[mercury-users] Problem with mmake

[Richard A. O'Keefe]

	On 31-May-2001, Richard A. O'Keefe <ok at atlas.otago.ac.nz> wrote:
	> 	
	> 	(We could provide an environment variable, called say
	> 	MERCURY_DEFAULT_OPTIONS, which could be used to override this
	> 	for people who prefer to stick with --no-use-subdirs as the default.)
	> 	
	> ARRGH!  Not *another* environment variable!
	> 
	> The number of environment variables that a software system may reasonable
	> demand is ONE.
	
	Well, no-one would be *demanding* that you use this environment variable;
	it's [sic] use would be entirely optional.
	
Oh?  You mean people could get the effect they wanted without using it?

	> If it needs more configuration stuff, let that be in a file
	> and let the unique environment variable point to it.
	
	Why would that be an improvement?

Because it would only be one environment variable.
	
	Putting stuff in a configuration file would make
	it more difficult to selectively override different
	parts of the configuration for different processes.
	
I can't imagine why.  That isn't true for CSS or SGML catalogues or
shell-based configuration files or .mailrc or _anything_ much that has
an 'include' or 'source' feature.  In fact, it would be far *easier* to
override different aspects for different processes if you could set up
several "style" files and should point to the right one with a single
environment variable instead of having to hack lots of them.

	If we made it a command-line option to the program being executed,
	it would have to at very least have a long name (to avoid clashing
	with the option names for the program itself), so the repetitive typing
	problem would still arise.
	
Ah, Quintus Prolog and GHC both addresses the issue of having options
for the run-time system AND options for the applicatino in the same
command line.  It's a path that has been much trodden by other designers
as well, and does *not* require long option names.

--------------------------------------------------------------------------
mercury-users mailing list
post:  mercury-users at cs.mu.oz.au
administrative address: owner-mercury-users at cs.mu.oz.au
unsubscribe: Address: mercury-users-request at cs.mu.oz.au Message: unsubscribe
subscribe:   Address: mercury-users-request at cs.mu.oz.au Message: subscribe
--------------------------------------------------------------------------