The hgom package

[Tags:gpl, program]

The executable hgom takes a module consisting of several abstract datatypes declarations as an input and ouputs java classes. It is meant to mimic the java version of Gom:

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Versions 0.5.1, 0.5.2, 0.5.3, 0.6
Dependencies base (==4.*), containers (>=0.2), directory (>=, filepath (>=, Glob (>=0.5), HUnit (>=, mtl (>=, parsec (>=3.0.0), process (>=, QuickCheck (>=2), test-framework (>=0.2.4), test-framework-hunit (>=0.2.4), test-framework-quickcheck2 (>=0.2.5), wl-pprint (>=1.0) [details]
License GPL
Copyright (c) Paul Brauner 2009 (c) Emilie Balland 2009 (c) INRIA 2009
Author Paul Brauner and Emilie Balland
Maintainer Paul Brauner <>
Category Compilers/Interpreters
Home page
Uploaded Wed Mar 3 16:25:08 UTC 2010 by PaulBrauner
Distributions NixOS:0.6
Downloads 986 total (6 in the last 30 days)
0 []
Status Docs not available [build log]
All reported builds failed as of 2016-12-30 [all 7 reports]
Hackage Matrix CI


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Maintainer's Corner

For package maintainers and hackage trustees

Readme for hgom

Readme for hgom-0.5.2


An haskell clone of the original java Gom code generator.


To compile hgom, install cabal-install and type the following.

cabal configure
cabal build

The hgom binary is generated in dist/build/hgom.


cabal install

Generate developer documentation

By default, cabal generates no documentation since only the executable is exported. Developers still can generate the modules' documentation as follows.

cabal haddock --executables \
--html-location='$pkg/latest/doc/html' \

Only exported symbols are documented. Add --internal for unexported symbols documentation.

The documentation index is then dist/doc/html/hgom/hgom/index.html.

Running hgom

Run hgom --help to get some basic help. You can test the behaviour of hgom by running it as follows. Some examples are valid files, other ones demonstrate hgom error messages.

hgom examples/simple.gom
hgom examples/big.gom
hgom examples/many_errors.gom


The test suite is compiled only if the test flag is set. For instance, run

cabal configure -ftest
cabal build
./dist/build/hgom/hgom --test "-a n"


cabal install -ftest
hgom --test "-a n"

where n is the number of generated random inputs for each test case.

For other arguments to the --test option, try hgom --test "--help".

Code Coverage

Code coverage can be tested as follows.

cabal build --ghc-options "-fhpc -fforce-recomp"
cd test/coverage

The documentation is generated in test/coverage/html.


There is some benchmark in test/bench that generates bigger and bigger gom files and runs hgom and gom on them, measuring the gom/hgom ratio concerning the number of generated lines (using sloccount) and the elapsed time.

cd test/bench

It takes some time. The generated files can be plotted using gnuplot for instance.

Differences with gom


  • faster !
  • a far less permissive checker
  • smaller code, compiles much faster
  • almost 100% code coverage,
  • unit tests using QuickCheck, both on compiler data structures and generated code
  • regression tests for parser and checker
  • more things optional: visitable, checker, ...
  • toHaskell, makeRandom, depth and size methods generation (optional)
  • smaller code for some generated methods (string escaping factorized for instance)
  • faster code for some generated methods (less function calls, more constants)
  • faster parser (from*) methods: don't use an intermediate ATerm representation
  • pretty-printed generated code, optional compact (no indentation) option


  • no hooks !
  • no ant task
  • imports only builtins
  • generates no comments


  • slightly different command-line arguments syntax