refactored ATN to be an es6 class
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Camilo Roca
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225249fdae
commit
e7b935e7e2
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@ -6,91 +6,117 @@
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var LL1Analyzer = require('./../LL1Analyzer').LL1Analyzer;
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var IntervalSet = require('./../IntervalSet').IntervalSet;
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function ATN(grammarType , maxTokenType) {
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class ATN {
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constructor(grammarType , maxTokenType) {
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// Used for runtime deserialization of ATNs from strings///
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// The type of the ATN.
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this.grammarType = grammarType;
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// The maximum value for any symbol recognized by a transition in the ATN.
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this.maxTokenType = maxTokenType;
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this.states = [];
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// Each subrule/rule is a decision point and we must track them so we
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// can go back later and build DFA predictors for them. This includes
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// all the rules, subrules, optional blocks, ()+, ()* etc...
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this.decisionToState = [];
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// Maps from rule index to starting state number.
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this.ruleToStartState = [];
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// Maps from rule index to stop state number.
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this.ruleToStopState = null;
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this.modeNameToStartState = {};
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// For lexer ATNs, this maps the rule index to the resulting token type.
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// For parser ATNs, this maps the rule index to the generated bypass token
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// type if the
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// {@link ATNDeserializationOptions//isGenerateRuleBypassTransitions}
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// deserialization option was specified; otherwise, this is {@code null}.
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this.ruleToTokenType = null;
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// For lexer ATNs, this is an array of {@link LexerAction} objects which may
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// be referenced by action transitions in the ATN.
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this.lexerActions = null;
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this.modeToStartState = [];
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return this;
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}
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// Used for runtime deserialization of ATNs from strings///
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// The type of the ATN.
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this.grammarType = grammarType;
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// The maximum value for any symbol recognized by a transition in the ATN.
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this.maxTokenType = maxTokenType;
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this.states = [];
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// Each subrule/rule is a decision point and we must track them so we
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// can go back later and build DFA predictors for them. This includes
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// all the rules, subrules, optional blocks, ()+, ()* etc...
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this.decisionToState = [];
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// Maps from rule index to starting state number.
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this.ruleToStartState = [];
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// Maps from rule index to stop state number.
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this.ruleToStopState = null;
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this.modeNameToStartState = {};
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// For lexer ATNs, this maps the rule index to the resulting token type.
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// For parser ATNs, this maps the rule index to the generated bypass token
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// type if the
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// {@link ATNDeserializationOptions//isGenerateRuleBypassTransitions}
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// deserialization option was specified; otherwise, this is {@code null}.
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this.ruleToTokenType = null;
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// For lexer ATNs, this is an array of {@link LexerAction} objects which may
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// be referenced by action transitions in the ATN.
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this.lexerActions = null;
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this.modeToStartState = [];
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}
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// Compute the set of valid tokens that can occur starting in state {@code s}.
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// If {@code ctx} is null, the set of tokens will not include what can follow
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// the rule surrounding {@code s}. In other words, the set will be
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// restricted to tokens reachable staying within {@code s}'s rule.
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ATN.prototype.nextTokensInContext = function(s, ctx) {
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var anal = new LL1Analyzer(this);
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return anal.LOOK(s, null, ctx);
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};
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nextTokensInContext(s, ctx) {
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var anal = new LL1Analyzer(this);
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return anal.LOOK(s, null, ctx);
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}
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// Compute the set of valid tokens that can occur starting in {@code s} and
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// staying in same rule. {@link Token//EPSILON} is in set if we reach end of
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// rule.
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ATN.prototype.nextTokensNoContext = function(s) {
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if (s.nextTokenWithinRule !== null ) {
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nextTokensNoContext(s) {
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if (s.nextTokenWithinRule !== null ) {
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return s.nextTokenWithinRule;
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}
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s.nextTokenWithinRule = this.nextTokensInContext(s, null);
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s.nextTokenWithinRule.readOnly = true;
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return s.nextTokenWithinRule;
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}
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s.nextTokenWithinRule = this.nextTokensInContext(s, null);
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s.nextTokenWithinRule.readOnly = true;
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return s.nextTokenWithinRule;
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};
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ATN.prototype.nextTokens = function(s, ctx) {
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if ( ctx===undefined ) {
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return this.nextTokensNoContext(s);
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} else {
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return this.nextTokensInContext(s, ctx);
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nextTokens(s, ctx) {
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if ( ctx===undefined ) {
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return this.nextTokensNoContext(s);
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} else {
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return this.nextTokensInContext(s, ctx);
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}
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}
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};
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ATN.prototype.addState = function( state) {
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if ( state !== null ) {
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state.atn = this;
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state.stateNumber = this.states.length;
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addState(state) {
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if ( state !== null ) {
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state.atn = this;
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state.stateNumber = this.states.length;
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}
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this.states.push(state);
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}
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this.states.push(state);
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};
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ATN.prototype.removeState = function( state) {
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this.states[state.stateNumber] = null; // just free mem, don't shift states in list
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};
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ATN.prototype.defineDecisionState = function( s) {
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this.decisionToState.push(s);
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s.decision = this.decisionToState.length-1;
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return s.decision;
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};
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ATN.prototype.getDecisionState = function( decision) {
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if (this.decisionToState.length===0) {
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return null;
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} else {
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return this.decisionToState[decision];
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removeState(state) {
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this.states[state.stateNumber] = null; // just free mem, don't shift states in list
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}
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};
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defineDecisionState(s) {
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this.decisionToState.push(s);
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s.decision = this.decisionToState.length-1;
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return s.decision;
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}
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getDecisionState(decision) {
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if (this.decisionToState.length===0) {
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return null;
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} else {
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return this.decisionToState[decision];
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}
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}
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getExpectedTokens(stateNumber, ctx ) {
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if ( stateNumber < 0 || stateNumber >= this.states.length ) {
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throw("Invalid state number.");
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}
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var s = this.states[stateNumber];
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var following = this.nextTokens(s);
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if (!following.contains(Token.EPSILON)) {
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return following;
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}
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var expected = new IntervalSet();
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expected.addSet(following);
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expected.removeOne(Token.EPSILON);
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while (ctx !== null && ctx.invokingState >= 0 && following.contains(Token.EPSILON)) {
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var invokingState = this.states[ctx.invokingState];
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var rt = invokingState.transitions[0];
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following = this.nextTokens(rt.followState);
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expected.addSet(following);
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expected.removeOne(Token.EPSILON);
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ctx = ctx.parentCtx;
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}
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if (following.contains(Token.EPSILON)) {
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expected.addOne(Token.EOF);
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}
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return expected;
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}
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}
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// Computes the set of input symbols which could follow ATN state number
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// {@code stateNumber} in the specified full {@code context}. This method
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@ -111,32 +137,6 @@ ATN.prototype.getDecisionState = function( decision) {
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// number {@code stateNumber}
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var Token = require('./../Token').Token;
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ATN.prototype.getExpectedTokens = function( stateNumber, ctx ) {
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if ( stateNumber < 0 || stateNumber >= this.states.length ) {
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throw("Invalid state number.");
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}
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var s = this.states[stateNumber];
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var following = this.nextTokens(s);
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if (!following.contains(Token.EPSILON)) {
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return following;
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}
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var expected = new IntervalSet();
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expected.addSet(following);
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expected.removeOne(Token.EPSILON);
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while (ctx !== null && ctx.invokingState >= 0 && following.contains(Token.EPSILON)) {
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var invokingState = this.states[ctx.invokingState];
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var rt = invokingState.transitions[0];
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following = this.nextTokens(rt.followState);
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expected.addSet(following);
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expected.removeOne(Token.EPSILON);
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ctx = ctx.parentCtx;
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}
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if (following.contains(Token.EPSILON)) {
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expected.addOne(Token.EOF);
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}
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return expected;
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};
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ATN.INVALID_ALT_NUMBER = 0;
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module.exports = ATN;
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