A (new and improved) Xmas toy

[culliton@srg.srg.af.mil (Tom Culliton x2278)]

# Amazing what an extra half hour of thought will do to improve a piece
# of code.  I was fretting about the size of the function, because SCO
# Unix has limited environment space and managed to shave its size a bit
# and make it a little cleaner.

fn dirs { echo $D }
 
fn cd {
	if (! ~ $#* [01])
	{
		echo too many arguments
		return 1
	}
	switch ($1)
	{
	case -					# shorthand for -1
		cd $D(1)			# recursion
	case -[1-9] -[1-9][0-9]			# 1 -> 99 are valid
		cd $D(`{echo $1 | cut -c2-})	# recursion
	case -[0-9]*				# catch dumb stuff
		echo bad numeric argument
		return 1
	case *					# also handles no args case
		d=$D i=() {
			D = `{/bin/pwd}		# MRU moves to front
			for (i in $d)		# and eliminate duplicates
				if (! ~ $D $i)
					D = ($D $i)
			builtin cd $1		# actually go there
			# and fix the prompt
		}
	}
}