#!/bin/bash
#
# haddock-i: list haddock's -i parameters.
#
# Copyright (c) 2015-2020 Rudy Matela.
# Distributed under the 3-Clause BSD licence.
#
# $ haddock-i <package1> <package2> ... <packageN>
#
# will print -i parameters necessary for haddock to link to Haddock
# documentation installed on your system, so you can:
#
# $ haddock-i base template-haskell | xargs haddock <files>
err() {
	echo "$@" > /dev/stderr
}

errxit() {
	err "$@"
	exit 1
}

iface-for() {
	ghc-pkg field $1 haddock-interfaces | sort -rV | head -1 | sed "s/.*: //"
}

html-for() {
	ghc-pkg field $1 haddock-html       | sort -rV | head -1 | sed "s/.*: //"
}

for pkg in "$@"
do
	iface=$(iface-for $pkg)
	html=$(html-for $pkg)
	[ -d "$html" -a -f "$iface" ] && echo "-i$html,$iface" || err "haddock-i: warning: could not find interface file for $pkg"
done