Python3.src.antlr4.tree.ParseTreeMatch.py Maven / Gradle / Ivy

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A collection of tests for ANTLR 4 Runtime libraries.
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#
# [The "BSD license"]
# Copyright (c) 2013 Terence Parr
# Copyright (c) 2013 Sam Harwell
# Copyright (c) 2014 Eric Vergnaud
# 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.
#


#
# Represents the result of matching a {@link ParseTree} against a tree pattern.
#
from io import StringIO
from antlr4.tree.ParseTreePattern import ParseTreePattern
from antlr4.tree.Tree import ParseTree


class ParseTreeMatch(object):

    #
    # Constructs a new instance of {@link ParseTreeMatch} from the specified
    # parse tree and pattern.
    #
    # @param tree The parse tree to match against the pattern.
    # @param pattern The parse tree pattern.
    # @param labels A mapping from label names to collections of
    # {@link ParseTree} objects located by the tree pattern matching process.
    # @param mismatchedNode The first node which failed to match the tree
    # pattern during the matching process.
    #
    # @exception IllegalArgumentException if {@code tree} is {@code null}
    # @exception IllegalArgumentException if {@code pattern} is {@code null}
    # @exception IllegalArgumentException if {@code labels} is {@code null}
    #
    def __init__(self, tree:ParseTree, pattern:ParseTreePattern, labels:dict, mismatchedNode:ParseTree):
        if tree is None:
            raise Exception("tree cannot be null")
        if pattern is None:
            raise Exception("pattern cannot be null")
        if labels is None:
            raise Exception("labels cannot be null")
        self.tree = tree
        self.pattern = pattern
        self.labels = labels
        self.mismatchedNode = mismatchedNode

    #
    # Get the last node associated with a specific {@code label}.
    #
    # For example, for pattern {@code }, {@code get("id")} returns the
    # node matched for that {@code ID}. If more than one node
    # matched the specified label, only the last is returned. If there is
    # no node associated with the label, this returns {@code null}.
    #
    # Pattern tags like {@code } and {@code } without labels are
    # considered to be labeled with {@code ID} and {@code expr}, respectively.
    #
    # @param label The label to check.
    #
    # @return The last {@link ParseTree} to match a tag with the specified
    # label, or {@code null} if no parse tree matched a tag with the label.
    #
    def get(self, label:str):
        parseTrees = self.labels.get(label, None)
        if parseTrees is None or len(parseTrees)==0:
            return None
        else:
            return parseTrees[len(parseTrees)-1]

    #
    # Return all nodes matching a rule or token tag with the specified label.
    #
    # If the {@code label} is the name of a parser rule or token in the
    # grammar, the resulting list will contain both the parse trees matching
    # rule or tags explicitly labeled with the label and the complete set of
    # parse trees matching the labeled and unlabeled tags in the pattern for
    # the parser rule or token. For example, if {@code label} is {@code "foo"},
    # the result will contain all of the following.
    #
    # 
    # Parse tree nodes matching tags of the form {@code } and
    # {@code }.
    # Parse tree nodes matching tags of the form {@code }.
    # Parse tree nodes matching tags of the form {@code }.
    # 
    #
    # @param label The label.
    #
    # @return A collection of all {@link ParseTree} nodes matching tags with
    # the specified {@code label}. If no nodes matched the label, an empty list
    # is returned.
    #
    def getAll(self, label:str):
        nodes = self.labels.get(label, None)
        if nodes is None:
            return list()
        else:
            return nodes


    #
    # Gets a value indicating whether the match operation succeeded.
    #
    # @return {@code true} if the match operation succeeded; otherwise,
    # {@code false}.
    #
    def succeeded(self):
        return self.mismatchedNode is None

    #
    # {@inheritDoc}
    #
    def __str__(self):
        with StringIO() as buf:
            buf.write("Match ")
            buf.write("succeeded" if self.succeeded() else "failed")
            buf.write("; found ")
            buf.write(str(len(self.labels)))
            buf.write(" labels")
            return buf.getvalue()