This is more traditional compiler interface. Its main advantage against
specifying the output file as a second argument (which is what bin/pegjs
used until now) is that input and output files can't be mixed up.
Part of #370.
This will make room for -o to mean --output instead of --optimize. Also,
-O is more traditional option name for describing optimization config
than -o.
Part of #370.
Improve the text stylistically and grammatically. Rewrite intro to nudge
people into the right direction and warn them about the usual fate of
spontaneous PRs.
The files were not really templates but instructions. These instructions
are already spelled-out in CONTRIBUTING.md and repeating them feels a
bit redundant.
If it turns out people don't read CONTRIBUTING.md when submitting issues
and pull requests, I'll probably restore the templates (likely in some
shorter/simpler form).
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.)
The "buildMessage" utility function, which was previously internal, is
now exposed as SyntaxError.buildMessage in generated parsers.
The motivation behind this is two-fold:
1. Building of a syntax error message is a responsibility of the
SyntaxError class, meaning the code should be placed there.
2. By exposing the message building code, parser users can use it to
generate customized error messages without duplicating PEG.js's code.
Note that helper functions inside "buildMessage" ("describeExpected",
"describeFound", etc.) currently aren't exposed. They may become exposed
in the future if there is enough demand.
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.
Before this commit, expectations were sorted and de-duplicated before
they were passed to "buildMessage" and exposed in the "expected"
property of syntax errors. This commit moves this processing into
"buildMessage" and rewrites it to process only expectation descriptions.
This means expectations exposed in the "expected" property are "raw"
(not sorted and de-duplicated).
This change will allow us to get rid of the "description" property of
expectations and compute descriptions dynamically from structured
information in the expectations. This will make descriptions a
presentation-only concept. It will also make generated parsers smaller.
Note that to keep expectations in the "expected" property sorted even
without the "description" property, some sorting scheme based on
structured information in the expectations would have to be devised,
which would complicate things with only a little benefit. Therefore I
chose to keep the expectations there "raw".
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).
Change how found strings are escaped when building syntax error
messages:
* Do not escape non-ASCII characters (U+0100-U+FFFF). They are
typically more readable in their raw form.
* Escape DEL (U+007F). It is a control character.
* Escape NUL (U+0000) as "\0", not "\x00".
* Do not use less known shortcut escape sequences ("\b", "\f"), only the
well-known ones ("\0", "\t", "\n", "\r").
These changes mirror expectation escaping changes done in
4fe682794d.
Part of work on #428.
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.
In most places, we talk about "generating a parser", not "building a
parser", which the function name should reflect. Also, mentioning a
parser in the name is not necessary as in case of a parser generator
it's pretty clear what is generated.
So far, PEG.js was exported in a "PEG" global variable when no module
loader was detected. The same variable name was also conventionally used
when requiring it in Node.js or otherwise referring to it. This was
reflected in various places in the code, documentation, examples, etc.
This commit changes the variable name to "peg" and fixes all relevant
occurrences. The main reason for the change is that in Node.js, modules
are generally referred to by lower-case variable names, so "PEG" was
sticking out when used in Node.js projects.
The wrapping functions are also generated by PEG.js, so the comment
should be above them to mark them as such. This shouldn't cause any
problems technically.
David Majda