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To: rc@archone.tamu.edu
Subject: Re: a word about shift 
In-reply-to: malte's message of Wed, 11 Sep 91 13:10:34 -0400.
             <9109111710.AA06478@dahlie.techfak.uni-bielefeld.de> 
Date: Wed, 11 Sep 1991 17:29:08 -0000
From: Chris Siebenmann <cks@hawkwind.utcs.toronto.edu>
Message-Id: <91Sep11.132925edt.2708@hawkwind.utcs.toronto.edu>

 One can write a shift function that shifts an arbitrary list (except '*')
by whatever you want; in fact, I've attached my version at the end of this
message. Given that, I don't think we need to augment shift.

 I like shift giving you an error when you try to shift to far; people
who want other behaviors can write wrappers for it. I particularly dislike
options for what shift does; it should do *one* thing, always. See previous
arguments in the mailing list over options.

	- cks

# 'supershift' function for rc.
# usage:
#	sshift varname
#	sshift varname number
# shifts the list varname by number (default 1) positions.
fn sshift { if (~ $#* 1 ) { _sshift $1 1 $$1 } else { _sshift $1 $2 $$1 } }

# this function does most of the work.
# _sshift NAME COUNT LISTELEMS
# shift LISTELEMS COUNT items left, and assign the result to NAME.
fn _sshift { _vn=() { _vn=$1; shift; shift $1; shift; $_vn=$* } }