Hello, that is very interesting. on top of that, this library also offers an "assert" function, which will throw an exception with location in the source code if the assert condition is false. so i will definitely consider this. i would really rather compiler support but... That's probably the next best thing. Emmanuel On 7.11.2012 8:51, Karol Samborski wrote:
Hi Emmanuel!
Have you looked at http://hackage.haskell.org/packages/archive/loch-th/0.2.1/doc/html/Debug-Tra... ? With the loch-th package you can write your own head function like this:
{-# LANGUAGE TemplateHaskell #-} module Main where
import Debug.Trace.LocationTH
myHead a = $check $ head a
and then something like myHead ([] :: [Char]) will print something like this: test: test.hs:21:12-17: Prelude.head: empty list
In docs there is another useful function $failure that is "a location-emitting error call".
Hope that helps.