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Changelog History

  • v0.10.0 Changes

    August 19, 2016

    Major Changes

    πŸ“œ Parsers can be generated in multiple module formats. The available
    0️⃣ formats are: CommonJS (the default), AMD, UMD, globals, and bare (not
    available from the command-line).

    The format can be specified using the format option of the peg.generate
    function or the --format option on the command-line.

    πŸ“œ It is also possible to specify parser dependencies using the dependencies
    option of the peg.generate function or the --dependency/-d option on
    the command-line. This is mainly useful for the UMD format, where the
    dependencies are translated into both AMD dependencies and CommonJS
    require calls.

    πŸ’» Browser version of PEG.js is now in the UMD format. This means it will try
    to detect AMD or Node.js/CommonJS module loader and define itself as a
    module. If no loader is found, it will export itself using a global

    πŸ’… API polishing. The peg.buildParser function was renamed to
    πŸ’» peg.generate. The global variable the browser version of PEG.js is
    available in when no loader is detected was renamed from PEG to peg.

    CLI improvements. There is new --output/-o command-line option which
    πŸ‘ allows to specify the output file. The old way of specifying the output file
    🚚 using a second argument was removed. To make room for the new -o option
    ⚑️ the old one (a shortcut for --optimize) was renamed to -O. All these
    πŸ”„ changes make PEG.js conform to traditional compiler command-line interface.

    It is now also possible to use - as a file name on the command-line (with
    the usual meaning of standard input/output).

    πŸ‘Œ Improved error messages. Both messages produced by PEG.js and generated
    πŸ“œ parsers were improved.

    Duplicate rule definitions are reported as errors.

    Duplicate labels are reported as errors.

    Minor Changes

    • πŸ”¦ Exposed the AST node visitor builder as peg.compiler.visitor. This is
      πŸ”Œ useful mainly for plugins which manipulate the AST.
    • πŸ”¦ Exposed the function which builds messages of exceptions produced by
      πŸ— generated parsers as SyntaxError.buildMessage. This is useful mainly for
      customizing these error messages.
    • The error and expected functions now accept an optional location
      parameter. This allows to customize the location in which the resulting
      syntax error is reported.
    • πŸ”¨ Refactored expectations reported in the expected property of exceptions
      πŸ“œ produced by generated parsers. They are no longer de-duplicated and sorted,
      their format changed to be more machine-readable, and they no longer contain
      human-readable descriptions.
    • The found property of exceptions produced by the error function is now
      set to null.
    • βœ‚ Removed access to the parser object in parser code via the parser
    • Made handling of optional parameters consistent with ES 2015. Specifically,
      passing undefined as a parameter value is now equivalent to not passing
      the parameter at all.
    • πŸ“‡ Renamed several compiler passes.
    • πŸ“œ Generated parsers no longer consider \r, \u2028, and \u2029 as
      πŸ†• newlines (only \n and \r\n).
    • Simplified the arithmetics example grammar.
    • Switched from first/rest to head/tail in PEG.js grammar and example
    • πŸ‘• Started using ESLint instead of JSHint and fixed various problems it found.
    • βž• Added contribution
    • βœ‚ Removed support for io.js.

    πŸ› Bug Fixes

    • πŸ›  Fixed bin/pegjs so that invoking it with one non-option argument which is
      an extension-less file doesn’t cause that file to be overwritten.
    • πŸ›  Fixed label scoping so that labels in expressions like (a:"a") or (a:"a" b:"b" c:"c") aren’t visible from the outside.
    • πŸ›  Fixed escaping of generated JavaScript strings & regexps to also escape DEL
    • πŸ›  Fixed the JSON example grammar to correctly handle characters with code
      points above U+10FF in strings.
    • πŸ›  Fixed multiple compatibility issues of tools/impact on OS X.
    • πŸ›  Fixed slow deduplication of expectation descriptions.

    Complete set of changes

  • v0.9.0 Changes

    August 30, 2015

    Major Changes

    • πŸ‘ Tracing support. Parsers can be compiled with support for tracing their
      progress, which can help debugging complex grammars. This feature is
      experimental and is expected to evolve over time as experience is gained.
      More details
    • Infinite loop detection. Grammar constructs that could cause infinite
      πŸ“œ loops in generated parsers are detected during compilation and cause errors.
    • πŸ‘Œ Improved location information API. The line, column, and offset
      πŸ“œ functions available in parser code were replaced by a single location
      function which returns an object describing the current location. Similarly,
      the line, column, and offset properties of exceptions were replaced by
      a single location property. The location is no longer a single point but a
      character range, which is meaningful mainly in actions where the range
      covers action’s expression.
      More details
    • πŸ‘Œ Improved error reporting. All exceptions thrown when generating a parser
      have associated location information. And all exceptions thrown by generated
      πŸ“œ parser and PEG.js itself have a stack trace (the stack property) in
      πŸ‘ environments that support Error.captureStackTrace.
    • Strict mode code. All PEG.js and generated parser code is written using
      🌐 JavaScript strict mode.

    Minor Changes

    • πŸ‘€ Labels behave like block-scoped variables. This means parser code can see
      labels defined outside expressions containing code.
    • Empty sequences are no longer allowed.
    • Label names can’t be JavaScript reserved words.
    • Rule and label names can contain Unicode characters like in JavaScript.
    • Rules have to be separated either by ; or a newline (until now, any
      whitespace was enough).
    • The PEG.js grammar and all the example grammars were completely rewritten.
      This rewrite included a number of cleanups, formatting changes, naming
      πŸ”„ changes, and bug fixes.
    • πŸ“œ The parser object can now be accessed as parser in parser code.
    • Location information computation is faster.
    • βž• Added support for Node.js >= 0.10.x, io.js, and Edge. Removed support for
      Node.js < 0.10.x.

    πŸ› Bug Fixes

    • πŸ›  Fixed left recursion detector which missed many cases.
    • πŸ›  Fixed escaping of U+0100β€”U+107F and U+1000β€”U+107F in generated code and
      error messages.
    • πŸ“œ Renamed parse and SyntaxError to peg$parse and peg$SyntaxError to
      mark them as internal identifiers.

    Complete set of changes

  • v0.8.0 Changes

    December 24, 2013

    Big Changes

    • ⚑️ Completely rewrote the code generator. Among other things, it allows optimizing generated parsers for parsing speed or code size using the optimize option of the PEG.buildParser method or the --optimize/-o option on the command-line. All internal identifiers in generated code now also have a peg$ prefix to discourage their use and avoid conflicts. [#35, #92]
    • Completely redesigned error handling. Instead of returning null inside actions to indicate match failure, new expected and error functions can be called to trigger an error. Also, expectation inside the SyntaxError exceptions are now structured to allow easier machine processing. [#198]
    • πŸ— Implemented a plugin API. The list of plugins to use can be specified using the plugins option of the PEG.buildParser method or the --plugin option on the command-line. Also implemented the --extra-options and --extra-options-file command-line options, which are mainly useful to pass additional options to plugins. [#106]
    • πŸ— Made offset, line and column functions, not variables. They are now available in all parsers and return lazily-computed position data. Removed now useless trackLineAndColumn option of the PEG.buildParser method and the --track-line-and-column option on the command-line.
    • βž• Added a new text function. When called inside an action, it returns the text matched by action's expression. [#131]
    • βž• Added a new $ operator. It extracts matched strings from expressions.
    • The ? operator now returns null on unsuccessful match.
    • Predicates now always return undefined.
    • πŸ“œ Replaced the startRule parameter of the parse method in generated parsers with more generic options parameter. The start rule can now be specified as the startRule option. The options parameter can be also used to pass custom options to the parser because it is visible as the options variable inside parser code. [#37]
    • πŸ— The list of allowed start rules of a generated parser now has to be specified explicitly using the allowedStartRules option of the PEG.buildParser method or the --allowed-start-rule option on the command-line. This will make certain optimizations like rule inlining easier in the future.
    • βœ‚ Removed the toSource method of generated parsers and introduced a new output option of the PEG.buildParser method. It allows callers to specify whether they want to get back the parser object or its source code.
    • πŸ“¦ The source code is now a valid npm package. This makes using development
      πŸ”– versions easier. [#32]
    • ⚑️ Generated parsers are now ~25% faster and ~62%/~3% smaller (when optimized for size/speed) than those generated by 0.7.0.
    • Requires Node.js 0.8.0+.

    Small Changes

    • πŸ“œ bin/pegjs now outputs just the parser source if the value of the --export-var option is empty. This makes embedding generated parsers into other files easier. [#143]
    • πŸ”„ Changed the value of the name property of PEG.GrammarError instances from β€œPEG.GrammarError” to just β€œGrammarError”. This better reflects the fact that PEG.js can get required with different variable name than PEG.
    • Setup prototype chain for PEG.GrammarError correctly.
    • πŸ“œ Setup prototype chain for SyntaxError in generated parsers correctly.
    • πŸ›  Fixed error messages in certain cases with trailing input [#119]
    • πŸ›  Fixed code generated for classes starting with \^. [#125]
    • πŸ›  Fixed too eager proxy rules removal. [#137]
    • βž• Added a license to all vendored libraries. [#207]
    • βœ… Converted the test suite from QUnit to Jasmine, cleaning it up on the way.
    • πŸ‘· Travis CI integration.
    • πŸ›  Various internal code improvements and fixes.
    • πŸ›  Various generated code improvements and fixes.
    • πŸ›  Various example grammar improvements and fixes.
    • πŸ‘Œ Improved
    • Converted CHANGELOG to Markdown.
  • v0.7.0

    April 18, 2012
  • v0.6.2

    August 20, 2011
  • v0.6.1

    April 14, 2011
  • v0.6.0

    April 14, 2011
  • v0.5.1

    November 28, 2010
  • v0.5

    June 10, 2010