* Split 'consts' collection by content types into:
- literals: for literal expressions, like `"a"`
- classes: for character class expressions, like `[a]`
- expectations: for constants describing expected values when parse failed
- functions: for constants with function code
* Move any JavaScript code generation from 'generateBytecode' to 'generateJs'.
* Rename opcode 'MATCH_REGEXP' to 'MATCH_CLASS' (name reflects purpose, not implementation).
* Replace 'PUSH' opcode with 'PUSH_EMPTY_STRING' opcode because it is only used with empty strings
Before there used to be some internal utility methods for arrays and objects, but as the code base moved to ES5+ use case only, these were removed in favour of native alternatives, but most of these were only beneficial for arrays.
This commit add's common utility methods for objects, and also exposes these as they can be used by plugin developer's on the PEG.js AST.
* Optimization: do not generate unreachable calls |peg$fail| and constants for it (local to the rule).
* Optimization: do not generate unreachable calls |peg$fail| and constants for it (non-local to rule).
* Remove stack manipulations from FAIL opcode and rename FAIL to EXPECT
* Always save the expected values regardless of the match result of expression
* Remove unnecessary check for match result in the `named` node
* Collect and process expectations from predicates
This is related to my last commit. I've updated all the JavaScript files to satisfy 'eslint-config-futagozaryuu', my eslint configuration.
I'm sure I've probally missed something, but I've run all NPM scripts and Gulp tasks, fixed any bugs that cropped up, and updated some stuff (mainly related to generated messages), so as far as I can, tell this conversion is over (I know I've probally jixed it just by saying this ;P).
Before this commit, continuation lines of multi-line values in variable
declaration initializers were aligned with the variable name:
let foo = {
a: 5,
b: 6
};
This was highly irregular, maintenance intensive, and made declarations
look different from assignments.
This commit changes the indentation to be more regular and similar to
assignments:
let foo = {
a: 5,
b: 6
};
Use one var/let/const per variable, but only for initialized variables.
Uninitialized variables are still grouped into one var/let/const
declaration as I don't see any value in separating them. This approach
reflects the fact that initialized and uninitialized var/let/const
declarations are really two different things.
See #443.
Because arrow functions work rather differently than normal functions (a
bad design mistake if you ask me), I decided to be conservative with the
conversion.
I converted:
* event handlers
* callbacks
* arguments to Array.prototype.map & co.
* small standalone lambda functions
I didn't convert:
* functions assigned to object literal properties (the new shorthand
syntax would be better here)
* functions passed to "describe", "it", etc. in specs (because Jasmine
relies on dynamic "this")
See #442.
This is purely a mechanical change, not taking advantage of block scope
of "let" and "const". Minimizing variable scope will come in the next
commit.
In general, "var" is converted into "let" and "const" is used only for
immutable variables of permanent character (generally spelled in
ALL_CAPS). Using it for any immutable variable regardless on its
permanence would feel confusing.
Any code which is not transpiled and needs to run in ES6 environment
(examples, code in grammars embedded in specs, ...) is kept unchanged.
This is also true for code generated by PEG.js.
See #442.
Until now, expectations were constructed using object literals. This
commit changes the construction to use factory functions.
This change makes generated parsers slightly smaller because property
names don't have to be repeated many times and factory function calls
are more amenable to minifying.
Some numbers based on the aggregate size of parsers generated from
examples/*.pegjs:
Optimization Minified? Size before Size after Saving
------------------------------------------------------------
speed no 719066 716063 0.42%
speed yes 188998 180202 4.65%
size no 194810 197813 1.52%
size yes 108782 99947 8.12%
(Minification was done using "uglify --mangle --compress" with
uglify-js 2.4.24.)
Instead of pre-generating expectation descriptions when generating
parsers, generate them dynamically from structured information contained
in the expectations.
This change makes descriptions a presentation-only concept. It also
makes generated parsers smaller.
Changes:
* Remove the "value" property (it is replaced by other properties).
* Add the "parts", "inverted", and "ignoreCase" properties (which
allow more structured access to expectation data).
Changes:
* Rename the "value" property to "text" (because it doesn't contain
the whole value, which also includes the case sensitivity flag).
* Add the "ignoreCase" property (which was missing).
If the described class is case-sensitive, nothing changes.
If the described class is case-insensitive, its description doesn't
indicate that anymore. The indication was awkward and it was meaningful
only for parser users familiar with PEG.js grammar syntax (typically a
minority). For cases where case insensitivity indication is vital, named
rules can be used to customize the reporting.
Note that literal descriptions already ignore the case-sensitivity flag;
this commit only makes things consistent.
Simplify regexps that specify ranges of characters to escape with "\xXX"
and "\uXXXX" in various escaping functions. Until now, these regexps
were (mostly) mutually exclusive with more selective regexps applied
before them, but this became a maintenance headache. I decided to
abandon the exclusivity, which allowed to simplify these regexps (at the
cost of introducing an ordering dependency).
Before this commit, descriptions of literals used in error messages were
built by applying JavaScript string escaping to their values, making the
descriptions look like JavaScript strings. Descriptions of character
classes were built using their raw text. These approaches were mutually
inconsistent and lead to descriptions which were over-escaped and not
necessarily human-friendly (in case of literals) or coupled with details
of the grammar (in case of character classes).
This commit changes description building code in both cases and unifies
it. The intent is to generate human-friendly descriptions of matched
expressions which are clean, unambiguous, and which don't escape too
many characters, while handling special characters such as newlines
well.
Fixes#127.
I no longer think that using raw literal texts in error messages is the
right thing to do. The main reason is that it couples error messages
with details of the grammar such as use of single or double quotes in
literals. A better solution is coming in the next commit.
This reverts commit 69a0f769fc.
Labels in expressions like "(a:"a")" or "(a:"a" b:"b" c:"c")" were
visible to the outside despite being wrapped in parens. This commit
makes them invisible, as they should be.
Note this required introduction of a new "group" AST node, whose purpose
is purely to provide label scope isolation. This was necessary because
"label" and "sequence" nodes don't (and can't!) provide this isolation
themselves.
Part of a fix of #396.
Preform the following renames:
* |reportedPos| -> |savedPos| (abstract machine variable)
* |peg$reportedPos| -> |peg$savedPos| (variable in generated code)
* |REPORT_SAVED_POS| -> |LOAD_SAVED_POS| (instruction)
* |REPORT_CURR_POS| -> |UPDATE_SAVED_POS| (instruction)
The idea is that the name |reportedPos| is no longer accurate after the
|location| change (seea the previous commit) because now both
|reportedPos| and |currPos| are reported to user code. Renaming to
|savedPos| resolves this inaccuracy.
There is probably some better name for the concept than quite generic
|savedPos|, but it doesn't come to me.
Action and predicate code can now see variables defined in expressions
"above" them.
Based on a pull request by Bryon Vandiver (@asterick):
https://github.com/pegjs/pegjs/pull/180Fixes#316.
The TEXT instruction now replaces position at the top of the stack with
the input from that position until the current position. This is simpler
and cleaner semantics than the previous one, where TEXT also popped an
additional value from the stack and kept the position there.
Implement the following bytecode instructions:
* PUSH_UNDEFINED
* PUSH_NULL
* PUSH_FAILED
* PUSH_EMPTY_ARRAY
These instructions push simple JavaSccript values to the stack directly,
without going through constants. This makes the bytecode slightly
shorter and the bytecode generator somewhat simpler.
Also note that PUSH_EMPTY_ARRAY allows us to avoid a hack which protects
the [] constant from modification.
Futago-za Ryuu
Mingun
David Majda
Arlo Breault