#! /bin/ksh
##########################################################################
# Shellscript:	calc - calculate expressions
# Version    :	0.1 (beta)
# Author     :	Heiner Steven (heiner.steven@odn.de)
# Date       :	11.05.1996
# SCCS-Id.   :	$Id: calc,v 1.1.1.1 1999/06/15 19:29:05 heiner Exp $
##########################################################################

PN=${0##*/}				# Program name
VER='0.1 (beta)'

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 
{
    typeset Expr

    for Expr
    do
	set -e				# Terminate at errors
	print -p -- "$Expr"		# 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
    done
}

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