lfe

#! /bin/sh
# -*- mode: shell-script; indent-tabs-mode: nil -*-
# Copyright (c) 2008-2024 Robert Virding
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# Follow symlinks to actual program and set env variables.  We have to
# cd to each directory following symlinks to handle relative symlinks.

follow_symlink () {
    cd "$(dirname "$1")" > /dev/null
    filename="$(basename "$1")"
    if [ -h "$filename" ]; then
        follow_symlink "$(readlink "$filename")"
    else
        echo "$(pwd -P)/$filename"
    fi
}

show_help () {
    echo "Usage: `basename $0` [flags] file [args]

    -h | --help              Print this help and exit
    -e | -eval \"sexp\"        Evaluates the given sexpr
    -- | -extra \"switches\"   Send misc configuration switches to the Erlang VM
    -prompt value            Set the LFE prompt to a user-supplied value
    -flag | +flag            Enables/disables configuration flags to be
                             used by the Erlang VM" >&2
}

SELF=$(follow_symlink "$0")
LFE_PROGNAME=$(echo "$0" | sed 's/.*\///') # Basically basename
LFE_BINDIR=$(dirname "$SELF")
LFE_ROOTDIR=$(dirname "$LFE_BINDIR")

export LFE_ROOTDIR
export LFE_BINDIR
export LFE_PROGNAME


# Stores static Erlang arguments and --erl (which is passed as is)
ERL=""

# Stores erl arguments preserving spaces/quotes (mimics an array)
erl_set () {
  eval "E${E}=\$1"
  E=$((E + 1))
}

# Checks if a string starts with prefix. Usage: starts_with "$STRING" "$PREFIX"
starts_with () {
  case $1 in
    "$2"*) true;;
    *) false;;
  esac
}

ERL_EXEC=erl
I=1
E=0
LENGTH=$#
set -- "$@" -extra

while [ $I -le $LENGTH ]; do
    # S counts to be shifted, C counts to be copied
    S=0
    C=0
    case "$1" in
	-e | -pa | -pz | -eval)
	    C=1
	    ;;
        -erl)
            S=2
            ERL="$ERL $2"
            ;;
        -sname | -name)
            S=2
            erl_set "$1"        #erl_set "$(echo "$1" | cut -c 2-)"
            erl_set "$2"
            ;;
        -cookie | -setcookie)
            S=2
            erl_set "-setcookie"
            erl_set "$2"
            ;;
        -sname | -name)
            erl_set "$1"        #erl_set "$(echo "$1" | cut -c 2-)"
            erl_set "$2"
            ;;
        *)
            while [ $I -le $LENGTH ]; do
                I=$((I+1))
                set -- "$@" "$1"
                shift
            done
            break
            ;;
    esac

    while [ $I -le $LENGTH ] && [ $C -gt 0 ]; do
        C=$((C - 1))
        I=$((I + 1))
        set -- "$@" "$1"
        shift
    done

    I=$((I + S))
    shift $S
done

echo "1 " "$@"

I=$((E - 1))
while [ $I -ge 0 ]; do
    eval "VAL=\$E$I"
    set -- "$VAL" "$@"
    I=$((I - 1))
done

echo "2 " "$@"

## set -- "-user" "lfe_init" "$@" "-extra"
set -- "-user" "lfe_init" "$@"

# The order of precedence for LFE libraries is as follows:
# 1) The LFE_ROOTDIR for the current bin/lfe being executed is unusurpable;
#    allowing anything else would leave LFE open to instabilities where it
#    could be executed with libraries of a different release.
# 2) A user/developer should be allowed to override anything else by updating
#    ERL_LIBS as they see fit.
# 3) A project's libraries (current directory) should be loaded automatically,
#    if they exist, but not override the previous two.
# 4) If a default library is installed in ~/.lfe/libs, then that will be added
#    last, in the event that the sought library is not picked up in any of the
#    other locations.
#
# Note that ERL_LIBS will find *either* an ebin subdir *or* lib subdir

# Find application ebin directories in lib if lib exists.

find_libs () {
    if [ -d "$1" ]; then
        echo $(find "$1" -maxdepth 1 -mindepth 1 -exec printf "%s:" {} \;)
    fi
}

# The following works for rebar and erl.mk
PROJ_LIBS=$(find_libs "./deps")
# The following works for rebar3
if [ -d "$REBAR_DEPS_DIR" ]; then
    # Use $REBAR_DEPS_DIR if set...
    R3_PROJ_LIBS=$(find_libs "$REBAR_DEPS_DIR")
else
    # ... otherwise provide a sensible default
    R3_PROJ_LIBS=$(find_libs "./_build/${REBAR_PROFILE:-default}/deps"):$(find_libs "./_build/${REBAR_PROFILE:-default}/lib")
fi
LFE_HOME_LIBS=$(find_libs "$HOME"/.lfe/lib)
ALL_LIBS="$LFE_ROOTDIR":"$ERL_LIBS":"$PROJ_LIBS""$R3_PROJ_LIBS""$LFE_HOME_LIBS"

if [ -n "$LFE_CLI_DRY_RUN" ]; then
    echo "ERL_LIBS=$ALL_LIBS" exec erl $ERL "$@"
else
    ERL_LIBS="$ALL_LIBS" exec erl $ERL "$@"
fi