From 111ba8bf7c21bfa7abdbefd7f190772a4350e8a8 Mon Sep 17 00:00:00 2001 From: pelle Date: Tue, 6 Oct 2015 15:34:08 +0000 Subject: --- ...configuration_files_using_Template_Haskell.mdwn | 24 ++++++++++++++++++++++ 1 file changed, 24 insertions(+) create mode 100644 doc/forum/Embedding_configuration_files_using_Template_Haskell.mdwn (limited to 'doc/forum/Embedding_configuration_files_using_Template_Haskell.mdwn') diff --git a/doc/forum/Embedding_configuration_files_using_Template_Haskell.mdwn b/doc/forum/Embedding_configuration_files_using_Template_Haskell.mdwn new file mode 100644 index 00000000..11abe93b --- /dev/null +++ b/doc/forum/Embedding_configuration_files_using_Template_Haskell.mdwn @@ -0,0 +1,24 @@ +I want to replace configuration file contents using Propellor, but some configuration files are long so I want to keep them outside config.hs and without having to use quotation. I came up with this: + +``` +{-# LANGUAGE TemplateHaskell #-} +module Utility.Embed where + +import Language.Haskell.TH +import qualified Data.FileEmbed as FE + +sourceFile :: FilePath -> Q Exp +sourceFile path = return . AppE (VarE 'lines) =<< FE.embedStringFile path +``` + +Which can be used like this: + +``` +standardSystem :: HostName -> Host +standardSystem hn = host hn + & Apt.installed ["heimdal-clients"] + & "/etc/krb5.conf" `File.hasContent` + $(sourceFile "files/etc/krb5.conf") +``` + +What do you think, is this the right approach or should I just read source files with the IO monad? -- cgit v1.2.3