522 Commits (e4b558832781f7e09895d7a67b2d873ee838ca32)
 

Author SHA1 Message Date
David Majda e4b5588327 Plugin API: Split compiler passes into stages
The compiler passes are now split into three stages:

  * check -- passes that check for various error conditions

  * transform -- passes that transform the AST (e.g. to perform
    optimizations)

  * generate -- passes that are related to code generation

Splitting the passes into stages is important for plugins. For example,
if a plugin wants to add a new optimization pass, it can add it at the
end of the "transform" stage without any knowledge about other passes it
contains. Similarly, if it wants to generate something else than the
default code generator does from the AST, it can just replace all passes
in the "generate" stage by its own one(s).

More generally, the stages make it possible to write plugins that do not
depend on names and actions of specific passes (which I consider
internal and subject of change), just on the definition of stages (which
I consider a public API with to which semver rules apply).

Implements part of GH-106.
12 years ago
David Majda 76f5c88073 Plugin API: Implement the |plugins| option for |PEG.buildParser|
The |plugins| option allows users to use plugins that change how PEG.js
operates.

A plugin is any JavaScript object with a |use| method. After the user
calls |PEG.buildParser|, this method is called for each plugin with the
following two parameters:

  * PEG.js config that describes used grammar parser and compiler
    passes used to generate the parser

  * options passed by user to |PEG.buildParser|

The plugin is expected to change the config as needed, possibly based on
the options passed by user. It can e.g. change the used grammar parser,
change the compiler passes (including adding its own), etc. This way it
can extend PEG.js in a flexible way.

Implements part of GH-106.
12 years ago
David Majda d02098eebe Plugin API: Implement the |passes| parameter for |PEG.compiler.compile|
The |passes| parameter will allow to pass the list of passes from
|PEG.buildParser|. This will be used by plugins. The old way via setting
the |appliedPassNames| property is removed.

Implements part of GH-106.
12 years ago
David Majda 3b3798fa39 Merge lib/compiler/passes.js into lib/compiler.js
It didn't make sense to have the passes in a separate file.
12 years ago
David Majda 02af83f9b4 s/subclass/peg$subclass/
The |subclass| function is not intended to be used by user code.
12 years ago
David Majda 4fe32cee8c Fix indentation 12 years ago
David Majda f985bd76ed Fix opcodes in comment in generate-bytecode.js 12 years ago
David Majda c7481d4da1 Test property presence in |utils.defaults| using |in|
This is more correct than comparing to |undefined|.
12 years ago
David Majda d3d4ace153 Move options handling from passes to |PEG.compiler.compile|
This eliminates some duplicate code.
12 years ago
David Majda 5942988f66 Remove the |startRule| property from the AST
It's redundant.
12 years ago
David Majda 3981433984 Fix too eager proxy rules removal
Fixes GH-137.
12 years ago
David Majda 5d00815b41 Improve |removeProxyRules| pass specs a bit 12 years ago
David Majda 549d052710 Make |GrammarError| require work also in the browser version
Fixes a bug from ac179cda7b (a fix for
GH-135).
12 years ago
David Majda d61fd1792d Fix JSHint errors
Fixes the following JSHint errors (which I think are JSHint bugs):

  spec/parser.spec.js: line 142, col 20, Bad for in variable 'key'.
  spec/generated-parser.spec.js: line 119, col 20, Bad for in variable 'key'.
12 years ago
David Majda 09f3f83e1c Merge pull request #135 from hyperpape/master
PEG.GrammarError is undefined in report-missing-rules and report-left-recursion
12 years ago
David Majda fe1ca481ab Code generator rewrite
This is a complete rewrite of the PEG.js code generator. Its goals are:

  1. Allow optimizing the generated parser code for code size as well as
     for parsing speed.

  2. Prepare ground for future optimizations and big features (like
     incremental parsing).

  2. Replace the old template-based code-generation system with
     something more lightweight and flexible.

  4. General code cleanup (structure, style, variable names, ...).

New Architecture
----------------

The new code generator consists of two steps:

  * Bytecode generator -- produces bytecode for an abstract virtual
    machine

  * JavaScript generator -- produces JavaScript code based on the
    bytecode

The abstract virtual machine is stack-based. Originally I wanted to make
it register-based, but it turned out that all the code related to it
would be more complex and the bytecode itself would be longer (because
of explicit register specifications in instructions). The only downsides
of the stack-based approach seem to be few small inefficiencies (see
e.g. the |NIP| instruction), which seem to be insignificant.

The new generator allows optimizing for parsing speed or code size (you
can choose using the |optimize| option of the |PEG.buildParser| method
or the --optimize/-o option on the command-line).

When optimizing for size, the JavaScript generator emits the bytecode
together with its constant table and a generic bytecode interpreter.
Because the interpreter is small and the bytecode and constant table
grow only slowly with size of the grammar, the resulting parser is also
small.

When optimizing for speed, the JavaScript generator just compiles the
bytecode into JavaScript. The generated code is relatively efficient, so
the resulting parser is fast.

Internal Identifiers
--------------------

As a small bonus, all internal identifiers visible to user code in the
initializer, actions and predicates are prefixed by |peg$|. This lowers
the chance that identifiers in user code will conflict with the ones
from PEG.js. It also makes using any internals in user code ugly, which
is a good thing. This solves GH-92.

Performance
-----------

The new code generator improved parsing speed and parser code size
significantly. The generated parsers are now:

  * 39% faster when optimizing for speed

  * 69% smaller when optimizing for size (without minification)

  * 31% smaller when optimizing for size (with minification)

(Parsing speed was measured using the |benchmark/run| script. Code size
was measured by generating parsers for examples in the |examples|
directory and adding up the file sizes. Minification was done by |uglify
--ascii| in version 1.3.4.)

Final Note
----------

This is just a beginning! The new code generator lays a foundation upon
which many optimizations and improvements can (and will) be made.

Stay tuned :-)
12 years ago
Justin Blank b58533ec2f Merge branch 'master' of https://github.com/dmajda/pegjs 12 years ago
Justin Blank ac179cda7b Fix ReferenceError in compiler passes.
Previously, the report-left-recursion and report-missing-rules passes
used PEG.GrammarError without requiring it, causing a ReferenceError.

Since requiring lib/peg.js would cause circular requirements, this
commit imports lib/grammar-error.js as GrammarError.

The bug was introduced in commit
4cda79951a.

Fixes GH-135.
12 years ago
David Majda bea6b1fde7 Implement the |text| function
When called inside an action, the |text| function returns the text
matched by action's expression. It can be also called inside an
initializer or a predicate where it returns an empty string.

The |text| function will be useful mainly in cases where one needs a
structured representation of the input and simultaneously the raw text.
Until now, the only way to get the raw text in these cases was to
painfully build it from the structured representation.

Fixes GH-131.
12 years ago
David Majda cab6521690 Test |offset|, |line| and |column| in the initializer
Add a test verifying that the |offset|, |line| and |column| functions
are visible and properly initialized inside the initializer.

See GH-132.
12 years ago
David Majda c54483bb17 Text nodes: Use text nodes in examples/javascript.pegjs 12 years ago
David Majda faaf9b6be1 Text nodes: Use text nodes in examples/css.pegjs 12 years ago
David Majda d0dfe46550 Text nodes: Use text nodes in examples/json.pegjs 12 years ago
David Majda 9ec6b6aa57 Text nodes: Use text nodes in examples/arithmetics.pegjs 12 years ago
David Majda f0a6bc92cc Text nodes: Use text nodes in PEG.js grammar 12 years ago
David Majda 5e146fce38 Text nodes: Implement text nodes
Implement a new syntax to extract matched strings from expressions. For
example, instead of:

  identifier = first:[a-zA-Z_] rest:[a-zA-Z0-9_]* { return first + rest.join(""); }

you can now just write:

  identifier = $([a-zA-Z_] [a-zA-Z0-9_]*)

This is useful mostly for "lexical" rules at the bottom of many
grammars.

Note that structured match results are still built for the expressions
prefixed by "$", they are just ignored. I plan to optimize this later
(sometime after the code generator rewrite).
12 years ago
David Majda af20f024c7 Text nodes: Disallow the "$" character in identifiers
The "$" character will mark text nodes in the future.
12 years ago
David Majda 4e46a6e46e Rebuild src/parser.js (forgotten in the previous commit) 12 years ago
David Majda 28860e88df Position tracking: Cache position info computed by |line| and |column|
Cache the last reported position info. If the position advances, the
code uses the cache and only computes the differnece. If the position
goes back, the cache is simply dropped.
12 years ago
David Majda 3333cdd18d Position tracking: Kill the |trackLineAndColumn| option
Getting rid of the |trackLineAndColumn| simplifies the code generator
(by unifying two paths in the code).

The |line| and |column| functions currently always compute all the
position info from scratch, which is horribly ineffective. This will be
improved in later commit(s).
12 years ago
David Majda da8c455640 Position tracking: Make |offset|, |line| and |column| functions
This will allow to compute position data lazily and get rid of the
|trackLineAndColumn| option without affecting performance of generated
parsers that don't use position data.
12 years ago
David Majda da9ab1bf17 Remove "make build" from tools/impact
There is no "build" target anymore.

This was forgotten in 0519d7e3ce.
12 years ago
David Majda 203243b884 README.md: Add link to the Trello board 12 years ago
David Majda bc9a2528ef Add backslash forgotten in the previous commit 12 years ago
David Majda 1988110a28 Fix code generated for classes starting with "\^"
Before this commit, incorrect regexps were produced for classes starting
with "\^". For example, this grammar:

  start = [\^a]

didn't match "a" because the generated regexp inside the parser was
/^[^a]/, not /^[\^a]/ as it should be.

This commit fixes the issue by escaping "^" in |quoteForRegexpClass|.

Fixes GH-125.
12 years ago
David Majda ff819cc579 Fix whitespace 12 years ago
David Majda 05a6bad989 Kill the |toSource| method, introduce the |output| option
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.
12 years ago
David Majda 3629d880d3 Make sure the |options| param passed to passes is always an object
Pass code can be simpler as a result.
12 years ago
David Majda ee1a0b5810 Add compiled examples to .gitignore
Based on patch by Pavel Lang (GH-96).
12 years ago
David Majda dd2216da7e Fix versions of development dependencies
This ensures stable environment for development, CI, browser builds,
etc.
12 years ago
David Majda 51e126882b Assume development dependencies are installed locally
This is compatible with what "npm install" does and allows for isolated
development environment.
12 years ago
David Majda 32e372be92 package.json: Formatting 12 years ago
David Majda 0519d7e3ce Git repo npmization: Make the repo a npm package
Includes:

  * Moving the source code from /src to /lib.
  * Adding an explicit file list to package.json
  * Updating the Makefile.
  * Updating the spec and benchmark suites and their READMEs.

Part of a fix for GH-32.
12 years ago
David Majda 4cda79951a Git repo npmization: Compose PEG.js from Node.js modules
PEG.js source code becomes a set of Node.js modules that include each
other as needed. The distribution version is built by bundling these
modules together, wrapping them inside a bit of boilerplate code that
makes |module.exports| and |require| work.

Part of a fix for GH-32.
12 years ago
David Majda c6cf129635 Git repo npmization: Do not use @VERSION
When the Git repository will be a npm package, there will be no
preprocessing step and thus no @VERSION substitution. Let's get rid of
it.

Part of a fix for GH-32.
12 years ago
David Majda d742ca5dc6 Makefile: Small reordering
Define |PEGJS_VERSION| before it is used. While defining it after its
first use was OK technically, it made the code a tiny bit harder to
read.
12 years ago
David Majda a7584fa878 Rebuild src/parser.js (forgotten in the previous commit) 12 years ago
David Majda 277fb23411 Setup prototype chain for |SyntaxError| in generated parsers correctly 12 years ago
David Majda 143924357b Setup prototype chain for |PEG.GrammarError| correctly 12 years ago
David Majda 428fe294cf Change |PEG.GrammarError| name
Change the value of the |name| property of |PEG.GrammarError| instances
from "PEG.GrammarError" to just "GrammarError". This better reflects the
fact that PEG.js can get required under different name than "PEG".
12 years ago