#!zsh
#
# List numbers, eg.
#	enum 1 3	=> 1 2 3
# or	enum 3 1	=> 3 2 1
# or	enum 10 0 3	=> 10 7 4 1
# or	enum 0001 99 21  => 0001 0022 0043 0064 0085
#
# Suitable for use in eg. "for" loops, like
# 	for `enum 1 10` do ...
#

(( $# == 2 || $# == 3 )) || 
	{ print -u2 "Usage: $0 begin end [step]" ; return 1 }

integer begin=$1 end=$2 step=${3:-1}

if expr $1 : 0
then
	typeset -Z ${#1} n
else if expr $2 : 0
then
	typeset -Z ${#2} n
else
	integer n
fi 
fi > /dev/null

n=$begin

if (( n < end )) 
then
	while (( n <= end ))
	do
		print $n
		(( n += step ))
	done
else
	while (( n >= end ))
	do
		print $n
		(( n -= step ))
	done
fi