From 8376ef56580626e9c0f796d5b85b53a0a1c7d5f5 Mon Sep 17 00:00:00 2001 From: V3n3RiX Date: Sat, 14 Jul 2018 21:03:06 +0100 Subject: gentoo resync : 14.07.2018 --- dev-haskell/file-location/metadata.xml | 42 ++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) create mode 100644 dev-haskell/file-location/metadata.xml (limited to 'dev-haskell/file-location/metadata.xml') diff --git a/dev-haskell/file-location/metadata.xml b/dev-haskell/file-location/metadata.xml new file mode 100644 index 000000000000..fd1840e49f39 --- /dev/null +++ b/dev-haskell/file-location/metadata.xml @@ -0,0 +1,42 @@ + + + + + haskell@gentoo.org + Gentoo Haskell + + + Common debugging/error/exception functions that give file location information + + > $(err "OH NO!") + > + > main:Main main.hs:16:1 OH NO! + + Notice how it displays package:module file:line:character + It exposes the functions err (error), undef (undefined), and trc (Debug.Trace.trace). All of these behave the same as their normal counterpart but also spit out a location. + + Here is my favorite helper, debug, which is like trace but just show the value. + + > debug [1,2,3] + > + > DEBUG: [1,2,3] + > [1,2,3] + + And The Template Haskell version. + + > $(dbg) [1,2,3] + > + > DEBUG main:Main main.hs:1:3 [1,2,3] + > [1,2,3] + + Also there is a version of thrwIO that gives location information + > ($(thrwIO) $ AException) `catch` \e -> putStrLn ("Caught " ++ show (e :: AException)) + > + > Caught AException "main:Main test/main.hs:25:6" + + See module for a listing of all the functions with short descriptions, and the homepage for some more examples https://github.com/gregwebs/ErrorLocation.hs + + + gregwebs/FileLocation.hs + + -- cgit v1.2.3