1 What is DocTest
DocTest is a small program, that checks examples in Haskell source code comments. It is modeled after doctest for Python.
DocTest is available from Hackage. Install it by typing (on your Unix shell):
$ cabal install doctest
Below is a small Haskell module. The module contains source code comments. Those comments are examples from an interactive Haskell session and demonstrate how the module is used.
module Fib where -- | Compute Fibonacci numbers -- -- Examples: -- -- >>> fib 10 -- 55 -- -- >>> fib 5 -- 5 fib :: Int -> Int fib 0 = 0 fib 1 = 1 fib n = fib (n - 1) + fib (n - 2)
All comment lines following an expression denote the result of that expression. Result is defined by what an REPL(e.g. ghci) prints to
evaluating that expression.)
With DocTest you may check if the implementation satisfies the given examples, by typing (on your Unix shell):
$ doctest Fib.hs
You may produce Haddock documentation for that module with:
$ haddock -h Fib.hs -o doc/
DocTest is still experimental. You can find a reference to the public source repository at Hackage.
Patches are gladly welcome!