[r6rs-discuss] Re: [Formal] formal comment (ports, characters, strings, Unicode)

From: Thomas Lord <lord>
Date: Fri Mar 16 18:28:57 2007

John Cowan wrote:
> Thomas Lord scripsit:
>
>
>> Example: I've used the CHAR type in a traditional lisp way: to
>> represent typed characters with "bucky bits" like
>> META-ALT-SUPER-X. I understand others have as well
>> and do you agree permitting at least /that/ would be a reasonable
>> compromise? If that example should be permitted that gives us at least
>> a loosening of the range restrictions.
>>
>
> If you want those, then introduce the type BUCKY-CHAR, a supertype of
> CHAR. Why not?

For example, what is a STRING?


> That way CHAR remains portable and you can work in
> BUCKY-CHARs and, if needed, BUCKY-STRINGS.
>
>

Why can't I write a procedure that, say, reverses a string-like
value which can be either a BUCKY-STRING or a STRING
and which is a strictly portable procedure using just the core
functionality for strings?



>> Example: Scheme has been used quite a few times, successfully,
>> in embedded systems (such as controlling small robots). Such
>> applications often need a small footprint and don't need, for
>> example, large Unicode property tables. If that's permitted, that
>> gives us a shrinking of the mandatory character set.
>>
>
> Fortunately, the property tables are needed only if the program
> imports (r6rs unicode) -- the base library doesn't have any
> procedures depending on Unicode properties.
>
>

Then that would be another regression from R5 in which the
standard character-case procedures were useful for programs
which (for example) use them to manipulate their own source.


-t
Received on Fri Mar 16 2007 - 18:38:12 UTC