runghc examples

#21411 (closed)

a somewhat lengthy ticket closed Jul 4, 2022

Recently I took another look at the runghc code.

utils/runghc/Main.hs
utils/runghc/runghc.cabal.in

This could be rewritten not using literate Haskell.

$ sed 17q ghc/utils/runghc/Main.hs
{-# LANGUAGE CPP #-}
#include <ghcplatform.h>
-----------------------------------------------------------------------------
--
-- (c) The University of Glasgow, 2004
--
-- runghc program, for invoking from a #! line in a script.  For example:
--
--   script.lhs:
--      #!/usr/bin/env runghc
--      > main = putStrLn "hello!"
--
-- runghc accepts one flag:
--
--      -f <path>    specify the path
--
-- -----------------------------------------------------------------------------
$

rewrite

- --   script.lhs:
+ --   script.hs:
  --      #!/usr/bin/env runghc
- --      > main = putStrLn "hello!"
+ --      main = putStrLn "hello!"

e32a6e1f

This file looks as if it has an improperly written here document.

perhaps it's just an errant redirect symbol

$ ed -s ghc/utils/runghc/runghc.cabal.in <<<'10,20p'
    @runghc@ is a small wrapper program around GHC which allows the compiler
    to be used as a UNIX-style script interpreter. For instance,
    .
    @
    $ cat > Hi.hs
    \#!/usr/bin/env runghc
    main = putStrLn "hello!"
    $ chmod u+x Hi.hs
    $ ./Hi.hs
    hello!
    @
$

A properly written here document in a shell.

$ cat <<EOF > Hi.hs
> #!/usr/bin/env runghc
> main = putStrLn "hello!"
> EOF
$ 

The runghc.cabal.in extract appears to escape the # character.

@bgamari

Is escaping characters in @ @ sections documented somewhere?