# A Rail compiler written in Haskell
This is (or rather: will become) a compiler for the esoteric programming
language Rail, written in Haskell.
Contents of this repository
documentation contains additional documentation.
- The main documentation will be found in the code.
src contains the Rail compiler and editor (written in Haskell).
tests contains the hunit tests
integration-tests contains integration tests
- see section
tests for more information.
If you plan to contribute to the project,
make sure that your contribution does not break any tests and hlint is happy.
Though not applied consistently until now,
there are some things which would be really NICE to have:
- Set indetations to 2 spaces
- Remove trailing white spaces
- Do not retab/reformat other people's code, especially not in a commit which
contains some logical changes as well
- One logical change per commit
- Integrate hlint to your editor of
choice and try to stick to the suggestions it makes
- Would be cool, if lines are not longer than 80 characters
Module testing with HUnit
tests contains a
Main.hs file that runs an HUnit test with a list of test
functions. For each module
src/[module-name].hs of the compiler pipeline
exists a corresponding test file
tests/T[module-name].hs exporting a list of
test functions for the named module. In the
Main.hs file the list that is
tested by HUnit, is concatenated by the exported test lists of all test modules.
Integration tests are stored in
integration-tests in three subdirectories:
passing/ contains tests that are testing already implemented features and
that already passed before
failing/ contains tests that are testing already implemented features but
future/ contains tests that are testing functionality that will be added
in the future
Each test consists of two files. A rail program
[test-name].rail and an
The io-file specifies test cases, i.e. a set of inputs
with the expected corresponding outputs of the rail-program.
Input and output as well as the test cases themselves are separated by a hash
tag. If an input has more than one value, they are separated by a newline. Consider
a rail program adding two numbers and printing the result (without any newlines). A
corresponding io-file with two test cases could look as follows:
NOTE 1: printed newlines have to be stated explicitly. Consider a hello-world
Hello World\n (without any input). The io-file has to look
NOTE 2: The expected output is only tested against
stdout. If you want to test the output
stderr as well, you can add another section to a test case, separated by a single
This is the input.
This is the expected output on stdout.
This is the expected output on stderr.
Another stdout output.
NOTE 3: Lines containing only a single
# character always delimit sections as
described above. There is no way to escape them, sorry.
tests/integration_tests.sh is a script written in bash. It iterates over all
rail programs in
passing/, compiles each of them using the current version of
our rail compiler and retrieves runnable llvm-code, i.e. it already links it
with the stack implementation, etc. For each input/output value, it puts the
input into the llvm-binary and compares the actual output with the current
output. The result will be printed to stdout.
Dependencies / Building the Compiler
- Install cabal (package cabal-install in most distributions)
- Install llvm, versions llvm-3.3 and llvm-3.4 work.
- If you don't use llvm-3.4 you manually need to install the corresponding haskell bindings, i.e.:
cabal install llvm-general-18.104.22.168
- Switch to project folder
cabal install --enable-tests to install all dependencies and build the project
cabal test to run the tests
- Run the compiler with
dist/build/SWPSoSe14/SWPSoSe14 -c -i <Source.rail> -o output
- You still need to link the stack manually if you want to have executables:
llvm-link <compiled.ll> src/RailCompiler/*.ll -o executable
You can generate the compiler documentation using
cabal haddock --executables --haddock-options --ignore-all-exports from the root project directory.
Currently, there are several (long-lived) team branches and one main development branch,
master branch should always contain something that "works" to
some degree, i. e. it should never break.
All team branches are merged into the
master branch on a regular basis.
The following team branches exist. Except for
master, all branches not mentioned
here are to be considered (short-lived) feature branches.
gui: Contains everything with a graphical user interface, most notably the debugger
and the graphical Rail editor.
intertarget-code: Contains code for the backend, for intermediate code generation and
for code optimization.
preproc-lexer: Contains code for the preprocessor and lexer components.
synsem-analysis: Contains code for the syntactic/semantic analysis.
For additional information take a look at our wiki pages: https://github.com/SWP-Ubau-SoSe2014-Haskell/SWPSoSe14/wiki