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Re: [Chicken-users] Minor problem with args egg


From: Jim Ursetto
Subject: Re: [Chicken-users] Minor problem with args egg
Date: Wed, 13 May 2015 22:31:46 -0500

> On May 13, 2015, at 11:55, Jim Ursetto <address@hidden> wrote:
> 
> #t does seem to make sense ... the existing behavior comes from the srfi-37 
> implementation which sets the value to #f for #:none args.  I could modify 
> the args egg to change #f to #t in this case; I don't think this would cause 
> any problems.  Will think it over tonight.
> 

In args 1.5.1, #:none options now return a value of #t instead of the srfi-37 
default of #f, so they are effectively booleans.  This would also set up the 
possibility for —no-xxxxxx options which set option ‘xxxxxx' to #f; naturally, 
that is not yet implemented.

#:optional options will still return #f when an argument is not provided, since 
it is not nice to explicitly test against #t to distinguish between argument 
provided and not.  Also, optional arguments should not be boolean in my 
opinion.  An argument value of #f allows you to implement a default of “1" by 
placing this in the body:

 (set! arg (or arg “1”))

Jim


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