mirror of
https://github.com/python/cpython.git
synced 2024-11-24 02:15:30 +08:00
850 lines
26 KiB
Python
850 lines
26 KiB
Python
# 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()
|