#!/bin/bash

# Copyright by
# Scott D. Anderson
# scott.anderson@acm.org
# Released under the GNU General Public License

# The TW software is fully contained in its directory tree: it doesn't
# insinuate itself into other parts of your computer.  However, compiling
# using the TW Makefile is annoying without an alias, so this script adds
# an alias to your login script

# This script assumes that it is called with the TWHOME directory as its first arg

# Note that aliases are shell-specific, so you have to *source* this
# script in the shell that you want to have the alias, not execute it.

# Can't exit in this script, because we are sourcing it!

if [ $# -eq 0 ]; then
    echo "Usage: source add-alias TWHOME"
else

    export TWHOME=$1
    echo "TWHOME is ${TWHOME}"

    alias make-tw="make -f ${TWHOME}/Makefile "

    # Add the environment variable and alias to the ~/.bashrc, so that
    # every new shell gets it.  Technically, the environment variable
    # should go in ~/.bash_profile, but this is fine and reduces the
    # number of files we are messing with.

    if [ ! -e ~/.bashrc ]; then
	echo 'export TWHOMEDIR=${TWHOME}\nalias make-tw="make -f ${TWHOME}/Makefile "' > ~/.bashrc
    else
	# checking with grep makes this idempotent, but it means that
	# erroneous aliases don't get over-written.
	if ! grep 'make-tw' ~/.bashrc > /dev/null ; then
	    echo "adding the alias"
	    echo alias make-tw="make -f ${TWHOME}/Makefile " >> ~/.bashrc
	else
	    echo "alias is already there."
	fi
    fi
# end the main enclosing if
fi