with-mlb-dependencies

#!/bin/bash
#
# with-mlb-dependencies - run a (presumed) compiler command, while also
# dumping out a dependency file. Intended for Meson build integration.
#
# Chris Cannam, 2020. MIT licence

set -e

if [ -z "$1" ]; then
    myname=$(basename "$0")
    echo 1>&2
    echo "Usage: $myname <buildcommand> <buildargs>" 1>&2
    echo 1>&2
    echo "First runs the supplied build command with the supplied build arguments;" 1>&2
    echo "then scans the build arguments, locating the first argument that names an .mlb" 1>&2
    echo "or .sml file, and writes out the dependency list for that file to a" 1>&2
    echo "similarly-named .deps file in the same location." 1>&2
    echo 1>&2
    echo "Example: $myname mlton program.mlb" 1>&2
    echo 1>&2
    echo "The above example runs mlton with the argument program.mlb; if that was" 1>&2
    echo "successful, it then writes out a dependency file called program.deps," 1>&2
    echo "containing a list of the input files which the target program depends on," 1>&2
    echo "in Makefile dependency syntax." 1>&2
    echo 1>&2
    echo "This program also looks for the -o, -output, and -mlb-path-var options in the" 1>&2
    echo "build arguments and interprets them appropriately." 1>&2
    exit 2
fi

set -u

mydir=$(dirname "$0")
. "$mydir/smlbuild-include.sh"

arg=""
output=""
env_args=
expecting_pathvar=false
expecting_output=false
for x in "$@" ; do
    if [ "$expecting_pathvar" = "true" ]; then
        env_args="$env_args $(echo $x |sed 's/ /=/')"
        expecting_pathvar=false
    elif [ "$expecting_output" = "true" ]; then
        output="$x"
        expecting_output=false
    else
        case "$x" in
            *.mlb) arg="$x";;
            *.sml) arg="$x";;
            -mlb-path-var) expecting_pathvar=true;;
            -o) expecting_output=true;;
            -output) expecting_output=true;;
            *) ;;
        esac
        if [ -n "$arg" ]; then
            break
        fi
    fi
done

"$@" || exit 1

if [ -z "$output" ]; then
    output=$(get_outfile "$arg")
fi

deps="$output".deps

shift

env $env_args \
    "$mydir/mlb-dependencies" "$arg" | \
    sed 's|^[^:]*: |'"$output: "'|' \
        > "$deps"