""" @package antlr3.tree @brief ANTLR3 runtime package, treewizard module A utility module to create ASTs at runtime. See 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 # All rights reserved. # # Redistribution and use in source and binary forms, with or without # modification, are permitted provided that the following conditions # are met: # 1. Redistributions of source code must retain the above copyright # notice, this list of conditions and the following disclaimer. # 2. Redistributions in binary form must reproduce the above copyright # notice, this list of conditions and the following disclaimer in the # documentation and/or other materials provided with the distribution. # 3. The name of the author may not be used to endorse or promote products # derived from this software without specific prior written permission. # # THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR # IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES # OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. # IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, # INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT # NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF # THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. # # end[licence] 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