happy

Happy is a parser generator for Haskell https://www.haskell.org/happy/

Version on this page:1.19.5
LTS Haskell 9.5:1.19.7
Stackage Nightly 2017-09-20:1.19.7
Latest on Hackage:1.19.7
BSD2 licensed by Andy Gill and Simon Marlow
Maintained by Simon Marlow

Module documentation for 1.19.5

There are no documented modules for this package.

Happy

Happy is a parser generator for Haskell 98 (and later).

Build Status

  • https://www.haskell.org/happy/
  • http://hackage.haskell.org/package/happy

Happy is built using Cabal. First install GHC, then:

  $ cabal configure
  $ cabal build
  $ cabal install

Complete documentation can be found in the directory 'doc', in DocBook XML format. To format the documentation, the DocBook-Tools suite (see http://wiki.docbook.org/DocBookTools) provides all the bits & pieces you need. Alternatively, pre-formatted documentation is available from Happy's homepage (URL above).

The directory 'examples' contains some example parsers that use Happy.

For information on copying and distributing this program, see the file LICENSE in this directory.

Bugs should be reported at: https://github.com/simonmar/happy/issues

Happy Parsing!

Simon.

Changes

-----------------------------------------------------------------------------
1.19.7

* Fix misisng test suite files in the sdist

-----------------------------------------------------------------------------
1.19.6
* Manually generate Parser.hs using Makefile before sdist,
to fix bootstrapping problems with cabal sandboxes & new-build
* Documentation fixes
* Fixed GLR support
* new option -p/--pretty prints the grammar rules (only) to a file
* Added generation of additional type signatures to enable use
of typeclasses in monadic parsers.

-----------------------------------------------------------------------------
1.19.5
* fixes for GHC 7.10
* Code cleanups (thanks Index Int <vlad.z.4096@gmail.com>)

-----------------------------------------------------------------------------
1.19.4
* fix for GHC 7.10 (Applicative/Monad, #19, #21)

-----------------------------------------------------------------------------
1.19.3
* fix for GHC 7.2 (#16)

-----------------------------------------------------------------------------
1.19.2
* fixes for clang (XCode 5)

-----------------------------------------------------------------------------
1.19.1
* repackaged to build with GHC 7.7+

-----------------------------------------------------------------------------
1.19
* necessary changes to work with GHC 7.8

-----------------------------------------------------------------------------
1.18.10
* Fix build with GHC 7.6

-----------------------------------------------------------------------------
1.18.8
* Fix a packaging bug (cabal-install-0.10.2 didn't put the
Happy-generated files in the sdist)

-----------------------------------------------------------------------------
1.18.7

* Fix a bug in error handling when using %monad without %lexer

-----------------------------------------------------------------------------
Changes from version 1.17 to 1.18

* New feature: EBNF-style paramterized macros, thanks to
Iavor Diatchki.
* Works with Cabal 1.2, 1.4 and 1.6
* A few minor bugfixes

-----------------------------------------------------------------------------
Changes from version 1.16 to 1.17

* Cabal 1.2 is required
* Works with upcoming GHC 6.8.1
* Fix the 'parE' bug (poor error message for errors in the grammar)
* Some performance improvements to Happy itself

-----------------------------------------------------------------------------
Changes from version 1.15 to 1.16

* Switch to a Cabal build system: you need a recent version of Cabal
(1.1.6 or later). If you have GHC 6.4.2, then you need to upgrade
Cabal before building Happy. GHC 6.6 is fine.

* New %error directive

* New production forms: {%% .. } and {%^ .. }

* Added Attribute Grammar support, by Robert Dockins

-----------------------------------------------------------------------------
Changes from version 1.14 to 1.15

* New %expect directive
* the list of tokens passed to happyError now includes the current
token (not %lexer).
* added support for ambiguous grammars via Generalized LR parsing
* added %partial to indicate a parser that can return a result
before EOF is reached.

-----------------------------------------------------------------------------
Changes from version 1.13 to 1.14

* New meta-variable $> represents the rightmost token.

* Happy's OPTIONS pragma is merged with an existing one in
the grammar file, if any.

-----------------------------------------------------------------------------
Changes from version 1.11 to 1.13

* Support for newer versions of GHC (>= 5.04).

* Addition of an experimental flag: --strict.

-----------------------------------------------------------------------------
Changes from version 1.10 to 1.11

* tokens no longer have a default precedence - if you
want a token to have a precedence, you have to declare it.

* bugfix to templates for GHC on 64-bit platforms.

-----------------------------------------------------------------------------
Changes from version 1.9 to 1.10

* bugfixes, and minor performance improvements,

* most of the examples work again.

-----------------------------------------------------------------------------
Changes from version 1.8 to 1.9

* A grammar may now contain several entry points, allowing
several parsers to share parts of the grammar.

* Some bugfixes.

-----------------------------------------------------------------------------
Changes from version 1.6 to 1.8

* Parser table compression, and more efficient
table encoding when used with GHC. Large grammars
can now be compiled in much less time/space than
before using GHC.

* Yacc-style operator precedence, thanks to patches
from Hermann Oliveira Rodrigues <hermann@dcc.ufmg.br>
and Josef Svenningsson <josefs@cs.chalmers.se>.

* A debug option which causes the generated parser to
print tracing information at each step during parsing.

-----------------------------------------------------------------------------
Changes from version 1.5 to 1.6

* Now written in, and generates, Haskell 98.

* Several bug fixes.

* A new option, -c, generates parsers that use GHC's unsafeCoerce#
primitive to speed up parsing and cut down the binary size.
The -c option can only be used with the -g (GHC extensions) option.

* Parsers generated with the -g option will compile to smaller binaries
now - some sources of parser-bloat were identified and squished.

* Happy has a new Open Source license, based on the BSD license.

* A sample Haskell parser using Happy is included.

-----------------------------------------------------------------------------
Changes from version 1.2 to version 1.5

* Many bug fixes to the error recovery support, found by experimenting
with the Haskell grammar and layout.

* Happy is about 5 times faster on large examples, due to some
changes in the LALR(1) algorithms.

-----------------------------------------------------------------------------
Changes from version 0.9a to version 1.2

* Supports Haskell 1.4

* Lots of bugs fixed

* Performance: the parser generator is at least 20% faster, and
generated parsers should be faster due to the replacement of a
data type with a newtype.

* Simple error recovery: designed to be enough to implement the
Haskell layout rule.

* Revamped monad support: the monad can now be threaded through
the lexer, enabling passing of state between the parser and the
lexer (handy for the Haskell layout rule), and consistent error
handling.

* The %newline feature is removed, the same effect can be achieved
using the new monad support.

-----------------------------------------------------------------------------
Changes from version 0.8 to 0.9:

* Happy should be much faster than before.

* Generated parsers will be 5-10% smaller.

* Happy now compiles with ghc-0.26.

* Support for monadic parsers via %monad (see the documentation).

* New syntax: previously

f :: { <type> }
f : ...
| ...
etc.

can now be written

f :: { <type> }
: ...
| ...
etc.

(i.e. omit the extra 'f'. It was always ignored anyway :-)

* Miscellaneous bug fixes.
Depends on:
Used by 1 package:
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