Path: utzoo!mnetor!uunet!husc6!sri-unix!quintus!pds
From: pds@quintus.UUCP (Peter Schachte)
Newsgroups: comp.sys.amiga
Subject: Re: The 1001 Paths
Message-ID: <781@sandino.quintus.UUCP>
Date: 16 Mar 88 22:24:08 GMT
Organization: Quintus Computer Systems, Mountain View, CA
Lines: 39


> Seems to me like the "set" command is the ideal way to deal with the idea
> of multiple possible paths to any particular file. Manx supplies one with
> their compiler, and ARP contains a (much, much smaller) freely redistributable
> set command which is compatible with the Manx format.


> set FONTS=fonts:!fontdisk1:fonts/!wb:fonts/!dpaint:fonts/

There are two problems with this approach, relative to having path assigns
like this:

    assign FONTS fonts:, fontdisk1:fonts, wb:fonts, dpaint:fonts

Firstly, using "set" means that only the programmer has the power to
create a path.  The PROGRAMMER can say he will search $FONTS for the
desired font.  But the USER cannot say, for example, that a compiler
should look for includes in $INCLUDE, or that shell scripts are kept in
$S. And an existing program that looks in FONTS:  and doesn't know about
$FONTS won't search my font path.  We have a nice existing mechanism for
specifying "virtual directories."  We can extend it to cover paths, too,
and this would solve the path problem in an upward-compatible way.  Thus
ANY filename could be a path specification.  There's lots of power
there!  Much more than only allowing programmers to decide when paths
will be searched!  Of course, if you have a syntax for file names that
includes expanding path variables, and any attempt to open a file will
respect the path, then this complaint goes away.  Is that what you're
suggesting?

> and write a little parse routine to search all locations for any given file.

And this is my second complaint about this approach.  Why should every
program have to know about paths?  By hiding this mess in open(), we
simplify every program that wants to handle paths, and give paths for
free to every program that doesn't want to bother with them.
-- 
-Peter Schachte
pds@quintus.uucp
...!sun!quintus!pds