""" @package antlr3.tree
@brief ANTLR3 runtime package, treewizard module
A utility module to create ASTs at runtime.
See <http://www.antlr.org/wiki/display/~admin/2007/07/02/Exploring+Concept+of+TreeWizard> for an overview. Note that the API of the Python implementation is slightly different.
"""
# begin[licence]
#
# [The "BSD licence"]
# Copyright (c) 2005-2012 Terence Parr
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from .constants import INVALID_TOKEN_TYPE
from .tokens import CommonToken
from .tree import CommonTree, CommonTreeAdaptor
def computeTokenTypes(tokenNames):
"""
Compute a dict that is an inverted index of
tokenNames (which maps int token types to names).
"""
if tokenNames:
return dict((name, type) for type, name in enumerate(tokenNames))
return {}
## token types for pattern parser
EOF = -1
BEGIN = 1
END = 2
ID = 3
ARG = 4
PERCENT = 5
COLON = 6
DOT = 7
class TreePatternLexer(object):
def __init__(self, pattern):
## The tree pattern to lex like "(A B C)"
self.pattern = pattern
## Index into input string
self.p = -1
## Current char
self.c = None
## How long is the pattern in char?
self.n = len(pattern)
## Set when token type is ID or ARG
self.sval = None
self.error = False
self.consume()
__idStartChar = frozenset(
'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_'
)
__idChar = __idStartChar | frozenset('0123456789')
def nextToken(self):
self.sval = ""
while self.c != EOF:
if self.c in (' ', '\n', '\r', '\t'):
self.consume()
continue
if self.c in self.__idStartChar:
self.sval += self.c
self.consume()
while self.c in self.__idChar:
self.sval += self.c
self.consume()
return ID
if self.c == '(':
self.consume()
return BEGIN
if self.c == ')':
self.consume()
return END
if self.c == '%':
self.consume()
return PERCENT
if self.c == ':':
self.consume()
return COLON
if self.c == '.':
self.consume()
return DOT
if self.c == '[': # grab [x] as a string, returning x
self.consume()
while self.c != ']':
if self.c == '\\':
self.consume()
if self.c != ']':
self.sval += '\\'
self.sval += self.c
else:
self.sval += self.c
self.consume()
self.consume()
return ARG
self.consume()
self.error = True
return EOF
return EOF
def consume(self):
self.p += 1
if self.p >= self.n:
self.c = EOF
else:
self.c = self.pattern[self.p]
class TreePatternParser(object):
def __init__(self, tokenizer, wizard, adaptor):
self.tokenizer = tokenizer
self.wizard = wizard
self.adaptor = adaptor
self.ttype = tokenizer.nextToken() # kickstart
def pattern(self):
if self.ttype == BEGIN:
return self.parseTree()
elif self.ttype == ID:
node = self.parseNode()
if self.ttype == EOF:
return node
return None # extra junk on end
return None
def parseTree(self):
if self.ttype != BEGIN:
return None
self.ttype = self.tokenizer.nextToken()
root = self.parseNode()
if root is None:
return None
while self.ttype in (BEGIN, ID, PERCENT, DOT):
if self.ttype == BEGIN:
subtree = self.parseTree()
self.adaptor.addChild(root, subtree)
else:
child = self.parseNode()
if child is None:
return None
self.adaptor.addChild(root, child)
if self.ttype != END:
return None
self.ttype = self.tokenizer.nextToken()
return root
def parseNode(self):
# "%label:" prefix
label = None
if self.ttype == PERCENT:
self.ttype = self.tokenizer.nextToken()
if self.ttype != ID:
return None
label = self.tokenizer.sval
self.ttype = self.tokenizer.nextToken()
if self.ttype != COLON:
return None
self.ttype = self.tokenizer.nextToken() # move to ID following colon
# Wildcard?
if self.ttype == DOT:
self.ttype = self.tokenizer.nextToken()
wildcardPayload = CommonToken(0, ".")
node = WildcardTreePattern(wildcardPayload)
if label is not None:
node.label = label
return node
# "ID" or "ID[arg]"
if self.ttype != ID:
return None
tokenName = self.tokenizer.sval
self.ttype = self.tokenizer.nextToken()
if tokenName == "nil":
return self.adaptor.nil()
text = tokenName
# check for arg
arg = None
if self.ttype == ARG:
arg = self.tokenizer.sval
text = arg
self.ttype = self.tokenizer.nextToken()
# create node
treeNodeType = self.wizard.getTokenType(tokenName)
if treeNodeType == INVALID_TOKEN_TYPE:
return None
node = self.adaptor.createFromType(treeNodeType, text)
if label is not None and isinstance(node, TreePattern):
node.label = label
if arg is not None and isinstance(node, TreePattern):
node.hasTextArg = True
return node
class TreePattern(CommonTree):
"""
When using %label:TOKENNAME in a tree for parse(), we must
track the label.
"""
def __init__(self, payload):
super().__init__(payload)
self.label = None
self.hasTextArg = None
def toString(self):
if self.label:
return '%' + self.label + ':' + super().toString()
else:
return super().toString()
class WildcardTreePattern(TreePattern):
pass
class TreePatternTreeAdaptor(CommonTreeAdaptor):
"""This adaptor creates TreePattern objects for use during scan()"""
def createWithPayload(self, payload):
return TreePattern(payload)
class TreeWizard(object):
"""
Build and navigate trees with this object. Must know about the names
of tokens so you have to pass in a map or array of token names (from which
this class can build the map). I.e., Token DECL means nothing unless the
class can translate it to a token type.
In order to create nodes and navigate, this class needs a TreeAdaptor.
This class can build a token type -> node index for repeated use or for
iterating over the various nodes with a particular type.
This class works in conjunction with the TreeAdaptor rather than moving
all this functionality into the adaptor. An adaptor helps build and
navigate trees using methods. This class helps you do it with string
patterns like "(A B C)". You can create a tree from that pattern or
match subtrees against it.
"""
def __init__(self, adaptor=None, tokenNames=None, typeMap=None):
if adaptor is None:
self.adaptor = CommonTreeAdaptor()
else:
self.adaptor = adaptor
if typeMap is None:
self.tokenNameToTypeMap = computeTokenTypes(tokenNames)
else:
if tokenNames:
raise ValueError("Can't have both tokenNames and typeMap")
self.tokenNameToTypeMap = typeMap
def getTokenType(self, tokenName):
"""Using the map of token names to token types, return the type."""
if tokenName in self.tokenNameToTypeMap:
return self.tokenNameToTypeMap[tokenName]
else:
return INVALID_TOKEN_TYPE
def create(self, pattern):
"""
Create a tree or node from the indicated tree pattern that closely
follows ANTLR tree grammar tree element syntax:
(root child1 ... child2).
You can also just pass in a node: ID
Any node can have a text argument: ID[foo]
(notice there are no quotes around foo--it's clear it's a string).
nil is a special name meaning "give me a nil node". Useful for
making lists: (nil A B C) is a list of A B C.
"""
tokenizer = TreePatternLexer(pattern)
parser = TreePatternParser(tokenizer, self, self.adaptor)
return parser.pattern()
def index(self, tree):
"""Walk the entire tree and make a node name to nodes mapping.
For now, use recursion but later nonrecursive version may be
more efficient. Returns a dict int -> list where the list is
of your AST node type. The int is the token type of the node.
"""
m = {}
self._index(tree, m)
return m
def _index(self, t, m):
"""Do the work for index"""
if t is None:
return
ttype = self.adaptor.getType(t)
elements = m.get(ttype)
if elements is None:
m[ttype] = elements = []
elements.append(t)
for i in range(self.adaptor.getChildCount(t)):
child = self.adaptor.getChild(t, i)
self._index(child, m)
def find(self, tree, what):
"""Return a list of matching token.
what may either be an integer specifzing the token type to find or
a string with a pattern that must be matched.
"""
if isinstance(what, int):
return self._findTokenType(tree, what)
elif isinstance(what, str):
return self._findPattern(tree, what)
else:
raise TypeError("'what' must be string or integer")
def _findTokenType(self, t, ttype):
"""Return a List of tree nodes with token type ttype"""
nodes = []
def visitor(tree, parent, childIndex, labels):
nodes.append(tree)
self.visit(t, ttype, visitor)
return nodes
def _findPattern(self, t, pattern):
"""Return a List of subtrees matching pattern."""
subtrees = []
# Create a TreePattern from the pattern
tokenizer = TreePatternLexer(pattern)
parser = TreePatternParser(tokenizer, self, TreePatternTreeAdaptor())
tpattern = parser.pattern()
# don't allow invalid patterns
if (tpattern is None or tpattern.isNil()
or isinstance(tpattern, WildcardTreePattern)):
return None
rootTokenType = tpattern.getType()
def visitor(tree, parent, childIndex, label):
if self._parse(tree, tpattern, None):
subtrees.append(tree)
self.visit(t, rootTokenType, visitor)
return subtrees
def visit(self, tree, what, visitor):
"""Visit every node in tree matching what, invoking the visitor.
If what is a string, it is parsed as a pattern and only matching
subtrees will be visited.
The implementation uses the root node of the pattern in combination
with visit(t, ttype, visitor) so nil-rooted patterns are not allowed.
Patterns with wildcard roots are also not allowed.
If what is an integer, it is used as a token type and visit will match
all nodes of that type (this is faster than the pattern match).
The labels arg of the visitor action method is never set (it's None)
since using a token type rather than a pattern doesn't let us set a
label.
"""
if isinstance(what, int):
self._visitType(tree, None, 0, what, visitor)
elif isinstance(what, str):
self._visitPattern(tree, what, visitor)
else:
raise TypeError("'what' must be string or integer")
def _visitType(self, t, parent, childIndex, ttype, visitor):
"""Do the recursive work for visit"""
if t is None:
return
if self.adaptor.getType(t) == ttype:
visitor(t, parent, childIndex, None)
for i in range(self.adaptor.getChildCount(t)):
child = self.adaptor.getChild(t, i)
self._visitType(child, t, i, ttype, visitor)
def _visitPattern(self, tree, pattern, visitor):
"""
For all subtrees that match the pattern, execute the visit action.
"""
# Create a TreePattern from the pattern
tokenizer = TreePatternLexer(pattern)
parser = TreePatternParser(tokenizer, self, TreePatternTreeAdaptor())
tpattern = parser.pattern()
# don't allow invalid patterns
if (tpattern is None or tpattern.isNil()
or isinstance(tpattern, WildcardTreePattern)):
return
rootTokenType = tpattern.getType()
def rootvisitor(tree, parent, childIndex, labels):
labels = {}
if self._parse(tree, tpattern, labels):
visitor(tree, parent, childIndex, labels)
self.visit(tree, rootTokenType, rootvisitor)
def parse(self, t, pattern, labels=None):
"""
Given a pattern like (ASSIGN %lhs:ID %rhs:.) with optional labels
on the various nodes and '.' (dot) as the node/subtree wildcard,
return true if the pattern matches and fill the labels Map with
the labels pointing at the appropriate nodes. Return false if
the pattern is malformed or the tree does not match.
If a node specifies a text arg in pattern, then that must match
for that node in t.
"""
tokenizer = TreePatternLexer(pattern)
parser = TreePatternParser(tokenizer, self, TreePatternTreeAdaptor())
tpattern = parser.pattern()
return self._parse(t, tpattern, labels)
def _parse(self, t1, tpattern, labels):
"""
Do the work for parse. Check to see if the tpattern fits the
structure and token types in t1. Check text if the pattern has
text arguments on nodes. Fill labels map with pointers to nodes
in tree matched against nodes in pattern with labels.
"""
# make sure both are non-null
if t1 is None or tpattern is None:
return False
# check roots (wildcard matches anything)
if not isinstance(tpattern, WildcardTreePattern):
if self.adaptor.getType(t1) != tpattern.getType():
return False
# if pattern has text, check node text
if (tpattern.hasTextArg
and self.adaptor.getText(t1) != tpattern.getText()):
return False
if tpattern.label is not None and labels is not None:
# map label in pattern to node in t1
labels[tpattern.label] = t1
# check children
n1 = self.adaptor.getChildCount(t1)
n2 = tpattern.getChildCount()
if n1 != n2:
return False
for i in range(n1):
child1 = self.adaptor.getChild(t1, i)
child2 = tpattern.getChild(i)
if not self._parse(child1, child2, labels):
return False
return True
def equals(self, t1, t2, adaptor=None):
"""
Compare t1 and t2; return true if token types/text, structure match
exactly.
The trees are examined in their entirety so that (A B) does not match
(A B C) nor (A (B C)).
"""
if adaptor is None:
adaptor = self.adaptor
return self._equals(t1, t2, adaptor)
def _equals(self, t1, t2, adaptor):
# make sure both are non-null
if t1 is None or t2 is None:
return False
# check roots
if adaptor.getType(t1) != adaptor.getType(t2):
return False
if adaptor.getText(t1) != adaptor.getText(t2):
return False
# check children
n1 = adaptor.getChildCount(t1)
n2 = adaptor.getChildCount(t2)
if n1 != n2:
return False
for i in range(n1):
child1 = adaptor.getChild(t1, i)
child2 = adaptor.getChild(t2, i)
if not self._equals(child1, child2, adaptor):
return False
return True