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sourcecode:
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module MakeFile ( MakeFile, MakeElement(..), SpecialTarget(..)
, showMakeFile ) where
import Data.List ( intercalate )
-------------------------------------------------------------------------
--- A make file consists of a list of make elements.
type MakeFile = [MakeElement]
--- A data type for the description of an element of a make file.
data MakeElement = DefineVariable String [String]
| Rule [SpecialTarget] String [String] [String]
| Comment String
| Empty
--- A data type to describe special targets.
data SpecialTarget = PHONY | NOTPARALLEL
deriving Show
--- Shows a `MakeFile` as a string in standard makefile syntax.
showMakeFile :: MakeFile -> String
showMakeFile = unlines . map showMakeElement
showMakeElement :: MakeElement -> String
showMakeElement Empty = ""
showMakeElement (Comment s) = "# " ++ s
showMakeElement (DefineVariable name values) =
name ++ " = " ++ intercalate " \\\n\t " (unwordsUpTo 70 values)
showMakeElement (Rule specials target prereqs actions) = unlines $
map (\s -> showSpecialTarget s ++ ": " ++ target) specials ++
[target ++ ": " ++ intercalate " \\\n\t " (unwordsUpTo 70 prereqs) ] ++
map ("\t"++) actions
showSpecialTarget :: SpecialTarget -> String
showSpecialTarget st = '.' : show st
--- Fill all words into lines up to the given maximal length.
unwordsUpTo :: Int -> [String] -> [String]
unwordsUpTo max words = fillWords 0 "" words
where
fillWords _ s [] = [s]
fillWords n s (w:ws) =
let nw = n + length w
in if nw < max || n==0 -- no line break if we are at the line begin
then fillWords (nw+1) (s ++ (if n==0 then "" else " ") ++ w) ws
else s : fillWords 0 "" (w:ws)
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