEndElement(tag, implied=-1)
151 else:
152 self.gen.emitStartElement(tag, attrlist, taldict, metaldict,
153 self.getpos(), isend=1)
154 self.pop_xmlns()
155
156 def handle_endtag(self, tag):
157 if tag in EMPTY_HTML_TAGS:
158 # </img> etc. in the source is an error
159 raise EmptyTagError(tag, self.getpos())
160 self.close_enclosed_tags(tag)
161 self.gen.emitEndElement(tag)
162 self.pop_xmlns()
163 self.tagstack.pop()
164
165 def close_para_tags(self, tag):
166 if tag in EMPTY_HTML_TAGS:
167 return
168 close_to = -1
169 if BLOCK_CLOSING_TAG_MAP.has_key(tag):
170 blocks_to_close = BLOCK_CLOSING_TAG_MAP[tag]
171 for i in range(len(self.tagstack)):
172 t = self.tagstack[i]
173 if t in blocks_to_close:
174 if close_to == -1:
175 close_to = i
176 elif t in BLOCK_LEVEL_HTML_TAGS:
177 close_to = -1
178 elif tag in PARA_LEVEL_HTML_TAGS + BLOCK_LEVEL_HTML_TAGS:
179 i = len(self.tagstack) - 1
180 while i >= 0:
181 closetag = self.tagstack[i]
182 if closetag in BLOCK_LEVEL_HTML_TAGS:
183 break
184 if closetag in PARA_LEVEL_HTML_TAGS:
185 if closetag != "p":
186 raise OpenTagError(self.tagstack, tag, self.getpos())
187 close_to = i
188 i = i - 1
189 if close_to >= 0:
190 while len(self.tagstack) > close_to:
191 self.implied_endtag(self.tagstack[-1], 1)
192
193 def close_enclosed_tags(self, tag):
194 if tag not in self.tagstack:
195 raise NestingError(self.tagstack, tag, self.getpos())
196 while tag != self.tagstack[-1]:
197 self.implied_endtag(self.tagstack[-1], 1)
198 assert self.tagstack[-1] == tag
199
200 def implied_endtag(self, tag, implied):
201 assert tag == self.tagstack[-1]
202 assert implied in (-1, 1, 2)
203 isend = (implied < 0)
204 if tag in TIGHTEN_IMPLICIT_CLOSE_TAGS:
205 # Pick out trailing whitespace from the program, and
206 # insert the close tag before the whitespace.
207 white = self.gen.unEmitWhitespace()
208 else:
209 white = None
210 self.gen.emitEndElement(tag, isend=isend, implied=implied)
211 if white:
212 self.gen.emitRawText(white)
213 self.tagstack.pop()
214 self.pop_xmlns()
215
216 def handle_charref(self, name):
217 self.gen.emitRawText("&#%s;" % name)
218
219 def handle_entityref(self, name):
220 self.gen.emitRawText("&%s;" % name)
221
222 def handle_data(self, data):
223 self.gen.emitRawText(data)
224
225 def handle_comment(self, data):
226 self.gen.emitRawText("<!--%s-->" % data)
227
228 def handle_decl(self, data):
229 self.gen.emitRawText("<!%s>" % data)
230
231 def handle_pi(self, data):
232 self.gen.emitRawText("<?%s>" % data)
233
234 # Internal thingies
235
236 def scan_xmlns(self, attrs):
237 nsnew = {}
238 for key, value in attrs:
239 if key[:6] == "xmlns:":
240 nsnew[key[6:]] = value
241 if nsnew:
242 self.nsstack.append(self.nsdict)
243 self.nsdict = self.nsdict.copy()
244 self.nsdict.update(nsnew)
245 else:
246 self.nsstack.append(self.nsdict)
247
248 def pop_xmlns(self):
249 self.nsdict = self.nsstack.pop()
250
251 def fixname(self, name):
252 if ':' in name:
253 prefix, suffix = string.split(name, ':', 1)
254 if prefix == 'xmlns':
255 nsuri = self.nsdict.get(suffix)
256 if nsuri in (ZOPE_TAL_NS, ZOPE_METAL_NS):
257 return name, name, prefix
258 else:
259 nsuri = self.nsdict.get(prefix)
260 if nsuri == ZOPE_TAL_NS:
261 return name, suffix, 'tal'
262 elif nsuri == ZOPE_METAL_NS:
263 return name, suffix, 'metal'
264 return name, name, 0
265
266 def process_ns(self, name, attrs):
267 attrlist = []
268 taldict = {}
269 metaldict = {}
270 name, namebase, namens = self.fixname(name)
271 for item in attrs:
272 key, value = item
273 key, keybase, keyns = self.fixname(key)
274 ns = keyns or namens # default to tag namespace
275 if ns and ns != 'unknown':
276 item = (key, value, ns)
277 if ns == 'tal':
278 if taldict.has_key(keybase):
279 raise TALError("duplicate TAL attribute " +
280 `keybase`, self.getpos())
281 taldict[keybase] = value
282 elif ns == 'metal':
283 if metaldict.has_key(keybase):
284 raise METALError("duplicate METAL attribute " +
285 `keybase`, self.getpos())
286 metaldict[keybase] = value
287 attrlist.append(item)
288 if namens in ('metal', 'tal'):
289 taldict['tal tag'] = namens
290 return name, attrlist, taldict, metaldict
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