Wrapper script for ghc-mod for checking .ghc files

ghc-mod.sh

#! /usr/bin/env bash
#
# File:        ghc-mod.sh
# Description: Wrapper script allowing syntastic's ghc-mod checker to work with
#              .ghc files.
# Maintainer:  LCD 47 <lcd047 at gmail dot com>
# License:     This program is free software. It comes without any warranty,
#              to the extent permitted by applicable law. You can redistribute
#              it and/or modify it under the terms of the Do What The Fuck You
#              Want To Public License, Version 2, as published by Sam Hocevar.
#              See http://sam.zoy.org/wtfpl/COPYING for more details.

# The following is a rough translation of a Vim by @tarruda:
# https://github.com/tarruda/syntastic/commit/ab9d72ab33d055aa3c4025b5386f29268c91ad3a

# PATH=/usr/local/bin:/bin:/usr/bin

for last; do :; done

case "$last" in
    *.hsc)
        includes=
        for f in *.cabal *.buildinfo; do
            if [ -f "$f" ]; then
                includes="$includes $( awk '
                    tolower($1) == "include-dirs:" {
                        in_list = 1
                        $1 = ""
                    }

                    $1 ~ /:$/ {
                        in_list = 0
                        next
                    }

                    {
                        if (in_list) {
                            # XXX this breaks for quoted strings
                            split($0, dirs, / *, *| +/)
                            for (inc in dirs)
                                if (dirs[inc] != "")
                                    includes = includes " -I" dirs[inc]
                        }
                    }

                    END {
                        print includes
                    }
                ' "$f" )" || exit 1
            fi
        done

        # the .hs file has to be created in the same directory as the
        # source, to allow for relative include paths
        tf=$( mktemp -p "$( dirname "$last" )" "${0##*/}".$$.XXXXXXXX ) || exit 1

        # ghc-mod insists on a .hs extension
        hs="$tf".hs
        mv -f "$tf" "$hs" || exit 1
        trap 'rm -f "$hs"' 0 HUP INT QUIT TERM

        hsc2hs -o "$hs" $includes "$last" || exit 1

        # XXX "${@:1:$((${#}-1))}" is the list of positional arguments
        # without the last one; this is a bashism, no idea how to make
        # it portable
        ghc-mod "${@:1:$((${#}-1))}" "$hs"
        exit $?
        ;;

    *)
        exec ghc-mod "$@"
        ;;
esac