From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from skinner.cs.wisc.edu ([128.105.1.19]) by archone.tamu.edu with SMTP id <18921>; Thu, 19 Dec 1991 19:50:01 -0600
From: dws@cs.wisc.edu (DaviD W. Sanderson)
Message-Id: <9112200140.AA20484@skinner.cs.wisc.edu>
Received: by skinner.cs.wisc.edu; Thu, 19 Dec 91 19:40:37 -0600
Subject: new fn index
To: rc@archone.tamu.edu
Date: Thu, 19 Dec 1991 19:40:36 -0600
X-Mailer: ELM [version 2.3 PL11]

Well, I stuck out my neck and Chris showed me how to eliminate
even the one use of an external command.  That'll teach me! :-)

#-------
# index - print the index of the given string in the given list.
# (0 if not there)
# If the string occurs more than once, the index of the last occurrence
# is printed.
#-------
fn index {	# str list
	str = $1 ans = () {
		shift
		while(~ $str $*)
		{
			#-------
			# count in unary
			# May as well keep track of what I'm shifting
			# (perhaps it will be useful in a different
			# version...).
			#-------
			ans=($ans $1)
			shift
		}
		echo $#ans
	}
}

index a (x y z)		# 0
index a (a y z)		# 1
index a (x a z)		# 2
index a (ax y a)	# 3
index '' (a '' b '')	# 4