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Error handling: Build error message out of |SyntaxError|'s constructor
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It will be possible to create errors with user-supplied messages soon.
The |SyntaxError| class needs to be ready for that.

Implements part of pegjs#198.
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@dmajda @andreineculau
dmajda authored and andreineculau committed Apr 17, 2014
1 parent fca75d6 commit 00001fc
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Showing 2 changed files with 108 additions and 106 deletions.
117 changes: 59 additions & 58 deletions lib/compiler/passes/generate-javascript.js
View file
Original file line number Diff line number Diff line change
Expand Up @@ -684,71 +684,15 @@ module.exports = function(ast, options) {
' child.prototype = new ctor();',
' }',
'',
' function SyntaxError(expected, found, offset, line, column) {',
' function buildMessage(expected, found) {',
' function stringEscape(s) {',
' function hex(ch) { return ch.charCodeAt(0).toString(16).toUpperCase(); }',
'',
/*
* ECMA-262, 5th ed., 7.8.4: All characters may appear literally in a string
* literal except for the closing quote character, backslash, carriage
* return, line separator, paragraph separator, and line feed. Any character
* may appear in the form of an escape sequence.
*
* For portability, we also escape all control and non-ASCII characters.
* Note that "\0" and "\v" escape sequences are not used because JSHint does
* not like the first and IE the second.
*/
' return s',
' .replace(/\\\\/g, \'\\\\\\\\\')', // backslash
' .replace(/"/g, \'\\\\"\')', // closing double quote
' .replace(/\\x08/g, \'\\\\b\')', // backspace
' .replace(/\\t/g, \'\\\\t\')', // horizontal tab
' .replace(/\\n/g, \'\\\\n\')', // line feed
' .replace(/\\f/g, \'\\\\f\')', // form feed
' .replace(/\\r/g, \'\\\\r\')', // carriage return
' .replace(/[\\x00-\\x07\\x0B\\x0E\\x0F]/g, function(ch) { return \'\\\\x0\' + hex(ch); })',
' .replace(/[\\x10-\\x1F\\x80-\\xFF]/g, function(ch) { return \'\\\\x\' + hex(ch); })',
' .replace(/[\\u0180-\\u0FFF]/g, function(ch) { return \'\\\\u0\' + hex(ch); })',
' .replace(/[\\u1080-\\uFFFF]/g, function(ch) { return \'\\\\u\' + hex(ch); });',
' }',
'',
' var expectedDescs, expectedDesc, foundDesc, i;',
'',
' switch (expected.length) {',
' case 0:',
' expectedDesc = "end of input";',
' break;',
'',
' case 1:',
' expectedDesc = expected[0].description;',
' break;',
'',
' default:',
' expectedDescs = new Array(expected.length);',
'',
' for (i = 0; i < expected.length; i++) {',
' expectedDescs[i] = expected[i].description;',
' }',
'',
' expectedDesc = expectedDescs.slice(0, -1).join(", ")',
' + " or "',
' + expectedDescs[expected.length - 1];',
' }',
'',
' foundDesc = found ? "\\"" + stringEscape(found) + "\\"" : "end of input";',
'',
' return "Expected " + expectedDesc + " but " + foundDesc + " found.";',
' }',
'',
' function SyntaxError(message, expected, found, offset, line, column) {',
' this.message = message;',
' this.expected = expected;',
' this.found = found;',
' this.offset = offset;',
' this.line = line;',
' this.column = column;',
'',
' this.name = "SyntaxError";',
' this.message = buildMessage(expected, found);',
' }',
'',
' peg$subclass(SyntaxError, Error);',
Expand Down Expand Up @@ -931,13 +875,70 @@ module.exports = function(ast, options) {
' }',
' }',
'',
' function buildMessage(expected, found) {',
' function stringEscape(s) {',
' function hex(ch) { return ch.charCodeAt(0).toString(16).toUpperCase(); }',
'',
/*
* ECMA-262, 5th ed., 7.8.4: All characters may appear literally in a string
* literal except for the closing quote character, backslash, carriage
* return, line separator, paragraph separator, and line feed. Any character
* may appear in the form of an escape sequence.
*
* For portability, we also escape all control and non-ASCII characters.
* Note that "\0" and "\v" escape sequences are not used because JSHint does
* not like the first and IE the second.
*/
' return s',
' .replace(/\\\\/g, \'\\\\\\\\\')', // backslash
' .replace(/"/g, \'\\\\"\')', // closing double quote
' .replace(/\\x08/g, \'\\\\b\')', // backspace
' .replace(/\\t/g, \'\\\\t\')', // horizontal tab
' .replace(/\\n/g, \'\\\\n\')', // line feed
' .replace(/\\f/g, \'\\\\f\')', // form feed
' .replace(/\\r/g, \'\\\\r\')', // carriage return
' .replace(/[\\x00-\\x07\\x0B\\x0E\\x0F]/g, function(ch) { return \'\\\\x0\' + hex(ch); })',
' .replace(/[\\x10-\\x1F\\x80-\\xFF]/g, function(ch) { return \'\\\\x\' + hex(ch); })',
' .replace(/[\\u0180-\\u0FFF]/g, function(ch) { return \'\\\\u0\' + hex(ch); })',
' .replace(/[\\u1080-\\uFFFF]/g, function(ch) { return \'\\\\u\' + hex(ch); });',
' }',
'',
' var expectedDescs, expectedDesc, foundDesc, i;',
'',
' switch (expected.length) {',
' case 0:',
' expectedDesc = "end of input";',
' break;',
'',
' case 1:',
' expectedDesc = expected[0].description;',
' break;',
'',
' default:',
' expectedDescs = new Array(expected.length);',
'',
' for (i = 0; i < expected.length; i++) {',
' expectedDescs[i] = expected[i].description;',
' }',
'',
' expectedDesc = expectedDescs.slice(0, -1).join(", ")',
' + " or "',
' + expectedDescs[expected.length - 1];',
' }',
'',
' foundDesc = found ? "\\"" + stringEscape(found) + "\\"" : "end of input";',
'',
' return "Expected " + expectedDesc + " but " + foundDesc + " found.";',
' }',
'',
' var pos = Math.max(peg$currPos, peg$maxFailPos),',
' posDetails = peg$computePosDetails(pos),',
' found = pos < input.length ? input.charAt(pos) : null;',
'',
' cleanupExpected(peg$maxFailExpected);',
'',
' return new SyntaxError(',
' buildMessage(peg$maxFailExpected, found),',
' peg$maxFailExpected,',
' found,',
' pos,',
Expand Down
97 changes: 49 additions & 48 deletions lib/parser.js
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