#!/bin/bash
#===============================================================================
#
#          FILE:  calculator.sh
# 
#         USAGE:  ./calculator.sh 
# 
#   DESCRIPTION:  Basically the bc command in -l mode with some extra functions defined
# 
#       OPTIONS:  ---
#  REQUIREMENTS:  ---
#          BUGS:  ---
#         NOTES:  ---
#        AUTHOR:  John Ryland (JR), (jryland@invertedlogic.com)
#       COMPANY:  InvertedLogic
#       VERSION:  1.0
#       CREATED:  21/05/2011
#      REVISION:  ---
#===============================================================================

LINE='
define factorial(x)
{
    if (x <= 1)
        return (1);
    return (factorial(x-1)*x);
}
define combinations(x,y)
{
    return factorial(x)/(factorial(y)*factorial(x-y));
}
define f(x)
{
    return factorial(x)
}
define com(x)
{
    return cominations(x)
}
'
while true
do
    echo "$LINE"
    read LINE
    if [ "$LINE" == "quit" ]
    then
        exit
    fi
done | bc -l