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From: chris@pixutl.UUCP (chris)
Newsgroups: net.unix,net.unix-wizards
Subject: Re: Bourne shell modifications, past and future (long)
Message-ID: <10@pixutl.UUCP>
Date: Mon, 18-Nov-85 11:19:52 EST
Article-I.D.: pixutl.10
Posted: Mon Nov 18 11:19:52 1985
Date-Received: Wed, 20-Nov-85 00:35:16 EST
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Organization: Pixel Systems Inc., Woburn, Mass.
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> 
> > I think the most glaring difference between csh aliasing and
> > sys5 bourne shell functions is that the latter looks up builtins first.
> > This means you can't define functions that clash with shell commands.
> > On the other hand shell functions have a MUCH better syntax. Why not
> > move up the expansion of shell functions ahead of builtins at
> > the expense of not having recursive functions.
> 
> Very good question.  My guess is that either (a) it was easier
> to do it the other way, or (b) it would be considered a security
> problem in restricted shells.  Can DGK tell us why?

The main implementation problem in having functions overrule builtins is
that both builtins and functions share the same B-tree. If you wanted to
have a function with the same name as a builtin, you would have to save
it somewhere, add new flags, etc... all that adding overhead and
complexity.


Chris
-- 

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