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Diffstat (limited to 'Demo/tkinter/www/sgmllib.py')
-rwxr-xr-x | Demo/tkinter/www/sgmllib.py | 321 |
1 files changed, 321 insertions, 0 deletions
diff --git a/Demo/tkinter/www/sgmllib.py b/Demo/tkinter/www/sgmllib.py new file mode 100755 index 0000000..af75e0d --- /dev/null +++ b/Demo/tkinter/www/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() |