Before this commit, |PEG.buildParser| always returned a parser object.
The only way to get its source code was to call the |toSource| method on
it. While this method worked for parsers produced by |PEG.buildParser|
directly, it didn't work for parsers instantiated by executing their
source code. In other words, it was unreliable.
This commit remvoes the |toSource| method on generated parsers and
introduces a new |output| option to |PEG.buildParser|. It allows callers
to specify whether they want to get back the parser object
(|options.output === "parser"|) or its source code (|options.output ===
"source"|). This is much better and more reliable API.
Before this commit, generated parser were able to start parsing from any
rule. This was nice, but it made rule code inlining impossible.
Since this commit, the list of allowed start rules has to be specified
explicitly using the |allowedStartRules| option of the |PEG.buildParser|
method (or the --allowed-start-rule option on the command-line). These
rules will be excluded from inlining when it's implemented.
While |process.openStdin| is not officially deprecated, it's no longer
documented and just using |process.stdin| and resuming it seems to be
the official way.
The previous default name was "exports.parser". This meant that to use
the generated parser in Node.js, you had to use code like this:
var parser = require("./my-cool-parser").parser;
parser.parse(...);
Now you can shorten it a bit:
var parser = require("./my-cool-parser");
parser.parse(...);
The shorter version makes sense since no other objects except the parser
are exported from the module.
The source code is now in the src directory. The library needs to be
built using "rake", which creates the lib/peg.js file by combining the
source files.
Before this change, the start rule was the one named "start" and there
was an option to override that. This is now impossible.
The goal of this change is to contain all information for the parser
generation in the grammar itself.
In the future, some override directive for the start rule (like Bison's
"%start") may be added to the grammar.
Similar issue exists on Windows too (they have symlinks since Vista), but I
could not find how to dereference symlinks from batch files, so I did not fix
it. I guess this does not matter much given how little the symlinks are used in
the Windows world.
Closes#1.
This and also speeds up the benchmark suite execution by 7.83 % on V8.
Detailed results (benchmark suite totals):
---------------------------------
Test # Before After
---------------------------------
1 26.17 kB/s 28.16 kB/s
2 26.05 kB/s 28.16 kB/s
3 25.99 kB/s 28.10 kB/s
4 26.13 kB/s 28.11 kB/s
5 26.14 kB/s 28.07 kB/s
---------------------------------
Average 26.10 kB/s 28.14 kB/s
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David Majda