395 lines
16 KiB
Python
Executable File
395 lines
16 KiB
Python
Executable File
import re
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valid_name_re = re.compile('^[a-zA-Z_][a-zA-Z0-9_]*$')
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reserved_names = ['start', 'middle', 'end', 'null']
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class Token(object):
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def __init__(self, name, rule, y, x, s, **vargs):
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self.name = name
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self.rule = rule
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self.y = y
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self.x = x
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self.string = s
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self.vargs = vargs
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def copy(self):
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return Token(self.name, None, self.y, self.x, self.string, **self.vargs)
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def add_to_string(self, s):
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self.string += s
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def end_x(self):
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return self.x + len(self.string)
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def __eq__(self, other):
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return (self.y == other.y and
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self.x == other.x and
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self.string == other.string and
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self.name == other.name and
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self.vargs == other.vargs)
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def __repr__(self):
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if len(self.string) < 10:
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s = self.string
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else:
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s = self.string[:10] + '...'
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return "<Token(%r, %r, %d, %d, %r)>" % (self.name, self.rule, self.y, self.x, s)
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def render(self):
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return (self,)
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class Rule:
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name = 'abstract'
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def match(self, lexer, context=[], d={}):
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raise Exception, "%s rule cannot match!" % self.name
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def make_token(self, lexer, s, name, **vargs):
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return Token(name, self, lexer.y, lexer.x, s, **vargs)
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class ConstantRule(Rule):
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def __init__(self, name, constant):
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assert valid_name_re.match(name), 'invalid name %r' % name
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assert name not in reserved_names, "reserved rule name: %r" % name
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self.name = name
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self.constant = constant
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def match(self, lexer, context=[], d={}, parent=None):
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if lexer.lines[lexer.y][lexer.x:].startswith(self.constant):
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name = '.'.join(context + [self.name])
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lexer.add_token(self.make_token(lexer, self.constant, name,
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parent=parent))
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lexer.x += len(self.constant)
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return True
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else:
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return False
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class PatternRule(Rule):
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def __init__(self, name, pattern):
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assert valid_name_re.match(name), 'invalid name %r' % name
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assert name not in reserved_names, "reserved rule name: %r" % name
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self.name = name
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self.pattern = pattern
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self.re = re.compile(pattern)
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def match(self, lexer, context=[], d={}, parent=None):
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m = self.re.match(lexer.lines[lexer.y], lexer.x)
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if m:
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name = '.'.join(context + [self.name])
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lexer.add_token(self.make_token(lexer, m.group(0), name,
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parent=parent))
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lexer.x += len(m.group(0))
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return True
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else:
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return False
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class ContextPatternRule(Rule):
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def __init__(self, name, pattern, fallback):
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assert valid_name_re.match(name), 'invalid name %r' % name
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assert name not in reserved_names, "reserved rule name: %r" % name
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self.name = name
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self.pattern = pattern
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self.fallback = fallback
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self.fallback_re = re.compile(fallback)
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def match(self, lexer, context=[], d={}, parent=None):
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try:
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r = re.compile(self.pattern % d)
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except KeyError:
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r = self.fallback_re
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m = r.match(lexer.lines[lexer.y], lexer.x)
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if m:
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name = '.'.join(context + [self.name])
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lexer.add_token(self.make_token(lexer, m.group(0), name,
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parent=parent))
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lexer.x += len(m.group(0))
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return True
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else:
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return False
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class RegionRule(Rule):
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def __init__(self, name, start, grammar, end):
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assert valid_name_re.match(name), 'invalid name %r' % name
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assert name not in reserved_names, "reserved rule name: %r" % name
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self.name = name
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self.start = start
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self.grammar = grammar
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self.end = end
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self.start_re = re.compile(start)
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def _add_from_regex(self, context, name, lexer, m, parent=None):
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t_name = '.'.join(context + [self.name, name])
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t = self.make_token(lexer, m.group(0), t_name, parent=parent)
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lexer.add_token(t)
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lexer.x += len(m.group(0))
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def match(self, lexer, context=[], d={}):
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m = self.start_re.match(lexer.lines[lexer.y], lexer.x)
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# see if we can match out start token
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if m:
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# ok, so create our start token, and get ready to start reading data
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d = m.groupdict()
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self._add_from_regex(context, 'start', lexer, m)
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null_t_name = '.'.join(context + [self.name, 'null'])
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null_t = None
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# if we have an end token, then build it here. notice that it can
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# reference named groups from the start token. if we have no end,
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# well, then, we're never getting out of here alive!
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if self.end:
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end_re = re.compile(self.end % d)
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# ok, so as long as we aren't done (we haven't found an end token),
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# keep reading input
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done = False
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while not done and lexer.y < len(lexer.lines):
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old_y = lexer.y
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# if this line is empty, then we will skip it, but here weinsert
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# an empty null token just so we have something
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if len(lexer.lines[lexer.y]) == 0:
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null_t = Token(null_t_name, None, lexer.y, lexer.x, '')
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lexer.add_token(null_t)
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null_t = None
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# ok, as long as we haven't found the end token, and have more
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# data on the current line to read, we will process tokens
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while not done and lexer.y == old_y and lexer.x < len(lexer.lines[lexer.y]):
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# if we are looking for an end token, then see if we've
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# found it. if so, then we are done!
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if self.end:
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m = end_re.match(lexer.lines[lexer.y], lexer.x)
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if m:
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self._add_from_regex(context, 'end', lexer, m)
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done = True
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break
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# ok, we need to check all our rules now, in order. if we
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# find a token, note that we found one and exit the loop
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found = False
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for rule in self.grammar.rules:
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if rule.match(lexer, context + [self.name], d):
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found = True
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null_t = None
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break
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# if we never found a token, then we need to add another
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# character to the current null token (which we should
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# create if it isn't set).
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if not found:
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if null_t is None:
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null_t = Token(null_t_name, None, lexer.y, lexer.x, '')
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lexer.add_token(null_t)
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null_t.add_to_string(lexer.lines[lexer.y][lexer.x])
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lexer.x += 1
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# ok, since we're soon going to be on a different line (or
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# already are), we want a new null token. so forget about the
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# current one.
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null_t = None
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# if we're still on the same line at this point (and not done)
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# then that means we're finished with the line and should move
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# on to the next one here
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if not done and old_y == lexer.y:
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lexer.y += 1
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lexer.x = 0
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# alright, we're finally done procesing the region, so return true
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return True
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else:
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# region was not matched; we never started. so return false
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return False
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class DualRegionRule(Rule):
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def __init__(self, name, start, grammar1, middle, grammar2, end):
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assert valid_name_re.match(name), 'invalid name %r' % name
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assert name not in reserved_names, "reserved rule name: %r" % name
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self.name = name
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self.start = start
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self.grammar1 = grammar1
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self.middle = middle
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self.grammar2 = grammar2
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self.end = end
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self.start_re = re.compile(start)
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def _add_from_regex(self, context, name, lexer, m, parent=None):
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t_name = '.'.join(context + [self.name, name])
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t = self.make_token(lexer, m.group(0), t_name, parent=parent)
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lexer.add_token(t)
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lexer.x += len(m.group(0))
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def match(self, lexer, context=[], d={}):
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m1 = self.start_re.match(lexer.lines[lexer.y], lexer.x)
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# see if we can match out start token
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if m1:
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# ok, so create our start token, and get ready to start reading data
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self._add_from_regex(context, 'start', lexer, m1)
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null_t_name = '.'.join(context + [self.name, 'null'])
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null_t = None
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d1 = m1.groupdict()
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d2 = {}
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middle_re = re.compile(self.middle % d1)
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# ok, so as long as we aren't done (we haven't found an end token),
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# keep reading input
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done = False
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while not done and lexer.y < len(lexer.lines):
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old_y = lexer.y
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# if this line is empty, then we will skip it, but here weinsert
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# an empty null token just so we have something
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if len(lexer.lines[lexer.y]) == 0:
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null_t = Token(null_t_name, None, lexer.y, lexer.x, '')
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lexer.add_token(null_t)
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null_t = None
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# ok, as long as we haven't found the end token, and have more
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# data on the current line to read, we will process tokens
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while not done and lexer.y == old_y and lexer.x < len(lexer.lines[lexer.y]):
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# see if we have found the middle token. if so, we can then
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# proceed to "stage 2"
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m2 = middle_re.match(lexer.lines[lexer.y], lexer.x)
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if m2:
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d2 = m2.groupdict()
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self._add_from_regex(context, 'middle', lexer, m2)
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done = True
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break
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# ok, we need to check all our rules now, in order. if we
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# find a token, note that we found one and exit the loop
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found = False
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for rule in self.grammar1.rules:
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if rule.match(lexer, context + [self.name], d1):
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found = True
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null_t = None
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break
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# if we never found a token, then we need to add another
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# character to the current null token (which we should
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# create if it isn't set).
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if not found:
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if null_t is None:
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null_t = Token(null_t_name, None, lexer.y, lexer.x, '')
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lexer.add_token(null_t)
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null_t.add_to_string(lexer.lines[lexer.y][lexer.x])
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lexer.x += 1
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# ok, since we're soon going to be on a different line (or
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# already are), we want a new null token. so forget about the
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# current one.
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null_t = None
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# if we're still on the same line at this point (and not done)
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# then that means we're finished with the line and should move
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# on to the next one here
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if not done and old_y == lexer.y:
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lexer.y += 1
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lexer.x = 0
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# ok stage 2 is like stage 1, only we are looking for end tokens
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# instead of middle tokens
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d3 = dict(d1.items() + d2.items())
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end_re = re.compile(self.end % d3)
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# ok, so as long as we aren't done (we haven't found an end token),
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# keep reading input
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done = False
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while not done and lexer.y < len(lexer.lines):
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old_y = lexer.y
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# if this line is empty, then we will skip it, but here weinsert
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# an empty null token just so we have something
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if len(lexer.lines[lexer.y]) == 0:
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null_t = Token(null_t_name, None, lexer.y, lexer.x, '')
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lexer.add_token(null_t)
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null_t = None
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# ok, as long as we haven't found the end token, and have more
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# data on the current line to read, we will process tokens
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while not done and lexer.y == old_y and lexer.x < len(lexer.lines[lexer.y]):
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# see if we have found the middle token. if so, we can then
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# proceed to "stage 2"
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m3 = end_re.match(lexer.lines[lexer.y], lexer.x)
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if m3:
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self._add_from_regex(context, 'end', lexer, m3)
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done = True
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break
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# ok, we need to check all our rules now, in order. if we
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# find a token, note that we found one and exit the loop
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found = False
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for rule in self.grammar2.rules:
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if rule.match(lexer, context + [self.name], d3):
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found = True
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null_t = None
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break
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# if we never found a token, then we need to add another
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# character to the current null token (which we should
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# create if it isn't set).
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if not found:
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if null_t is None:
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null_t = Token(null_t_name, None, lexer.y, lexer.x, '')
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lexer.add_token(null_t)
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null_t.add_to_string(lexer.lines[lexer.y][lexer.x])
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lexer.x += 1
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# ok, since we're soon going to be on a different line (or
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# already are), we want a new null token. so forget about the
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# current one.
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null_t = None
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# if we're still on the same line at this point (and not done)
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# then that means we're finished with the line and should move
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# on to the next one here
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if not done and old_y == lexer.y:
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lexer.y += 1
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lexer.x = 0
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# alright, we're finally done procesing the dual region; return true
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return True
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else:
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# dual region was not matched; we never started. so return false
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return False
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class Grammar:
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rules = []
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def __init__(self):
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for rule in self.rules:
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if hasattr(rule, 'grammar') and rule.grammar is None:
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rule.grammar = self
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class Lexer:
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def __init__(self, name, grammar):
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self.name = name
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self.grammar = grammar
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self.y = 0
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self.x = 0
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self.lines = None
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self.tokens = []
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def add_token(self, t):
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self.tokens.append(t)
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def lex(self, lines, y=0, x=0):
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self.y = y
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self.x = x
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self.lines = lines
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self.tokens = []
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def __iter__(self):
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if self.lines is None:
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raise Exception, "no lines to lex"
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return self
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def next(self):
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null_t_name = 'null'
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null_t = None
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while self.y < len(self.lines):
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line = self.lines[self.y]
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while self.x < len(line):
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curr_t = None
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for rule in self.grammar.rules:
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if rule.match(self):
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assert self.tokens, "AAAAA %s" % repr(self.tokens)
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return self.tokens.pop(0)
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if null_t is None:
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null_t = Token(null_t_name, None, self.y, self.x, '')
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self.add_token(null_t)
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null_t.add_to_string(line[self.x])
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self.x += 1
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null_t = None
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self.y += 1
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self.x = 0
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if self.tokens:
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return self.tokens.pop(0)
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else:
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raise StopIteration
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