added html parser and supporting cast
diff --git a/Lib/sgmllib.py b/Lib/sgmllib.py
new file mode 100644
index 0000000..af75e0d
--- /dev/null
+++ b/Lib/sgmllib.py
@@ -0,0 +1,321 @@
+# A parser for SGML, using the derived class as static DTD.
+
+# XXX This only supports those SGML features used by HTML.
+
+# XXX There should be a way to distinguish between PCDATA (parsed
+# character data -- the normal case), RCDATA (replaceable character
+# data -- only char and entity references and end tags are special)
+# and CDATA (character data -- only end tags are special).
+
+
+import regex
+import string
+
+
+# Regular expressions used for parsing
+
+incomplete = regex.compile( \
+ '<!-?\|</[a-zA-Z][a-zA-Z0-9]*[ \t\n]*\|</?\|' + \
+ '&#[a-zA-Z0-9]*\|&[a-zA-Z][a-zA-Z0-9]*\|&')
+entityref = regex.compile('&[a-zA-Z][a-zA-Z0-9]*[;.]')
+charref = regex.compile('&#[a-zA-Z0-9]+;')
+starttagopen = regex.compile('<[a-zA-Z]')
+endtag = regex.compile('</[a-zA-Z][a-zA-Z0-9]*[ \t\n]*>')
+commentopen = regex.compile('<!--')
+
+
+# SGML parser base class -- find tags and call handler functions.
+# Usage: p = SGMLParser(); p.feed(data); ...; p.close().
+# The dtd is defined by deriving a class which defines methods
+# with special names to handle tags: start_foo and end_foo to handle
+# <foo> and </foo>, respectively, or do_foo to handle <foo> by itself.
+# (Tags are converted to lower case for this purpose.) The data
+# between tags is passed to the parser by calling self.handle_data()
+# with some data as argument (the data may be split up in arbutrary
+# chunks). Entity references are passed by calling
+# self.handle_entityref() with the entity reference as argument.
+
+class SGMLParser:
+
+ # Interface -- initialize and reset this instance
+ def __init__(self):
+ self.reset()
+
+ # Interface -- reset this instance. Loses all unprocessed data
+ def reset(self):
+ self.rawdata = ''
+ self.stack = []
+ self.nomoretags = 0
+ self.literal = 0
+
+ # For derived classes only -- enter literal mode (CDATA) till EOF
+ def setnomoretags(self):
+ self.nomoretags = self.literal = 1
+
+ # For derived classes only -- enter literal mode (CDATA)
+ def setliteral(self, *args):
+ self.literal = 1
+
+ # Interface -- feed some data to the parser. Call this as
+ # often as you want, with as little or as much text as you
+ # want (may include '\n'). (This just saves the text, all the
+ # processing is done by process() or close().)
+ def feed(self, data):
+ self.rawdata = self.rawdata + data
+ self.goahead(0)
+
+ # Interface -- handle the remaining data
+ def close(self):
+ self.goahead(1)
+
+ # Internal -- handle data as far as reasonable. May leave state
+ # and data to be processed by a subsequent call. If 'end' is
+ # true, force handling all data as if followed by EOF marker.
+ def goahead(self, end):
+ rawdata = self.rawdata
+ i = 0
+ n = len(rawdata)
+ while i < n:
+ if self.nomoretags:
+ self.handle_data(rawdata[i:n])
+ i = n
+ break
+ j = incomplete.search(rawdata, i)
+ if j < 0: j = n
+ if i < j: self.handle_data(rawdata[i:j])
+ i = j
+ if i == n: break
+ if rawdata[i] == '<':
+ if starttagopen.match(rawdata, i) >= 0:
+ if self.literal:
+ self.handle_data(rawdata[i])
+ i = i+1
+ continue
+ k = self.parse_starttag(i)
+ if k < 0: break
+ i = i + k
+ continue
+ k = endtag.match(rawdata, i)
+ if k >= 0:
+ j = i+k
+ self.parse_endtag(rawdata[i:j])
+ i = j
+ self.literal = 0
+ continue
+ if commentopen.match(rawdata, i) >= 0:
+ if self.literal:
+ self.handle_data(rawdata[i])
+ i = i+1
+ continue
+ k = self.parse_comment(i)
+ if k < 0: break
+ i = i+k
+ continue
+ elif rawdata[i] == '&':
+ k = charref.match(rawdata, i)
+ if k >= 0:
+ j = i+k
+ self.handle_charref(rawdata[i+2:j-1])
+ i = j
+ continue
+ k = entityref.match(rawdata, i)
+ if k >= 0:
+ j = i+k
+ self.handle_entityref(rawdata[i+1:j-1])
+ i = j
+ continue
+ else:
+ raise RuntimeError, 'neither < nor & ??'
+ # We get here only if incomplete matches but
+ # nothing else
+ k = incomplete.match(rawdata, i)
+ if k < 0: raise RuntimeError, 'no incomplete match ??'
+ j = i+k
+ if j == n: break # Really incomplete
+ self.handle_data(rawdata[i:j])
+ i = j
+ # end while
+ if end and i < n:
+ self.handle_data(rawdata[i:n])
+ i = n
+ self.rawdata = rawdata[i:]
+ # XXX if end: check for empty stack
+
+ # Internal -- parse comment, return length or -1 if not ternimated
+ def parse_comment(self, i):
+ rawdata = self.rawdata
+ if rawdata[i:i+4] <> '<!--':
+ raise RuntimeError, 'unexpected call to handle_comment'
+ try:
+ j = string.index(rawdata, '--', i+4)
+ except string.index_error:
+ return -1
+ self.handle_comment(rawdata[i+4: j])
+ j = j+2
+ n = len(rawdata)
+ while j < n and rawdata[j] in ' \t\n': j = j+1
+ if j == n: return -1 # Wait for final '>'
+ if rawdata[j] == '>':
+ j = j+1
+ else:
+ print '*** comment not terminated with >'
+ print repr(rawdata[j-5:j]), '*!*', repr(rawdata[j:j+5])
+ return j-i
+
+ # Internal -- handle starttag, return length or -1 if not terminated
+ def parse_starttag(self, i):
+ rawdata = self.rawdata
+ try:
+ j = string.index(rawdata, '>', i)
+ except string.index_error:
+ return -1
+ # Now parse the data between i+1 and j into a tag and attrs
+ attrs = []
+ tagfind = regex.compile('[a-zA-Z][a-zA-Z0-9]*')
+ attrfind = regex.compile( \
+ '[ \t\n]+\([a-zA-Z][a-zA-Z0-9]*\)' + \
+ '\([ \t\n]*=[ \t\n]*' + \
+ '\(\'[^\']*\';\|"[^"]*"\|[-a-zA-Z0-9./:+*%?!()_#]+\)\)?')
+ k = tagfind.match(rawdata, i+1)
+ if k < 0:
+ raise RuntimeError, 'unexpected call to parse_starttag'
+ k = i+1+k
+ tag = string.lower(rawdata[i+1:k])
+ while k < j:
+ l = attrfind.match(rawdata, k)
+ if l < 0: break
+ regs = attrfind.regs
+ a1, b1 = regs[1]
+ a2, b2 = regs[2]
+ a3, b3 = regs[3]
+ attrname = rawdata[a1:b1]
+ if '=' in rawdata[k:k+l]:
+ attrvalue = rawdata[a3:b3]
+ if attrvalue[:1] == '\'' == attrvalue[-1:] or \
+ attrvalue[:1] == '"' == attrvalue[-1:]:
+ attrvalue = attrvalue[1:-1]
+ else:
+ attrvalue = ''
+ attrs.append(string.lower(attrname), attrvalue)
+ k = k + l
+ j = j+1
+ try:
+ method = getattr(self, 'start_' + tag)
+ except AttributeError:
+ try:
+ method = getattr(self, 'do_' + tag)
+ except AttributeError:
+ self.unknown_starttag(tag, attrs)
+ return j-i
+ method(attrs)
+ return j-i
+ self.stack.append(tag)
+ method(attrs)
+ return j-i
+
+ # Internal -- parse endtag
+ def parse_endtag(self, data):
+ if data[:2] <> '</' or data[-1:] <> '>':
+ raise RuntimeError, 'unexpected call to parse_endtag'
+ tag = string.lower(string.strip(data[2:-1]))
+ try:
+ method = getattr(self, 'end_' + tag)
+ except AttributeError:
+ self.unknown_endtag(tag)
+ return
+ if self.stack and self.stack[-1] == tag:
+ del self.stack[-1]
+ else:
+ print '*** Unbalanced </' + tag + '>'
+ print '*** Stack:', self.stack
+ found = None
+ for i in range(len(self.stack)):
+ if self.stack[i] == tag: found = i
+ if found <> None:
+ del self.stack[found:]
+ method()
+
+ # Example -- handle character reference, no need to override
+ def handle_charref(self, name):
+ try:
+ n = string.atoi(name)
+ except string.atoi_error:
+ self.unknown_charref(name)
+ return
+ if not 0 <= n <= 255:
+ self.unknown_charref(name)
+ return
+ self.handle_data(chr(n))
+
+ # Definition of entities -- derived classes may override
+ entitydefs = \
+ {'lt': '<', 'gt': '>', 'amp': '&', 'quot': '"', 'apos': '\''}
+
+ # Example -- handle entity reference, no need to override
+ def handle_entityref(self, name):
+ table = self.__class__.entitydefs
+ name = string.lower(name)
+ if table.has_key(name):
+ self.handle_data(table[name])
+ else:
+ self.unknown_entityref(name)
+ return
+
+ # Example -- handle data, should be overridden
+ def handle_data(self, data):
+ pass
+
+ # Example -- handle comment, could be overridden
+ def handle_comment(self, data):
+ pass
+
+ # To be overridden -- handlers for unknown objects
+ def unknown_starttag(self, tag, attrs): pass
+ def unknown_endtag(self, tag): pass
+ def unknown_charref(self, ref): pass
+ def unknown_entityref(self, ref): pass
+
+
+class TestSGML(SGMLParser):
+
+ def handle_data(self, data):
+ r = repr(data)
+ if len(r) > 72:
+ r = r[:35] + '...' + r[-35:]
+ print 'data:', r
+
+ def handle_comment(self, data):
+ r = repr(data)
+ if len(r) > 68:
+ r = r[:32] + '...' + r[-32:]
+ print 'comment:', r
+
+ def unknown_starttag(self, tag, attrs):
+ print 'start tag: <' + tag,
+ for name, value in attrs:
+ print name + '=' + '"' + value + '"',
+ print '>'
+
+ def unknown_endtag(self, tag):
+ print 'end tag: </' + tag + '>'
+
+ def unknown_entityref(self, ref):
+ print '*** unknown entity ref: &' + ref + ';'
+
+ def unknown_charref(self, ref):
+ print '*** unknown char ref: &#' + ref + ';'
+
+
+def test():
+ file = 'test.html'
+ f = open(file, 'r')
+ x = TestSGML()
+ while 1:
+ line = f.readline()
+ if not line:
+ x.close()
+ break
+ x.feed(line)
+
+
+#test()