language-c

Analysis and generation of C code

https://visq.github.io/language-c/

LTS Haskell 24.18:0.10.0@rev:1
Stackage Nightly 2025-11-04:0.10.0@rev:1
Latest on Hackage:0.10.0@rev:1

See all snapshots language-c appears in

BSD-3-Clause licensed by AUTHORS
Maintained by [email protected]
This version can be pinned in stack with:language-c-0.10.0@sha256:a66b5876fdec5a1defa9df5527c8bec52fc911335d36ee9c4b45fa11b5badbb9,3781

Module documentation for 0.10.0

Used by 1 package in nightly-2025-11-04(full list with versions):
c2hs

Language.C

Language.C is a parser and pretty-printer framework for C11 and the extensions of gcc.

See http://visq.github.io/language-c/

C Language Compatibility

Currently unsupported C11 constructs:

  • static assertion 6.7.10 (_Static_assert)
  • generic selection 6.5.1.1 (_Generic)
  • _Atomic, _Thread_local
  • Universal character names

Currently unsupported GNU C extensions:

  • __auto_type
  • __builtin_offsetof char a[__builtin_offsetof (struct S, sa->f)
  • _Decimal32
  • Extended assembler __asm__ __volatile__ ("" : : : ); __asm__ goto ("" : : : : label);
  • __attribute__((packed)): types featuring this attribute may have an incorrect size or alignment calculated.

IEC 60559:

Since language-c-0.8, extended floating point types are supported (gcc 7 feature). Package maintainers may decide to disable these types (flag iecFpExtension) to work around the fact that the _Float128 type is redefined by glibc >= 2.26 if gcc < 7 is used for preprocessing:

  /* The type _Float128 exists only since GCC 7.0.  */
  # if !__GNUC_PREREQ (7, 0) || defined __cplusplus
  typedef __float128 _Float128;
  # endif

Examples

A couple of small examples are available in examples.

Testing

See test/README.

Changes

Changelog

0.10.0

  • Support for half-precision floating point __fp16, _Float16, and _Float16x.
  • Support for bfloat16 __bf16.
  • Support alignment specifier _Alignas in struct declatations.

0.9.4

  • Support happy-2.1.

0.9.3

  • Add support for __builtin_bit_cast to support clang toolchain, enabling builds with GHC 9.4+ on Windows.

0.9.2

  • Add support for 128 bit builtin integer types

0.9.1

  • Support parsing an empty list of clobbers after a colon in asm statements

0.9.0.2

  • Correct lower bound on GHC

0.9.0.1

  • Scrap dependency on syb

Thanks to @vmchale

0.9

  • Make Trav a monad transformer
  • Add runTravTWithTravState
  • Tests now use Cabal-3
  • Implement alignment calculation and correct size calculation
  • Add Show instance for Type
  • Add machine descriptions for x86_64 and armv7l
  • Small correction in output of prettyprinter
  • Allow zeros as line numbers in preprocessed directives

Thanks to @aweinstock314, @ersran9, @expipiplus1, @jkoppel, @trofi and @visq

Changes since 0.7.0

Wed May 23 07:08:02 2018 +0200

  • Support IEC 60559 types and literals. Closes #52.

Wed May 16 07:08:15 2018 +0200

  • introduce flag for optional IEC 60559 type support (see #43)

Wed May 16 06:36:04 2018 +0200

  • WIP: towards a complete Export (#51)

Thu Feb 22 13:22:50 2018 -0500

  • [syntax] GHC.Generics.Generic and Control.DeepSeq.NFData instances (#49) (.cabal) drop splitBase flag

Tue Feb 20 08:34:39 2018 +0300

  • Selectively hide Prelude.<>: GHC 8.4 compat (#45)

Tue Feb 20 00:09:16 2018 -0500

  • (Analysis) Minimal support for __float128 (#47)

Sat Nov 25 08:59:59 2017 +0100

  • Consider builtin_convertvector from #34 for pretty printing

Sat Nov 25 00:46:33 2017 -0600

  • add support for _Float128 (#41)

Changes since 0.6.0

Mon Jul 31 2017

  • Improve TypeCheck output (#31)

Sun Jul 30 2017

  • Add __float128 (fixes #33)

Mon Maz 22 2017

  • Support clang’s __builtin_convertvector (Fixes #34)

Wed Mar 8 2017

  • Move file and parent information to new datatype FilePosition for performance reasons

Changes since 0.5.0

Thu Feb 23 2017

  • Make gccParseCPPArgs grab the arg to -MF -MT and -MQ

Wed Feb 15 2017

  • In enums, allow multiple attribute specifiers per enumerator

Tue Feb 21 2017

  • Allow typedef redefinition if it denotes the same type

Tue Feb 21 2017

  • Change TypeDefRef to store Type, not Maybe Type

Tue Feb 14 2017

  • Parse (and ignore) Clang attribute((availability(id=major.minor.rev)))

Sun Sep 11 2016

  • Add __builtin_bswap32/64.

Wed Jun 22 2016

  • Add _Alignof to Lexer.x (fixes #7)

Mon Jun 27 2016

  • Updates for C11 (part 1)
  • _Nullable and _Nonnull support as well as Warnings/lint fixes provided by Anthony Cowley (https://github.com/acowley)

Wed Mar 16 2016

  • Consider storage specifier “ThreadSpec” for global and local declarations

Tue Mar 15 2016

  • Support C11 _NoReturn, genearlize is_inline to FunSpecs (Syntax) / FunAttrs (SemRep)

Changes since 0.4.3

Wed Mar 2 2016

  • Add direct base type BaseInt128 (complements previous __int128 patch) [email protected]

Sun Feb 28 2016

  • Parse gcc-specific __int128 type

Thu Dec 4 2014

Changes since 0.4.2

Sat Jan 11 2014

  • Allow unicode characters in string/char literals and filenames

Mon Oct 27 2014

  • macos-attributes

Tue Aug 13 2013

  • Do not derive Error instances for newtypes (type parameter has non-parametric role)

Mon Aug 12 2013

  • Fix bug caused by applying posFile to nopos (reported by Mikhail Sosonkin)

Changes since 0.4.1

Tue Mar 19 2013

  • TypeCheck: Return Left str instead of fail str (do not rely on MonadError instance of Either)
  • Improve printing of SUERefs and Ident

Thu Feb 28 2013

  • Fix parsing and printing of octal character escapes.

Tue Jun 12 2012

  • Export Annotated type class from AST module

Wed Aug 24 2012

  • Patch for alex-3.0

Changes 0.3.1 - 0.4.1

Tue Aug 16 2011:

  • Port to ghc-7.2

Fri Apr 15 2011: Alexander Bernauer [email protected]

  • Show instances (popular request) for AST types, DumpAst demo

Changes 0.3 - 0.3.1

Thu Aug 21 [email protected]

  • add aliases for exposed parsers, in order to document them

Fri Aug 15 [email protected]

  • Remove NameMap from Data.Name. We will do this right when neccessary.
  • Parser public API: expose parsers and the Parser Monad
  • ParserMonad: Return updated name supply when executing parser
  • Parser: Expose expression, statement, declaration and file parsers
  • Data: Add newNameSupply ~ (namesStartingFrom 0)

Thu Aug 14 17:13:29 CEST 2008 [email protected]

  • Add a utility function to create a “blank” set of cpp arguments.
  • Make that analysis traversal monad abstract.
  • Export the type synonym “Register” (and bump version)

Wed Aug 13 12:00:57 CEST 2008 [email protected]

  • add Data.Position: internalIdentAt

Old Changes

Mon Jun 9 23:12:46 CEST 2008 [email protected]

  • License switched to 3-clause BSD $