[Haskell-cafe] haltavista - look for functions by example
Roel van Dijk
vandijk.roel at gmail.com
Sun Sep 19 13:41:21 EDT 2010
It got me thinking: if you combine this with the Arbitrary class 
of QuickCheck you can use it check if you have defined a function that
is "equal" to an already defined function.
Let's say I write the following function:
intMul ∷ Integer → Integer → Integer
intMul x 0 = 0
intMul x n = x + intMul x (n - 1)
No you can automatically apply this function to a list of 100
generated inputs to get a list of input output pairs. Feed this into
haltavista and it should tell you that you can replace your definition
with Prelude (*). While such an observation is certainly not a proof
it is still useful.
It would be a nice addition to a Haskell editor. Especially for those
new to the language.
1 - http://hackage.haskell.org/packages/archive/QuickCheck/2.3/doc/html/Test-QuickCheck-Arbitrary.html
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