Merge ast utils into Grammar class

lib/compiler/asts.js

@@ -1,102 +0,0 @@
-"use strict";
-
-const visitor = require( "./visitor" );
-
-// AST utilities.
-const asts = {
-    findRule( ast, name ) {
-
-        for ( let i = 0; i < ast.rules.length; i++ ) {
-
-            if ( ast.rules[ i ].name === name ) return ast.rules[ i ];
-
-        }
-
-        return void 0;
-
-    },
-
-    indexOfRule( ast, name ) {
-
-        for ( let i = 0; i < ast.rules.length; i++ ) {
-
-            if ( ast.rules[ i ].name === name ) return i;
-
-        }
-
-        return -1;
-
-    },
-
-    alwaysConsumesOnSuccess( ast, node ) {
-
-        let consumes;
-
-        function consumesTrue() {
-
-            return true;
-
-        }
-        function consumesFalse() {
-
-            return false;
-
-        }
-
-        function consumesExpression( node ) {
-
-            return consumes( node.expression );
-
-        }
-
-        consumes = visitor.build( {
-            rule: consumesExpression,
-            named: consumesExpression,
-
-            choice( node ) {
-
-                return node.alternatives.every( consumes );
-
-            },
-
-            action: consumesExpression,
-
-            sequence( node ) {
-
-                return node.elements.some( consumes );
-
-            },
-
-            labeled: consumesExpression,
-            text: consumesExpression,
-            simple_and: consumesFalse,
-            simple_not: consumesFalse,
-            optional: consumesFalse,
-            zero_or_more: consumesFalse,
-            one_or_more: consumesExpression,
-            group: consumesExpression,
-            semantic_and: consumesFalse,
-            semantic_not: consumesFalse,
-
-            rule_ref( node ) {
-
-                return consumes( asts.findRule( ast, node.name ) );
-
-            },
-
-            literal( node ) {
-
-                return node.value !== "";
-
-            },
-
-            class: consumesTrue,
-            any: consumesTrue
-        } );
-
-        return consumes( node );
-
-    }
-};
-
-module.exports = asts;

lib/compiler/passes/calc-report-failures.js

@@ -1,6 +1,5 @@
 "use strict";
 
-const asts = require( "../asts" );
 const visitor = require( "../visitor" );
 
 // Determines if rule always used in disabled report failure context,
@@ -19,7 +18,7 @@ function calcReportFailures( ast, options ) {
     // always enabled
     const changedRules = options.allowedStartRules.map( name => {
 
-        const rule = asts.findRule( ast, name );
+        const rule = ast.findRule( name );
 
         rule.reportFailures = true;
 
@@ -42,7 +41,7 @@ function calcReportFailures( ast, options ) {
 
         rule_ref( node ) {
 
-            const rule = asts.findRule( ast, node.name );
+            const rule = ast.findRule( node.name );
 
             // This function only called when rule can report failures. If so, we
             // need recalculate all rules that referenced from it. But do not do

lib/compiler/passes/generate-bytecode.js

@@ -1,6 +1,5 @@
 "use strict";
 
-const asts = require( "../asts" );
 const op = require( "../opcodes" );
 const visitor = require( "../visitor" );
 const util = require( "../../util" );
@@ -643,7 +642,7 @@ function generateBytecode( ast ) {
 
         rule_ref( node ) {
 
-            return [ op.RULE, asts.indexOfRule( ast, node.name ) ];
+            return [ op.RULE, ast.indexOfRule( node.name ) ];
 
         },
 

lib/compiler/passes/generate-js.js

@@ -2,7 +2,6 @@
 
 "use strict";
 
-const asts = require( "../asts" );
 const js = require( "../js" );
 const op = require( "../opcodes" );
 
@@ -954,7 +953,7 @@ function generateJS( ast, options ) {
 
         parts.push( indent2( generateRuleHeader(
             "\"" + js.stringEscape( rule.name ) + "\"",
-            asts.indexOfRule( ast, rule.name )
+            ast.indexOfRule( rule.name )
         ) ) );
         parts.push( indent2( code ) );
         parts.push( indent2( generateRuleFooter(
@@ -1173,10 +1172,10 @@ function generateJS( ast, options ) {
 
             const startRuleIndices = "{ "
                 + options.allowedStartRules
-                    .map( r => r + ": " + asts.indexOfRule( ast, r ) )
+                    .map( r => r + ": " + ast.indexOfRule( r ) )
                     .join( ", " )
                 + " }";
-            const startRuleIndex = asts.indexOfRule( ast, options.allowedStartRules[ 0 ] );
+            const startRuleIndex = ast.indexOfRule( options.allowedStartRules[ 0 ] );
 
             parts.push( [
                 "  var peg$startRuleIndices = " + startRuleIndices + ";",

lib/compiler/passes/inference-match-result.js

@@ -1,7 +1,6 @@
 "use strict";
 
 const visitor      = require( "../visitor" );
-const asts         = require( "../asts" );
 const GrammarError = require( "../../grammar-error" );
 
 // Inference match result of the rule. Can be:
@@ -140,7 +139,7 @@ function inferenceMatchResult( ast ) {
         semantic_not: sometimesMatch,
         rule_ref( node ) {
 
-            const rule = asts.findRule( ast, node.name );
+            const rule = ast.findRule( node.name );
             node.match = inference( rule );
 
             return node.match;

lib/compiler/passes/report-infinite-recursion.js

@@ -1,7 +1,6 @@
 "use strict";
 
 const GrammarError = require( "../../grammar-error" );
-const asts = require( "../asts" );
 const visitor = require( "../visitor" );
 
 // Reports left recursion in the grammar, which prevents infinite recursion in
@@ -33,7 +32,7 @@ function reportInfiniteRecursion( ast ) {
 
                 check( element );
 
-                return ! asts.alwaysConsumesOnSuccess( ast, element );
+                return ! ast.alwaysConsumesOnSuccess( element );
 
             } );
 
@@ -53,7 +52,7 @@ function reportInfiniteRecursion( ast ) {
 
             }
 
-            check( asts.findRule( ast, node.name ) );
+            check( ast.findRule( node.name ) );
 
         }
     } );

lib/compiler/passes/report-infinite-repetition.js

@@ -1,7 +1,6 @@
 "use strict";
 
 const GrammarError = require( "../../grammar-error" );
-const asts = require( "../asts" );
 const visitor = require( "../visitor" );
 
 // Reports expressions that don't consume any input inside |*| or |+| in the
@@ -11,7 +10,7 @@ function reportInfiniteRepetition( ast ) {
     const check = visitor.build( {
         zero_or_more( node ) {
 
-            if ( ! asts.alwaysConsumesOnSuccess( ast, node.expression ) ) {
+            if ( ! ast.alwaysConsumesOnSuccess( node.expression ) ) {
 
                 throw new GrammarError(
                     "Possible infinite loop when parsing (repetition used with an expression that may not consume any input).",
@@ -24,7 +23,7 @@ function reportInfiniteRepetition( ast ) {
 
         one_or_more( node ) {
 
-            if ( ! asts.alwaysConsumesOnSuccess( ast, node.expression ) ) {
+            if ( ! ast.alwaysConsumesOnSuccess( node.expression ) ) {
 
                 throw new GrammarError(
                     "Possible infinite loop when parsing (repetition used with an expression that may not consume any input).",

lib/compiler/passes/report-undefined-rules.js

@@ -1,7 +1,6 @@
 "use strict";
 
 const GrammarError = require( "../../grammar-error" );
-const asts = require( "../asts" );
 const visitor = require( "../visitor" );
 
 // Checks that all referenced rules exist.
@@ -10,7 +9,7 @@ function reportUndefinedRules( ast, options ) {
     const check = visitor.build( {
         rule_ref( node ) {
 
-            if ( ! asts.findRule( ast, node.name ) ) {
+            if ( ! ast.findRule( node.name ) ) {
 
                 throw new GrammarError(
                     `Rule "${ node.name }" is not defined.`,
@@ -26,7 +25,7 @@ function reportUndefinedRules( ast, options ) {
 
     options.allowedStartRules.forEach( rule => {
 
-        if ( ! asts.findRule( ast, rule ) ) {
+        if ( ! ast.findRule( rule ) ) {
 
             throw new GrammarError( `Start rule "${ rule }" is not defined.` );
 

lib/parser/ast.js

@@ -1,5 +1,8 @@
 "use strict";
 
+const visitor = require( "../compiler/visitor" );
+const util = require( "../util" );
+
 class Node {
 
     constructor( type, location ) {
@@ -23,7 +26,110 @@ class Grammar extends Node {
         this.comments = comments;
         this.rules = rules;
 
+        this._alwaysConsumesOnSuccess = new AlwaysConsumesOnSuccess( this );
+
+    }
+
+    alwaysConsumesOnSuccess( node ) {
+
+        return this._alwaysConsumesOnSuccess.visit( node );
+
+    }
+
+    findRule( name ) {
+
+        return this.rules.find( rule => rule.name === name );
+
+    }
+
+    indexOfRule( name ) {
+
+        const rules = this.rules;
+
+        for ( let i = 0; i < rules.length; ++i ) {
+
+            if ( rules[ i ].name === name ) return i;
+
+        }
+
+        return -1;
+
     }
 
 }
 exports.Grammar = Grammar;
+
+/* ***************************** @private ***************************** */
+
+class AlwaysConsumesOnSuccess extends visitor.ASTVisitor {
+
+    constructor( ast ) {
+
+        super();
+        this.ast = ast;
+
+    }
+
+    choice( node ) {
+
+        return node.alternatives.every( this.visit, this );
+
+    }
+
+    sequence( node ) {
+
+        return node.elements.some( this.visit, this );
+
+    }
+
+    rule_ref( node ) {
+
+        return this.visit( this.ast.findRule( node.name ) );
+
+    }
+
+    literal( node ) {
+
+        return node.value !== "";
+
+    }
+
+}
+
+function consumesTrue() {
+
+    return true;
+
+}
+
+function consumesFalse() {
+
+    return false;
+
+}
+
+function consumesExpression( node ) {
+
+    return this.visit( node.expression );
+
+}
+
+util.extend( AlwaysConsumesOnSuccess.prototype, {
+
+    rule: consumesExpression,
+    named: consumesExpression,
+    action: consumesExpression,
+    labeled: consumesExpression,
+    text: consumesExpression,
+    simple_and: consumesFalse,
+    simple_not: consumesFalse,
+    optional: consumesFalse,
+    zero_or_more: consumesFalse,
+    one_or_more: consumesExpression,
+    group: consumesExpression,
+    semantic_and: consumesFalse,
+    semantic_not: consumesFalse,
+    class: consumesTrue,
+    any: consumesTrue,
+
+} );