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Handle non-unique expected values of match failuers differently

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Before this commit, uniqueness was checked when addding the failure. Now
we make the entiries unique when generating the error report, saving a
little time when the parsing is successful. This does not increase the
benchmark numbers too much though.

Results of benchmark with 100 runs on V8:

  Before:  37.25 kB/s
  After:   37.41 kB/s
  Speedup: 0.241 %

Mozilla/5.0 (X11; U; Linux i686; en-US) AppleWebKit/534.3 (KHTML, like
Gecko) Chrome/6.0.472.63 Safari/534.3
This commit is contained in:
David Majda 2010-08-22 20:01:16 +02:00
parent b6288a8d9c
commit 2d38c5cab3
3 changed files with 32 additions and 49 deletions
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37
src/emitter.js
View file

@ -137,21 +137,6 @@ PEG.compiler.emitter = function(ast) {
" + '\"';",
" }",
" ",
/* This needs to be in sync with |contains| in utils.js. */
" function contains(array, value) {",
" /*",
" * Stupid IE does not have Array.prototype.indexOf, otherwise this",
" * function would be a one-liner.",
" */",
" var length = array.length;",
" for (var i = 0; i < length; i++) {",
" if (array[i] === value) {",
" return true;",
" }",
" }",
" return false;",
" }",
" ",
" function matchFailed(failure) {",
" if (pos < rightmostMatchFailuresPos) {",
" return;",
@ -162,25 +147,33 @@ PEG.compiler.emitter = function(ast) {
" rightmostMatchFailuresExpected = [];",
" }",
" ",
" if (!contains(rightmostMatchFailuresExpected, failure)) {",
" rightmostMatchFailuresExpected.push(failure);",
" }",
" }",
" ",
" ${parseFunctionDefinitions}",
" ",
" function buildErrorMessage() {",
" function buildExpected(failuresExpected) {",
" switch (failuresExpected.length) {",
" failuresExpected.sort();",
" ",
" var lastFailure = null;",
" var failuresExpectedUnique = [];",
" for (var i = 0; i < failuresExpected.length; i++) {",
" if (failuresExpected[i] !== lastFailure) {",
" failuresExpectedUnique.push(failuresExpected[i]);",
" lastFailure = failuresExpected[i];",
" }",
" }",
" ",
" switch (failuresExpectedUnique.length) {",
" case 0:",
" return 'end of input';",
" case 1:",
" return failuresExpected[0];",
" return failuresExpectedUnique[0];",
" default:",
" failuresExpected.sort();",
" return failuresExpected.slice(0, failuresExpected.length - 1).join(', ')",
" return failuresExpectedUnique.slice(0, failuresExpectedUnique.length - 1).join(', ')",
" + ' or '",
" + failuresExpected[failuresExpected.length - 1];",
" + failuresExpectedUnique[failuresExpectedUnique.length - 1];",
" }",
" }",
" ",

36
src/parser.js
View file

@ -32,20 +32,6 @@ PEG.parser = (function(){
+ '"';
}
function contains(array, value) {
/*
* Stupid IE does not have Array.prototype.indexOf, otherwise this
* function would be a one-liner.
*/
var length = array.length;
for (var i = 0; i < length; i++) {
if (array[i] === value) {
return true;
}
}
return false;
}
function matchFailed(failure) {
if (pos < rightmostMatchFailuresPos) {
return;
@ -56,10 +42,8 @@ PEG.parser = (function(){
rightmostMatchFailuresExpected = [];
}
if (!contains(rightmostMatchFailuresExpected, failure)) {
rightmostMatchFailuresExpected.push(failure);
}
}
function parse_grammar() {
var cacheKey = "grammar" + '@' + pos;
@ -3443,16 +3427,26 @@ PEG.parser = (function(){
function buildErrorMessage() {
function buildExpected(failuresExpected) {
switch (failuresExpected.length) {
failuresExpected.sort();
var lastFailure = null;
var failuresExpectedUnique = [];
for (var i = 0; i < failuresExpected.length; i++) {
if (failuresExpected[i] !== lastFailure) {
failuresExpectedUnique.push(failuresExpected[i]);
lastFailure = failuresExpected[i];
}
}
switch (failuresExpectedUnique.length) {
case 0:
return 'end of input';
case 1:
return failuresExpected[0];
return failuresExpectedUnique[0];
default:
failuresExpected.sort();
return failuresExpected.slice(0, failuresExpected.length - 1).join(', ')
return failuresExpectedUnique.slice(0, failuresExpectedUnique.length - 1).join(', ')
+ ' or '
+ failuresExpected[failuresExpected.length - 1];
+ failuresExpectedUnique[failuresExpectedUnique.length - 1];
}
}

4
src/utils.js
View file

@ -1,7 +1,3 @@
/*
* The code needs to be in sync with the code template in the compilation
* function for "action" nodes.
*/
function contains(array, value) {
/*
* Stupid IE does not have Array.prototype.indexOf, otherwise this function