Matthew Elder wrote:
{-# LANGUAGE CPP #-} main = putStrLn (__FILE__ ++ ":" ++ show __LINE__)
This outputs: test.hs:2
Unfortunately, if your file is in a hierarchy of folders, this flat file name doesn't give much context. Is there a macro to find out the current module? IE if I had a module Foo.Bar.Car.MyModule, I would like to be able to output something like this on error: Foo.Bar.Car.MyModule:2
As mentioned by Claus, template-haskell offers a solution. But in some cases, this is an overkill; consider using Control.Exception.assert, it will provide module and line information without having to use CPP: myHead :: [a] -> a myHead (x:_) = x myHead [] = assert False undefined
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//Stephan -- Früher hieß es ja: Ich denke, also bin ich. Heute weiß man: Es geht auch so. - Dieter Nuhr