Add location information to |GrammarError|

This means all errors thrown by |PEG.buildParser| now have associated
location information.

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

@@ -10,13 +10,13 @@ function reportInfiniteLoops(ast) {
   var check = visitor.build({
     zero_or_more: function(node) {
       if (asts.matchesEmpty(ast, node.expression)) {
-        throw new GrammarError("Infinite loop detected.");
+        throw new GrammarError("Infinite loop detected.", node.location);
       }
     },
 
     one_or_more: function(node) {
       if (asts.matchesEmpty(ast, node.expression)) {
-        throw new GrammarError("Infinite loop detected.");
+        throw new GrammarError("Infinite loop detected.", node.location);
       }
     }
   });

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

@@ -34,7 +34,8 @@ function reportLeftRecursion(ast) {
     rule_ref: function(node, visitedRules) {
       if (arrays.contains(visitedRules, node.name)) {
         throw new GrammarError(
-          "Left recursion detected for rule \"" + node.name + "\"."
+          "Left recursion detected for rule \"" + node.name + "\".",
+          node.location
         );
       }
 

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

@@ -8,7 +8,8 @@ function reportMissingRules(ast) {
     rule_ref: function(node) {
       if (!asts.findRule(ast, node.name)) {
         throw new GrammarError(
-          "Referenced rule \"" + node.name + "\" does not exist."
+          "Referenced rule \"" + node.name + "\" does not exist.",
+          node.location
         );
       }
     }

lib/grammar-error.js

@@ -1,9 +1,10 @@
 var classes = require("./utils/classes");
 
 /* Thrown when the grammar contains an error. */
-function GrammarError(message) {
+function GrammarError(message, location) {
   this.name = "GrammarError";
   this.message = message;
+  this.location = location;
 }
 
 classes.subclass(GrammarError, Error);

spec/unit/compiler/passes/report-infinite-loops.spec.js

@@ -3,13 +3,21 @@ describe("compiler pass |reportLeftRecursion|", function() {
 
   it("reports infinite loops for zero_or_more", function() {
     expect(pass).toReportError('start = ("")*', {
-      message: "Infinite loop detected."
+      message:  "Infinite loop detected.",
+      location: {
+        start: { offset:  8, line: 1, column:  9 },
+        end:   { offset: 13, line: 1, column: 14 }
+      }
     });
   });
 
   it("reports infinite loops for one_or_more", function() {
     expect(pass).toReportError('start = ("")+', {
-      message: "Infinite loop detected."
+      message:  "Infinite loop detected.",
+      location: {
+        start: { offset:  8, line: 1, column:  9 },
+        end:   { offset: 13, line: 1, column: 14 }
+      }
     });
   });
 

spec/unit/compiler/passes/report-left-recursion.spec.js

@@ -3,7 +3,11 @@ describe("compiler pass |reportLeftRecursion|", function() {
 
   it("reports direct left recursion", function() {
     expect(pass).toReportError('start = start', {
-      message: 'Left recursion detected for rule \"start\".'
+      message:  'Left recursion detected for rule \"start\".',
+      location: {
+        start: { offset:  8, line: 1, column:  9 },
+        end:   { offset: 13, line: 1, column: 14 }
+      }
     });
   });
 
@@ -12,7 +16,11 @@ describe("compiler pass |reportLeftRecursion|", function() {
       'start = stop',
       'stop  = start'
     ].join("\n"), {
-      message: 'Left recursion detected for rule \"start\".'
+      message:  'Left recursion detected for rule \"start\".',
+      location: {
+        start: { offset: 21, line: 2, column:  9 },
+        end:   { offset: 26, line: 2, column: 14 }
+      }
     });
   });
 

spec/unit/compiler/passes/report-missing-rules.spec.js

@@ -3,7 +3,11 @@ describe("compiler pass |reportMissingRules|", function() {
 
   it("reports missing rules", function() {
     expect(pass).toReportError('start = missing', {
-      message: 'Referenced rule "missing" does not exist.'
+      message:  'Referenced rule "missing" does not exist.',
+      location: {
+        start: { offset:  8, line: 1, column:  9 },
+        end:   { offset: 15, line: 1, column: 16 }
+      }
     });
   });
 });