Can't use both shebang line and #ifdef declarations in the same file.
I have an (admittedly awkward) script which can be compiled or interpreted.
If it's compiled, I want the full goodness. If it's interpreted, I want to run a "minimal" version (because if I don't have the compiled version, I probably don't have the required libraries either).
The following almost works:
module Main (main) where
#ifdef FANCY
import qualified System.Console.ANSI as Term
start = Term.setSGR [Term.SetColor Term.Foreground Term.Dull Term.Green]
end = Term.setSGR []
#else
start = return ()
end = return ()
#endif
main :: IO ()
main = do
start
putStrLn "hello world"
end
and then I can do:
$ runghc -cpp main.hs
hello world
^^ plain text
$ ghc -O -cpp -DFANCY main.hs
$ ./main
hello world
^^ green text (a.k.a "fancy")
I attempted to make this directly runnable by adding a shebang line of
{{{ #!/usr/bin/runghc -cpp }}}
But unfortunately that chokes with -cpp:
$ ghc -O -cpp -DFANCY main.hs
main.hs:1:0: error: invalid preprocessing directive #!
Trac metadata
Trac field | Value |
---|---|
Version | 7.0.4 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | Unknown/Multiple |
Architecture |