#! /bin/ksh
##########################################################################
# Title      :	calc - calculate expressions
# Author     :	Heiner Steven <heiner.steven@odn.de>
# Date       :	1996-05-11
# Requires   :	bc, ksh
# Category   :	Desktop
# SCCS-Id.   :	@(#) calc	1.2 03/12/19
##########################################################################

PN=${0##*/}				# Program name
VER='1.2'

Scale=2					# Default precision

function Usage
{
    print -u2 "$PN - calculate expressions, $VER (hs '96)
usage: $PN [-p precision] [expr ...]
    -p set the precision to the given number of decimal digits

If no expressions are given on the command line, $PN reads
from stdin."
    exit 1
}

function Calc 
{
    set -e				# Terminate at errors
    print -p -r -- "$@"		# Write expression to "bc"

    # The result can take more than one line.
    # Make "bc" return a unique string as terminator
    # at the end of the calculation:

    print -p '"GNUELPF\n"'
    while read -p
    do
	[[ $REPLY = GNUELPF ]] && break
	print -- "$REPLY"
    done
    set +e
}

if (( $# > 0 ))
then					# Process options
    while getopts p:h Opt
    do
	case "$Opt" in
	    (p)	Scale="$OPTARG";;
	    (h)	Usage;;
	    (*)	Usage;;
	esac
    done
    shift OPTIND-1
fi

bc |&					# Start bc as co-process

[[ -n $Scale ]] && Calc "scale=$Scale"

if (( $# >= 1 ))
then					# Process arguments
    Calc "$@"
else					# Read from stdin
    while read Expr
    do
	Calc "$Expr"
    done
fi