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diff --git a/Parser/spark.py b/Parser/spark.py
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-# Copyright (c) 1998-2002 John Aycock
-#
-# Permission is hereby granted, free of charge, to any person obtaining
-# a copy of this software and associated documentation files (the
-# "Software"), to deal in the Software without restriction, including
-# without limitation the rights to use, copy, modify, merge, publish,
-# distribute, sublicense, and/or sell copies of the Software, and to
-# permit persons to whom the Software is furnished to do so, subject to
-# the following conditions:
-#
-# The above copyright notice and this permission notice shall be
-# included in all copies or substantial portions of the Software.
-#
-# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
-# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
-# IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
-# CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
-# TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
-# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-
-__version__ = 'SPARK-0.7 (pre-alpha-5)'
-
-import re
-
-# Compatibility with older pythons.
-def output(string='', end='\n'):
- sys.stdout.write(string + end)
-
-try:
- sorted
-except NameError:
- def sorted(seq):
- seq2 = seq[:]
- seq2.sort()
- return seq2
-
-def _namelist(instance):
- namelist, namedict, classlist = [], {}, [instance.__class__]
- for c in classlist:
- for b in c.__bases__:
- classlist.append(b)
- for name in c.__dict__.keys():
- if name not in namedict:
- namelist.append(name)
- namedict[name] = 1
- return namelist
-
-class GenericScanner:
- def __init__(self, flags=0):
- pattern = self.reflect()
- self.re = re.compile(pattern, re.VERBOSE|flags)
-
- self.index2func = {}
- for name, number in self.re.groupindex.items():
- self.index2func[number-1] = getattr(self, 't_' + name)
-
- def makeRE(self, name):
- doc = getattr(self, name).__doc__
- rv = '(?P<%s>%s)' % (name[2:], doc)
- return rv
-
- def reflect(self):
- rv = []
- for name in _namelist(self):
- if name[:2] == 't_' and name != 't_default':
- rv.append(self.makeRE(name))
-
- rv.append(self.makeRE('t_default'))
- return '|'.join(rv)
-
- def error(self, s, pos):
- output("Lexical error at position %s" % pos)
- raise SystemExit
-
- def tokenize(self, s):
- pos = 0
- n = len(s)
- while pos < n:
- m = self.re.match(s, pos)
- if m is None:
- self.error(s, pos)
-
- groups = m.groups()
- for i in range(len(groups)):
- if groups[i] and i in self.index2func:
- self.index2func[i](groups[i])
- pos = m.end()
-
- def t_default(self, s):
- r'( . | \n )+'
- output("Specification error: unmatched input")
- raise SystemExit
-
-#
-# Extracted from GenericParser and made global so that [un]picking works.
-#
-class _State:
- def __init__(self, stateno, items):
- self.T, self.complete, self.items = [], [], items
- self.stateno = stateno
-
-class GenericParser:
- #
- # An Earley parser, as per J. Earley, "An Efficient Context-Free
- # Parsing Algorithm", CACM 13(2), pp. 94-102. Also J. C. Earley,
- # "An Efficient Context-Free Parsing Algorithm", Ph.D. thesis,
- # Carnegie-Mellon University, August 1968. New formulation of
- # the parser according to J. Aycock, "Practical Earley Parsing
- # and the SPARK Toolkit", Ph.D. thesis, University of Victoria,
- # 2001, and J. Aycock and R. N. Horspool, "Practical Earley
- # Parsing", unpublished paper, 2001.
- #
-
- def __init__(self, start):
- self.rules = {}
- self.rule2func = {}
- self.rule2name = {}
- self.collectRules()
- self.augment(start)
- self.ruleschanged = 1
-
- _NULLABLE = '\e_'
- _START = 'START'
- _BOF = '|-'
-
- #
- # When pickling, take the time to generate the full state machine;
- # some information is then extraneous, too. Unfortunately we
- # can't save the rule2func map.
- #
- def __getstate__(self):
- if self.ruleschanged:
- #
- # XXX - duplicated from parse()
- #
- self.computeNull()
- self.newrules = {}
- self.new2old = {}
- self.makeNewRules()
- self.ruleschanged = 0
- self.edges, self.cores = {}, {}
- self.states = { 0: self.makeState0() }
- self.makeState(0, self._BOF)
- #
- # XXX - should find a better way to do this..
- #
- changes = 1
- while changes:
- changes = 0
- for k, v in self.edges.items():
- if v is None:
- state, sym = k
- if state in self.states:
- self.goto(state, sym)
- changes = 1
- rv = self.__dict__.copy()
- for s in self.states.values():
- del s.items
- del rv['rule2func']
- del rv['nullable']
- del rv['cores']
- return rv
-
- def __setstate__(self, D):
- self.rules = {}
- self.rule2func = {}
- self.rule2name = {}
- self.collectRules()
- start = D['rules'][self._START][0][1][1] # Blech.
- self.augment(start)
- D['rule2func'] = self.rule2func
- D['makeSet'] = self.makeSet_fast
- self.__dict__ = D
-
- #
- # A hook for GenericASTBuilder and GenericASTMatcher. Mess
- # thee not with this; nor shall thee toucheth the _preprocess
- # argument to addRule.
- #
- def preprocess(self, rule, func): return rule, func
-
- def addRule(self, doc, func, _preprocess=1):
- fn = func
- rules = doc.split()
-
- index = []
- for i in range(len(rules)):
- if rules[i] == '::=':
- index.append(i-1)
- index.append(len(rules))
-
- for i in range(len(index)-1):
- lhs = rules[index[i]]
- rhs = rules[index[i]+2:index[i+1]]
- rule = (lhs, tuple(rhs))
-
- if _preprocess:
- rule, fn = self.preprocess(rule, func)
-
- if lhs in self.rules:
- self.rules[lhs].append(rule)
- else:
- self.rules[lhs] = [ rule ]
- self.rule2func[rule] = fn
- self.rule2name[rule] = func.__name__[2:]
- self.ruleschanged = 1
-
- def collectRules(self):
- for name in _namelist(self):
- if name[:2] == 'p_':
- func = getattr(self, name)
- doc = func.__doc__
- self.addRule(doc, func)
-
- def augment(self, start):
- rule = '%s ::= %s %s' % (self._START, self._BOF, start)
- self.addRule(rule, lambda args: args[1], 0)
-
- def computeNull(self):
- self.nullable = {}
- tbd = []
-
- for rulelist in self.rules.values():
- lhs = rulelist[0][0]
- self.nullable[lhs] = 0
- for rule in rulelist:
- rhs = rule[1]
- if len(rhs) == 0:
- self.nullable[lhs] = 1
- continue
- #
- # We only need to consider rules which
- # consist entirely of nonterminal symbols.
- # This should be a savings on typical
- # grammars.
- #
- for sym in rhs:
- if sym not in self.rules:
- break
- else:
- tbd.append(rule)
- changes = 1
- while changes:
- changes = 0
- for lhs, rhs in tbd:
- if self.nullable[lhs]:
- continue
- for sym in rhs:
- if not self.nullable[sym]:
- break
- else:
- self.nullable[lhs] = 1
- changes = 1
-
- def makeState0(self):
- s0 = _State(0, [])
- for rule in self.newrules[self._START]:
- s0.items.append((rule, 0))
- return s0
-
- def finalState(self, tokens):
- #
- # Yuck.
- #
- if len(self.newrules[self._START]) == 2 and len(tokens) == 0:
- return 1
- start = self.rules[self._START][0][1][1]
- return self.goto(1, start)
-
- def makeNewRules(self):
- worklist = []
- for rulelist in self.rules.values():
- for rule in rulelist:
- worklist.append((rule, 0, 1, rule))
-
- for rule, i, candidate, oldrule in worklist:
- lhs, rhs = rule
- n = len(rhs)
- while i < n:
- sym = rhs[i]
- if sym not in self.rules or \
- not self.nullable[sym]:
- candidate = 0
- i = i + 1
- continue
-
- newrhs = list(rhs)
- newrhs[i] = self._NULLABLE+sym
- newrule = (lhs, tuple(newrhs))
- worklist.append((newrule, i+1,
- candidate, oldrule))
- candidate = 0
- i = i + 1
- else:
- if candidate:
- lhs = self._NULLABLE+lhs
- rule = (lhs, rhs)
- if lhs in self.newrules:
- self.newrules[lhs].append(rule)
- else:
- self.newrules[lhs] = [ rule ]
- self.new2old[rule] = oldrule
-
- def typestring(self, token):
- return None
-
- def error(self, token):
- output("Syntax error at or near `%s' token" % token)
- raise SystemExit
-
- def parse(self, tokens):
- sets = [ [(1,0), (2,0)] ]
- self.links = {}
-
- if self.ruleschanged:
- self.computeNull()
- self.newrules = {}
- self.new2old = {}
- self.makeNewRules()
- self.ruleschanged = 0
- self.edges, self.cores = {}, {}
- self.states = { 0: self.makeState0() }
- self.makeState(0, self._BOF)
-
- for i in range(len(tokens)):
- sets.append([])
-
- if sets[i] == []:
- break
- self.makeSet(tokens[i], sets, i)
- else:
- sets.append([])
- self.makeSet(None, sets, len(tokens))
-
- #_dump(tokens, sets, self.states)
-
- finalitem = (self.finalState(tokens), 0)
- if finalitem not in sets[-2]:
- if len(tokens) > 0:
- self.error(tokens[i-1])
- else:
- self.error(None)
-
- return self.buildTree(self._START, finalitem,
- tokens, len(sets)-2)
-
- def isnullable(self, sym):
- #
- # For symbols in G_e only. If we weren't supporting 1.5,
- # could just use sym.startswith().
- #
- return self._NULLABLE == sym[0:len(self._NULLABLE)]
-
- def skip(self, hs, pos=0):
- n = len(hs[1])
- while pos < n:
- if not self.isnullable(hs[1][pos]):
- break
- pos = pos + 1
- return pos
-
- def makeState(self, state, sym):
- assert sym is not None
- #
- # Compute \epsilon-kernel state's core and see if
- # it exists already.
- #
- kitems = []
- for rule, pos in self.states[state].items:
- lhs, rhs = rule
- if rhs[pos:pos+1] == (sym,):
- kitems.append((rule, self.skip(rule, pos+1)))
- core = kitems
-
- core.sort()
- tcore = tuple(core)
- if tcore in self.cores:
- return self.cores[tcore]
- #
- # Nope, doesn't exist. Compute it and the associated
- # \epsilon-nonkernel state together; we'll need it right away.
- #
- k = self.cores[tcore] = len(self.states)
- K, NK = _State(k, kitems), _State(k+1, [])
- self.states[k] = K
- predicted = {}
-
- edges = self.edges
- rules = self.newrules
- for X in K, NK:
- worklist = X.items
- for item in worklist:
- rule, pos = item
- lhs, rhs = rule
- if pos == len(rhs):
- X.complete.append(rule)
- continue
-
- nextSym = rhs[pos]
- key = (X.stateno, nextSym)
- if nextSym not in rules:
- if key not in edges:
- edges[key] = None
- X.T.append(nextSym)
- else:
- edges[key] = None
- if nextSym not in predicted:
- predicted[nextSym] = 1
- for prule in rules[nextSym]:
- ppos = self.skip(prule)
- new = (prule, ppos)
- NK.items.append(new)
- #
- # Problem: we know K needs generating, but we
- # don't yet know about NK. Can't commit anything
- # regarding NK to self.edges until we're sure. Should
- # we delay committing on both K and NK to avoid this
- # hacky code? This creates other problems..
- #
- if X is K:
- edges = {}
-
- if NK.items == []:
- return k
-
- #
- # Check for \epsilon-nonkernel's core. Unfortunately we
- # need to know the entire set of predicted nonterminals
- # to do this without accidentally duplicating states.
- #
- core = sorted(predicted.keys())
- tcore = tuple(core)
- if tcore in self.cores:
- self.edges[(k, None)] = self.cores[tcore]
- return k
-
- nk = self.cores[tcore] = self.edges[(k, None)] = NK.stateno
- self.edges.update(edges)
- self.states[nk] = NK
- return k
-
- def goto(self, state, sym):
- key = (state, sym)
- if key not in self.edges:
- #
- # No transitions from state on sym.
- #
- return None
-
- rv = self.edges[key]
- if rv is None:
- #
- # Target state isn't generated yet. Remedy this.
- #
- rv = self.makeState(state, sym)
- self.edges[key] = rv
- return rv
-
- def gotoT(self, state, t):
- return [self.goto(state, t)]
-
- def gotoST(self, state, st):
- rv = []
- for t in self.states[state].T:
- if st == t:
- rv.append(self.goto(state, t))
- return rv
-
- def add(self, set, item, i=None, predecessor=None, causal=None):
- if predecessor is None:
- if item not in set:
- set.append(item)
- else:
- key = (item, i)
- if item not in set:
- self.links[key] = []
- set.append(item)
- self.links[key].append((predecessor, causal))
-
- def makeSet(self, token, sets, i):
- cur, next = sets[i], sets[i+1]
-
- ttype = token is not None and self.typestring(token) or None
- if ttype is not None:
- fn, arg = self.gotoT, ttype
- else:
- fn, arg = self.gotoST, token
-
- for item in cur:
- ptr = (item, i)
- state, parent = item
- add = fn(state, arg)
- for k in add:
- if k is not None:
- self.add(next, (k, parent), i+1, ptr)
- nk = self.goto(k, None)
- if nk is not None:
- self.add(next, (nk, i+1))
-
- if parent == i:
- continue
-
- for rule in self.states[state].complete:
- lhs, rhs = rule
- for pitem in sets[parent]:
- pstate, pparent = pitem
- k = self.goto(pstate, lhs)
- if k is not None:
- why = (item, i, rule)
- pptr = (pitem, parent)
- self.add(cur, (k, pparent),
- i, pptr, why)
- nk = self.goto(k, None)
- if nk is not None:
- self.add(cur, (nk, i))
-
- def makeSet_fast(self, token, sets, i):
- #
- # Call *only* when the entire state machine has been built!
- # It relies on self.edges being filled in completely, and
- # then duplicates and inlines code to boost speed at the
- # cost of extreme ugliness.
- #
- cur, next = sets[i], sets[i+1]
- ttype = token is not None and self.typestring(token) or None
-
- for item in cur:
- ptr = (item, i)
- state, parent = item
- if ttype is not None:
- k = self.edges.get((state, ttype), None)
- if k is not None:
- #self.add(next, (k, parent), i+1, ptr)
- #INLINED --v
- new = (k, parent)
- key = (new, i+1)
- if new not in next:
- self.links[key] = []
- next.append(new)
- self.links[key].append((ptr, None))
- #INLINED --^
- #nk = self.goto(k, None)
- nk = self.edges.get((k, None), None)
- if nk is not None:
- #self.add(next, (nk, i+1))
- #INLINED --v
- new = (nk, i+1)
- if new not in next:
- next.append(new)
- #INLINED --^
- else:
- add = self.gotoST(state, token)
- for k in add:
- if k is not None:
- self.add(next, (k, parent), i+1, ptr)
- #nk = self.goto(k, None)
- nk = self.edges.get((k, None), None)
- if nk is not None:
- self.add(next, (nk, i+1))
-
- if parent == i:
- continue
-
- for rule in self.states[state].complete:
- lhs, rhs = rule
- for pitem in sets[parent]:
- pstate, pparent = pitem
- #k = self.goto(pstate, lhs)
- k = self.edges.get((pstate, lhs), None)
- if k is not None:
- why = (item, i, rule)
- pptr = (pitem, parent)
- #self.add(cur, (k, pparent),
- # i, pptr, why)
- #INLINED --v
- new = (k, pparent)
- key = (new, i)
- if new not in cur:
- self.links[key] = []
- cur.append(new)
- self.links[key].append((pptr, why))
- #INLINED --^
- #nk = self.goto(k, None)
- nk = self.edges.get((k, None), None)
- if nk is not None:
- #self.add(cur, (nk, i))
- #INLINED --v
- new = (nk, i)
- if new not in cur:
- cur.append(new)
- #INLINED --^
-
- def predecessor(self, key, causal):
- for p, c in self.links[key]:
- if c == causal:
- return p
- assert 0
-
- def causal(self, key):
- links = self.links[key]
- if len(links) == 1:
- return links[0][1]
- choices = []
- rule2cause = {}
- for p, c in links:
- rule = c[2]
- choices.append(rule)
- rule2cause[rule] = c
- return rule2cause[self.ambiguity(choices)]
-
- def deriveEpsilon(self, nt):
- if len(self.newrules[nt]) > 1:
- rule = self.ambiguity(self.newrules[nt])
- else:
- rule = self.newrules[nt][0]
- #output(rule)
-
- rhs = rule[1]
- attr = [None] * len(rhs)
-
- for i in range(len(rhs)-1, -1, -1):
- attr[i] = self.deriveEpsilon(rhs[i])
- return self.rule2func[self.new2old[rule]](attr)
-
- def buildTree(self, nt, item, tokens, k):
- state, parent = item
-
- choices = []
- for rule in self.states[state].complete:
- if rule[0] == nt:
- choices.append(rule)
- rule = choices[0]
- if len(choices) > 1:
- rule = self.ambiguity(choices)
- #output(rule)
-
- rhs = rule[1]
- attr = [None] * len(rhs)
-
- for i in range(len(rhs)-1, -1, -1):
- sym = rhs[i]
- if sym not in self.newrules:
- if sym != self._BOF:
- attr[i] = tokens[k-1]
- key = (item, k)
- item, k = self.predecessor(key, None)
- #elif self.isnullable(sym):
- elif self._NULLABLE == sym[0:len(self._NULLABLE)]:
- attr[i] = self.deriveEpsilon(sym)
- else:
- key = (item, k)
- why = self.causal(key)
- attr[i] = self.buildTree(sym, why[0],
- tokens, why[1])
- item, k = self.predecessor(key, why)
- return self.rule2func[self.new2old[rule]](attr)
-
- def ambiguity(self, rules):
- #
- # XXX - problem here and in collectRules() if the same rule
- # appears in >1 method. Also undefined results if rules
- # causing the ambiguity appear in the same method.
- #
- sortlist = []
- name2index = {}
- for i in range(len(rules)):
- lhs, rhs = rule = rules[i]
- name = self.rule2name[self.new2old[rule]]
- sortlist.append((len(rhs), name))
- name2index[name] = i
- sortlist.sort()
- list = [b for a, b in sortlist]
- return rules[name2index[self.resolve(list)]]
-
- def resolve(self, list):
- #
- # Resolve ambiguity in favor of the shortest RHS.
- # Since we walk the tree from the top down, this
- # should effectively resolve in favor of a "shift".
- #
- return list[0]
-
-#
-# GenericASTBuilder automagically constructs a concrete/abstract syntax tree
-# for a given input. The extra argument is a class (not an instance!)
-# which supports the "__setslice__" and "__len__" methods.
-#
-# XXX - silently overrides any user code in methods.
-#
-
-class GenericASTBuilder(GenericParser):
- def __init__(self, AST, start):
- GenericParser.__init__(self, start)
- self.AST = AST
-
- def preprocess(self, rule, func):
- rebind = lambda lhs, self=self: \
- lambda args, lhs=lhs, self=self: \
- self.buildASTNode(args, lhs)
- lhs, rhs = rule
- return rule, rebind(lhs)
-
- def buildASTNode(self, args, lhs):
- children = []
- for arg in args:
- if isinstance(arg, self.AST):
- children.append(arg)
- else:
- children.append(self.terminal(arg))
- return self.nonterminal(lhs, children)
-
- def terminal(self, token): return token
-
- def nonterminal(self, type, args):
- rv = self.AST(type)
- rv[:len(args)] = args
- return rv
-
-#
-# GenericASTTraversal is a Visitor pattern according to Design Patterns. For
-# each node it attempts to invoke the method n_<node type>, falling
-# back onto the default() method if the n_* can't be found. The preorder
-# traversal also looks for an exit hook named n_<node type>_exit (no default
-# routine is called if it's not found). To prematurely halt traversal
-# of a subtree, call the prune() method -- this only makes sense for a
-# preorder traversal. Node type is determined via the typestring() method.
-#
-
-class GenericASTTraversalPruningException:
- pass
-
-class GenericASTTraversal:
- def __init__(self, ast):
- self.ast = ast
-
- def typestring(self, node):
- return node.type
-
- def prune(self):
- raise GenericASTTraversalPruningException
-
- def preorder(self, node=None):
- if node is None:
- node = self.ast
-
- try:
- name = 'n_' + self.typestring(node)
- if hasattr(self, name):
- func = getattr(self, name)
- func(node)
- else:
- self.default(node)
- except GenericASTTraversalPruningException:
- return
-
- for kid in node:
- self.preorder(kid)
-
- name = name + '_exit'
- if hasattr(self, name):
- func = getattr(self, name)
- func(node)
-
- def postorder(self, node=None):
- if node is None:
- node = self.ast
-
- for kid in node:
- self.postorder(kid)
-
- name = 'n_' + self.typestring(node)
- if hasattr(self, name):
- func = getattr(self, name)
- func(node)
- else:
- self.default(node)
-
-
- def default(self, node):
- pass
-
-#
-# GenericASTMatcher. AST nodes must have "__getitem__" and "__cmp__"
-# implemented.
-#
-# XXX - makes assumptions about how GenericParser walks the parse tree.
-#
-
-class GenericASTMatcher(GenericParser):
- def __init__(self, start, ast):
- GenericParser.__init__(self, start)
- self.ast = ast
-
- def preprocess(self, rule, func):
- rebind = lambda func, self=self: \
- lambda args, func=func, self=self: \
- self.foundMatch(args, func)
- lhs, rhs = rule
- rhslist = list(rhs)
- rhslist.reverse()
-
- return (lhs, tuple(rhslist)), rebind(func)
-
- def foundMatch(self, args, func):
- func(args[-1])
- return args[-1]
-
- def match_r(self, node):
- self.input.insert(0, node)
- children = 0
-
- for child in node:
- if children == 0:
- self.input.insert(0, '(')
- children = children + 1
- self.match_r(child)
-
- if children > 0:
- self.input.insert(0, ')')
-
- def match(self, ast=None):
- if ast is None:
- ast = self.ast
- self.input = []
-
- self.match_r(ast)
- self.parse(self.input)
-
- def resolve(self, list):
- #
- # Resolve ambiguity in favor of the longest RHS.
- #
- return list[-1]
-
-def _dump(tokens, sets, states):
- for i in range(len(sets)):
- output('set %d' % i)
- for item in sets[i]:
- output('\t', item)
- for (lhs, rhs), pos in states[item[0]].items:
- output('\t\t', lhs, '::=', end='')
- output(' '.join(rhs[:pos]), end='')
- output('.', end='')
- output(' '.join(rhs[pos:]))
- if i < len(tokens):
- output()
- output('token %s' % str(tokens[i]))
- output()
generated by cgit v0.12 at 2024-12-28 04:52:28 (GMT)