Issue #43 - Customizable operation parse error

src/MatchResult.js

@@ -171,6 +171,31 @@ MatchFailure.prototype.getRightmostFailures = function() {
   return this._failures;
 };
 
+MatchFailure.prototype.getMessage = function(config) {
+  var source = this.state.inputStream.source;
+  if (typeof source !== 'string') {
+    return 'match failed at position ' + this.getRightmostFailurePosition();
+  }
+  var detail = 'Expected ' + this.getExpectedText();
+
+  // use default values if not defined
+  var includeSource = typeof config !== 'undefined' &&
+    typeof config.includeSource !== 'undefined' ?
+      config.includeSource : true;
+  var includeLineNumbers = typeof config !== 'undefined' &&
+    typeof config.includeLineNumbers !== 'undefined' ?
+      config.includeLineNumbers : true;
+
+  if (!includeSource) {
+    return getShortMatchErrorMessage(
+        this.getRightmostFailurePosition(),
+        this.state.inputStream.source,
+        detail);
+  }
+  return util.getOptionalLineAndColumnMessage(
+      source, this.getRightmostFailurePosition(), includeLineNumbers) + detail;
+};
+
 // Return a string summarizing the expected contents of the input stream when
 // the match failure occurred.
 MatchFailure.prototype.getExpectedText = function() {

src/Semantics.js

@@ -340,7 +340,7 @@ function parseSignature(signature, type) {
       signature,
       type === 'operation' ? 'OperationSignature' : 'AttributeSignature');
   if (r.failed()) {
-    throw new Error(r.message);
+    throw new Error(r.getMessage({includeSource: true, includeLineNumbers: true}));
   }
 
   return prototypeGrammarSemantics(r).parse();

src/util.js

@@ -93,7 +93,10 @@ exports.getLineAndColumn = function(str, offset) {
 
 // Return a nicely-formatted string describing the line and column for the
 // given offset in `str`.
-exports.getLineAndColumnMessage = function(str, offset /* ...ranges */) {
+
+exports.getOptionalLineAndColumnMessage = function(str, offset, includeLineNumbers /* ranges */) {
+
+  var _includeLineNumbers = typeof includeLineNumbers !== 'undefined' ? includeLineNumbers : true;
   var repeatStr = common.repeatStr;
 
   var lineAndCol = exports.getLineAndColumn(str, offset);
@@ -109,7 +112,11 @@ exports.getLineAndColumnMessage = function(str, offset /* ...ranges */) {
 
   // Helper for appending formatting input lines to the buffer.
   function appendLine(num, content, prefix) {
-    sb.append(prefix + lineNumbers[num] + ' | ' + content + '\n');
+    if (_includeLineNumbers) {
+      sb.append(prefix + lineNumbers[num] + ' | ' + content + '\n');
+    } else {
+      sb.append('  ' + content + '\n');
+    }
   }
 
   // Include the previous line for context if possible.
@@ -123,7 +130,7 @@ exports.getLineAndColumnMessage = function(str, offset /* ...ranges */) {
   // Start with a blank line, and indicate each range by overlaying a string of `~` chars.
   var lineLen = lineAndCol.line.length;
   var indicationLine = repeatStr(' ', lineLen + 1);
-  var ranges = Array.prototype.slice.call(arguments, 2);
+  var ranges = Array.prototype.slice.call(arguments, 3);
   for (var i = 0; i < ranges.length; ++i) {
     var startIdx = ranges[i][0];
     var endIdx = ranges[i][1];
@@ -135,7 +142,7 @@ exports.getLineAndColumnMessage = function(str, offset /* ...ranges */) {
 
     indicationLine = strcpy(indicationLine, repeatStr('~', endIdx - startIdx), startIdx);
   }
-  var gutterWidth = 2 + lineNumbers[1].length + 3;
+  var gutterWidth = _includeLineNumbers ? 2 + lineNumbers[1].length + 3 : 2;
   sb.append(repeatStr(' ', gutterWidth));
   indicationLine = strcpy(indicationLine, '^', lineAndCol.colNum - 1);
   sb.append(indicationLine.replace(/ +$/, '') + '\n');
@@ -146,3 +153,9 @@ exports.getLineAndColumnMessage = function(str, offset /* ...ranges */) {
   }
   return sb.contents();
 };
+
+exports.getLineAndColumnMessage = function(str, offset /* ...ranges */) {
+  var args = Array.prototype.slice.call(arguments);
+  args.splice(2, 0, true);
+  return exports.getOptionalLineAndColumnMessage.apply(this, args);
+};