#!/bin/rc

awk '
function hex(s,        base, r, n, i, k, c)
{
	base = 16;
	if(s ~ /^0[xX][0-9a-fA-F]+/)
		s = substr(str, 3);
	n = length(s)
  	r = 0
	for (i = 1; i <= n; i++) {
		c = tolower(substr(s, i, 1))
		k = index("0123456789abcdef", c) - 1;
		r = r * base + k
	}
     	return r
}

function mystrtonum(str0,        neg, base, str, r, n, i, k, c)
{
	base = 0;
	neg = 0;
	str = str0;
	if(str ~ /^\+/)
		str = substr(str, 2)
	if(str ~ /^-/){
		str = substr(str, 2)
		neg = 1
	}
	if(str ~ /^0[0-7]*$/)
		base = 8
	if(str ~ /^0[xX][0-9a-fA-F]+/){
		str = substr(str, 3);
		base = 16;
	}
	if(base != 0){
		n = length(str)
  		r = 0
		for (i = 1; i <= n; i++) {
			c = tolower(substr(str, i, 1))
			k = index("0123456789abcdef", c) - 1;
			r = r * base + k
		}
	}else if(str ~ /^[0-9]*([.][0-9]*)?([Ee][-+]?[0-9]+)?$/)
		r = str0 + 0
	else
		r = "NaN"
     	return r
}

function usage()
{
	print "usage: seq [-w] [-f fmt] min [inc] max" > "/fd/2"
	exit(1);
}

function EARGF()
{
	if(j + 1 < length(a))
		return substr(a, j+1, 100);
	i++;
	if(i >= ARGC)
		usage();
	return ARGV[i];
}

function args()
{
	for(i = 1; i < ARGC; i++){
		a = ARGV[i]
		if(a !~ /^-..*/)
			break;
		for(j = 2; j <= length(a); j++){
			c = substr(a, j, 1);
			if(c == "w")
				flagw = 1
			else if(c == "f"){
				format = EARGF()
				if(format !~ /\n$/)
					format = format "\n"
			}else
				usage()
		}
	}
	n = ARGC - i
	if(n != 2 && n != 3)
		usage()
	min = mystrtonum(ARGV[i++])
	incr = 1
	if(n == 3)
		incr = mystrtonum(ARGV[i++])
	max = mystrtonum(ARGV[i++])
}

function buildfmt()
{
	if(length(format) > 0)
		return;
	format = "%g\n";
	if(!flagw)
		return;
	maxw = 0;
	maxp = 0;
	for(val = min; val <= max; val += incr){
		buf = sprintf("%g", val)
		if(buf ~ /e/)
			return
		parts = split(buf, ary, "\.");
		w = length(ary[1]);
		p = length(ary[2]) + parts==2;
		if(w>maxw)
			maxw = w;
		if(p>maxp)
			maxp = p;
	}
	if(maxp > 0)
		maxw += maxp+1;
	format = sprintf("%%0%d.%df\n", maxw, maxp);
}

BEGIN{
	args();
	buildfmt()

	for(val = min;; val += incr){
		if(incr > 0 && val > max)
			break;
		if(incr < 0 && val < max)
			break;
		printf(format, val)
	}

	exit(0);
}' $*