src.templates.spark.py Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of jython Show documentation
Show all versions of jython Show documentation
Jython is an implementation of the high-level, dynamic, object-oriented
language Python written in 100% Pure Java, and seamlessly integrated with
the Java platform. It thus allows you to run Python on any Java platform.
# Copyright (c) 1998-2000 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-0.6.1'
import re
import sys
import string
def _namelist(instance):
namelist, namedict, classlist = [], {}, [instance.__class__]
for c in classlist:
for b in c.__bases__:
classlist.append(b)
for name in dir(c):
if not namedict.has_key(name):
namelist.append(name)
namedict[name] = 1
return namelist
class GenericScanner:
def __init__(self):
pattern = self.reflect()
self.re = re.compile(pattern, re.VERBOSE)
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 string.join(rv, '|')
def error(self, s, pos):
print "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 self.index2func.has_key(i):
self.index2func[i](groups[i])
pos = m.end()
def t_default(self, s):
r'( . | \n )+'
pass
class GenericParser:
def __init__(self, start):
self.rules = {}
self.rule2func = {}
self.rule2name = {}
self.collectRules()
self.startRule = self.augment(start)
self.ruleschanged = 1
_START = 'START'
_EOF = 'EOF'
#
# A hook for GenericASTBuilder and GenericASTMatcher.
#
def preprocess(self, rule, func): return rule, func
def addRule(self, doc, func):
rules = string.split(doc)
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))
rule, fn = self.preprocess(rule, func)
if self.rules.has_key(lhs):
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):
#
# Tempting though it is, this isn't made into a call
# to self.addRule() because the start rule shouldn't
# be subject to preprocessing.
#
startRule = (self._START, ( start, self._EOF ))
self.rule2func[startRule] = lambda args: args[0]
self.rules[self._START] = [ startRule ]
self.rule2name[startRule] = ''
return startRule
def makeFIRST(self):
union = {}
self.first = {}
for rulelist in self.rules.values():
for lhs, rhs in rulelist:
if not self.first.has_key(lhs):
self.first[lhs] = {}
if len(rhs) == 0:
self.first[lhs][None] = 1
continue
sym = rhs[0]
if not self.rules.has_key(sym):
self.first[lhs][sym] = 1
else:
union[(sym, lhs)] = 1
changes = 1
while changes:
changes = 0
for src, dest in union.keys():
destlen = len(self.first[dest])
self.first[dest].update(self.first[src])
if len(self.first[dest]) != destlen:
changes = 1
#
# 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, p. 27.
#
def typestring(self, token):
return None
def error(self, token):
print "Syntax error at or near `%s' token" % token
raise SystemExit
def parse(self, tokens):
tree = {}
tokens.append(self._EOF)
states = { 0: [ (self.startRule, 0, 0) ] }
if self.ruleschanged:
self.makeFIRST()
for i in xrange(len(tokens)):
states[i+1] = []
if states[i] == []:
break
self.buildState(tokens[i], states, i, tree)
#_dump(tokens, states)
if i < len(tokens)-1 or states[i+1] != [(self.startRule, 2, 0)]:
del tokens[-1]
self.error(tokens[i-1])
rv = self.buildTree(tokens, tree, ((self.startRule, 2, 0), i+1))
del tokens[-1]
return rv
def buildState(self, token, states, i, tree):
needsCompletion = {}
state = states[i]
predicted = {}
for item in state:
rule, pos, parent = item
lhs, rhs = rule
#
# A -> a . (completer)
#
if pos == len(rhs):
if len(rhs) == 0:
needsCompletion[lhs] = (item, i)
for pitem in states[parent]:
if pitem is item:
break
prule, ppos, pparent = pitem
plhs, prhs = prule
if prhs[ppos:ppos+1] == (lhs,):
new = (prule,
ppos+1,
pparent)
if new not in state:
state.append(new)
tree[(new, i)] = [(item, i)]
else:
tree[(new, i)].append((item, i))
continue
nextSym = rhs[pos]
#
# A -> a . B (predictor)
#
if self.rules.has_key(nextSym):
#
# Work on completer step some more; for rules
# with empty RHS, the "parent state" is the
# current state we're adding Earley items to,
# so the Earley items the completer step needs
# may not all be present when it runs.
#
if needsCompletion.has_key(nextSym):
new = (rule, pos+1, parent)
olditem_i = needsCompletion[nextSym]
if new not in state:
state.append(new)
tree[(new, i)] = [olditem_i]
else:
tree[(new, i)].append(olditem_i)
#
# Has this been predicted already?
#
if predicted.has_key(nextSym):
continue
predicted[nextSym] = 1
ttype = token is not self._EOF and \
self.typestring(token) or \
None
if ttype is not None:
#
# Even smarter predictor, when the
# token's type is known. The code is
# grungy, but runs pretty fast. Three
# cases are looked for: rules with
# empty RHS; first symbol on RHS is a
# terminal; first symbol on RHS is a
# nonterminal (and isn't nullable).
#
for prule in self.rules[nextSym]:
new = (prule, 0, i)
prhs = prule[1]
if len(prhs) == 0:
state.append(new)
continue
prhs0 = prhs[0]
if not self.rules.has_key(prhs0):
if prhs0 != ttype:
continue
else:
state.append(new)
continue
first = self.first[prhs0]
if not first.has_key(None) and \
not first.has_key(ttype):
continue
state.append(new)
continue
for prule in self.rules[nextSym]:
#
# Smarter predictor, as per Grune &
# Jacobs' _Parsing Techniques_. Not
# as good as FIRST sets though.
#
prhs = prule[1]
if len(prhs) > 0 and \
not self.rules.has_key(prhs[0]) and \
token != prhs[0]:
continue
state.append((prule, 0, i))
#
# A -> a . c (scanner)
#
elif token == nextSym:
#assert new not in states[i+1]
states[i+1].append((rule, pos+1, parent))
def buildTree(self, tokens, tree, root):
stack = []
self.buildTree_r(stack, tokens, -1, tree, root)
return stack[0]
def buildTree_r(self, stack, tokens, tokpos, tree, root):
(rule, pos, parent), state = root
while pos > 0:
want = ((rule, pos, parent), state)
if not tree.has_key(want):
#
# Since pos > 0, it didn't come from closure,
# and if it isn't in tree[], then there must
# be a terminal symbol to the left of the dot.
# (It must be from a "scanner" step.)
#
pos = pos - 1
state = state - 1
stack.insert(0, tokens[tokpos])
tokpos = tokpos - 1
else:
#
# There's a NT to the left of the dot.
# Follow the tree pointer recursively (>1
# tree pointers from it indicates ambiguity).
# Since the item must have come about from a
# "completer" step, the state where the item
# came from must be the parent state of the
# item the tree pointer points to.
#
children = tree[want]
if len(children) > 1:
child = self.ambiguity(children)
else:
child = children[0]
tokpos = self.buildTree_r(stack,
tokens, tokpos,
tree, child)
pos = pos - 1
(crule, cpos, cparent), cstate = child
state = cparent
lhs, rhs = rule
result = self.rule2func[rule](stack[:len(rhs)])
stack[:len(rhs)] = [result]
return tokpos
def ambiguity(self, children):
#
# XXX - problem here and in collectRules() if the same
# rule appears in >1 method. But in that case the
# user probably gets what they deserve :-) Also
# undefined results if rules causing the ambiguity
# appear in the same method.
#
sortlist = []
name2index = {}
for i in range(len(children)):
((rule, pos, parent), index) = children[i]
lhs, rhs = rule
name = self.rule2name[rule]
sortlist.append((len(rhs), name))
name2index[name] = i
sortlist.sort()
list = map(lambda (a,b): b, sortlist)
return children[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_, falling
# back onto the default() method if the n_* can't be found. The preorder
# traversal also looks for an exit hook named n__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, states):
for i in range(len(states)):
print 'state', i
for (lhs, rhs), pos, parent in states[i]:
print '\t', lhs, '::=',
print string.join(rhs[:pos]),
print '.',
print string.join(rhs[pos:]),
print ',', parent
if i < len(tokens):
print
print 'token', str(tokens[i])
print