native numeric conversions for zsh

convert.zsh

#!/usr/bin/zsh
#
# PROGRAM: convert.zsh
# AUTHOR: Luciano D. Cecere
# DATE: 2013

script=$(basename $0)
typeset -i2 bin=$2
typeset -i8 oct=$2
typeset -i16 hex=$2

function bin {
	if [ $bin = "2#0" ]; then
		usage
	else
		printf "%s\n" "$(echo $bin | sed 's/2#//g')"
	fi
}

function octal {
	if [ $oct = "8#0" ]; then
		usage
	else
	 	printf "%s\n" "$(echo $oct | sed 's/8#//g')"
	fi
}

function hex {
	if [ $hex = "16#0" ]; then
		usage
	else
	        printf "%s\n" "$(echo $hex | sed 's/16#//g')"
	fi
}

function usage {
	cat <<EOF

$script base conversion tool

usage:
	./$script [-option] base-10-number
Options:
	-b	binary
	-o	octal
	-h 	hexadecimal

EOF
exit 0
}

case $1 in
	-b)	bin ;;
	-o)	octal ;;
	-h)	hex ;;
	 *)	usage
esac