ParserRuleContext.js

/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
 * Use of this file is governed by the BSD 3-clause license that
 * can be found in the LICENSE.txt file in the project root.
 */

//* A rule invocation record for parsing.
//
//  Contains all of the information about the current rule not stored in the
//  RuleContext. It handles parse tree children list, Any ATN state
//  tracing, and the default values available for rule indications:
//  start, stop, rule index, current alt number, current
//  ATN state.
//
//  Subclasses made for each rule and grammar track the parameters,
//  return values, locals, and labels specific to that rule. These
//  are the objects that are returned from rules.
//
//  Note text is not an actual field of a rule return value; it is computed
//  from start and stop using the input stream's toString() method.  I
//  could add a ctor to this so that we can pass in and store the input
//  stream, but I'm not sure we want to do that.  It would seem to be undefined
//  to get the .text property anyway if the rule matches tokens from multiple
//  input streams.
//
//  I do not use getters for fields of objects that are used simply to
//  group values such as this aggregate.  The getters/setters are there to
//  satisfy the superclass interface.

var RuleContext = require('./RuleContext').RuleContext;
var Tree = require('./tree/Tree');
var INVALID_INTERVAL = Tree.INVALID_INTERVAL;
var TerminalNode = Tree.TerminalNode;
var TerminalNodeImpl = Tree.TerminalNodeImpl;
var ErrorNodeImpl = Tree.ErrorNodeImpl;
var Interval = require("./IntervalSet").Interval;

function ParserRuleContext(parent, invokingStateNumber) {
	parent = parent || null;
	invokingStateNumber = invokingStateNumber || null;
	RuleContext.call(this, parent, invokingStateNumber);
	this.ruleIndex = -1;
    // * If we are debugging or building a parse tree for a visitor,
    // we need to track all of the tokens and rule invocations associated
    // with this rule's context. This is empty for parsing w/o tree constr.
    // operation because we don't the need to track the details about
    // how we parse this rule.
    // /
    this.children = null;
    this.start = null;
    this.stop = null;
    // The exception that forced this rule to return. If the rule successfully
    // completed, this is {@code null}.
    this.exception = null;
}

ParserRuleContext.prototype = Object.create(RuleContext.prototype);
ParserRuleContext.prototype.constructor = ParserRuleContext;

// * COPY a ctx (I'm deliberately not using copy constructor)///
ParserRuleContext.prototype.copyFrom = function(ctx) {
    // from RuleContext
    this.parentCtx = ctx.parentCtx;
    this.invokingState = ctx.invokingState;
    this.children = null;
    this.start = ctx.start;
    this.stop = ctx.stop;
    // copy any error nodes to alt label node
    if(ctx.children) {
        this.children = [];
        // reset parent pointer for any error nodes
    	ctx.children.map(function(child) {
    		if (child instanceof ErrorNodeImpl) {
                this.children.push(child);
                child.parentCtx = this;
            }
		}, this);
	}
};

// Double dispatch methods for listeners
ParserRuleContext.prototype.enterRule = function(listener) {
};

ParserRuleContext.prototype.exitRule = function(listener) {
};

// * Does not set parent link; other add methods do that///
ParserRuleContext.prototype.addChild = function(child) {
    if (this.children === null) {
        this.children = [];
    }
    this.children.push(child);
    return child;
};

// * Used by enterOuterAlt to toss out a RuleContext previously added as
// we entered a rule. If we have // label, we will need to remove
// generic ruleContext object.
// /
ParserRuleContext.prototype.removeLastChild = function() {
    if (this.children !== null) {
        this.children.pop();
    }
};

ParserRuleContext.prototype.addTokenNode = function(token) {
    var node = new TerminalNodeImpl(token);
    this.addChild(node);
    node.parentCtx = this;
    return node;
};

ParserRuleContext.prototype.addErrorNode = function(badToken) {
    var node = new ErrorNodeImpl(badToken);
    this.addChild(node);
    node.parentCtx = this;
    return node;
};

ParserRuleContext.prototype.getChild = function(i, type) {
	type = type || null;
	if (this.children === null || i < 0 || i >= this.children.length) {
		return null;
	}
	if (type === null) {
		return this.children[i];
	} else {
		for(var j=0; j<this.children.length; j++) {
			var child = this.children[j];
			if(child instanceof type) {
				if(i===0) {
					return child;
				} else {
					i -= 1;
				}
			}
		}
		return null;
    }
};


ParserRuleContext.prototype.getToken = function(ttype, i) {
	if (this.children === null || i < 0 || i >= this.children.length) {
		return null;
	}
	for(var j=0; j<this.children.length; j++) {
		var child = this.children[j];
		if (child instanceof TerminalNode) {
			if (child.symbol.type === ttype) {
				if(i===0) {
					return child;
				} else {
					i -= 1;
				}
			}
        }
	}
    return null;
};

ParserRuleContext.prototype.getTokens = function(ttype ) {
    if (this.children=== null) {
        return [];
    } else {
		var tokens = [];
		for(var j=0; j<this.children.length; j++) {
			var child = this.children[j];
			if (child instanceof TerminalNode) {
				if (child.symbol.type === ttype) {
					tokens.push(child);
				}
			}
		}
		return tokens;
    }
};

ParserRuleContext.prototype.getTypedRuleContext = function(ctxType, i) {
    return this.getChild(i, ctxType);
};

ParserRuleContext.prototype.getTypedRuleContexts = function(ctxType) {
    if (this.children=== null) {
        return [];
    } else {
		var contexts = [];
		for(var j=0; j<this.children.length; j++) {
			var child = this.children[j];
			if (child instanceof ctxType) {
				contexts.push(child);
			}
		}
		return contexts;
	}
};

ParserRuleContext.prototype.getChildCount = function() {
	if (this.children=== null) {
		return 0;
	} else {
		return this.children.length;
	}
};

ParserRuleContext.prototype.getSourceInterval = function() {
    if( this.start === null || this.stop === null) {
        return INVALID_INTERVAL;
    } else {
        return new Interval(this.start.tokenIndex, this.stop.tokenIndex);
    }
};

RuleContext.EMPTY = new ParserRuleContext();

function InterpreterRuleContext(parent, invokingStateNumber, ruleIndex) {
	ParserRuleContext.call(parent, invokingStateNumber);
    this.ruleIndex = ruleIndex;
    return this;
}

InterpreterRuleContext.prototype = Object.create(ParserRuleContext.prototype);
InterpreterRuleContext.prototype.constructor = InterpreterRuleContext;

exports.ParserRuleContext = ParserRuleContext;