(unknown charset) [BLACKBOX] Using IN for big comparsions (Was: Read-only IN parameters for all data types)

From: (unknown charset) Oleg N. Cher <"Oleg>
Date: Tue, 26 Feb 2008 00:02:36 +0200

----boundary-LibPST-iamunique-821160383_-_-
Content-type: text/plain

Dear Chris,

Our discussion about IN was long, and I must agree with you.
Eventually use of arguments IN carries the advantages.

Btw, I like language Pascal, in comparison with C, than:

Pascal:

IF x IN [0..31] AND y IN [0..23] THEN ... ;

C:

if((x >= 0) & (x <= 31) & (y >= 0) & (y <= 23)) ... ;

Pascal:

CASE inChar OF
 'a'..'z' : ...
 Enter : ...
 Space : ...

switch/case/break of language C does not provide so well
functionality, and we must use:

if((inChar >= 'a') & (inChar <= 'z')) ... ;
if(inChar = Enter) ... ;
if(inChar = Space) ... ;

Or, do you remember?

 case 0: case 1: case 2: case 3: case 4 ...

It as it seems to me, lacks of designing of language.
I'm not propose to use huge or big SETs in Oberon.
I propose this way of writing:

    IF a IN {0..1000} THEN ... END;

    Instead of

    IF (a >= 0) & (a <= 1000) THEN ... END;

Because such way of writing is represented to me more
readable, evident, understandable and natural.

At the same time any Oberon standards do not limit final
value of SET.

We can continue using of SETs by old way, but teach the compiler
of Component Pascal understand big comparisons as ocurrences
in a subset (without use of any set).
Eventually, a macroprocessor can make it even.

>> Instead of it I suggest to expand a way of use IN so:
>>
>> IF a IN {0..1000} THEN ... END;
>>
>> Current BlackBox realization does not accept such using of sets.
>> But such way of recording is good and evident. What will say?

>>
>
>Sets are useful but large sets do suffer from hidden inefficiencies.
>However, the example does not demonstrate their usefulness well as the
>alternative is not too cumbersome:
>
> IF (a >= 0) & (a <= 1000) THEN ... END;
>
>If you wanted to code something like this however,
>
> IF a IN {'a', 'e', 'i', 'o', 'u'} THEN
>
>large sets might appear more attractive, but they are still not really
>necessary as there is another alternative.
>
>Oberon doesn't usually have several different ways of doing exactly the same
>thing. In practice, these sorts of complex tests often are more suited to a
>CASE statement than an IF statement. Consequently that is where you will
>find a lot of flexibility with subranges and collections e.g.
>
> CASE s[i] OF
> 'a', 'e', 'i', 'o', 'u':
> INC(vowels);
> INC(letters) |
> 'A', 'E', 'I', 'O', 'U':
> INC(vowels);
> INC(letters);
> INC(capitals) |
> 'b'..'d', 'f'..'h', 'j'..'n', 'p'..'t', 'v'..'z':
> INC(letters) |
> ...
>
>Apologies for the biased choice of alphabet ;-)
>
>Regards,
>Chris
= = = = = = = = = = = = = = = = = = = =
                        
P.S. Aubrey McIntosh, thank you for your letter. It's very good.


Oleg N. Cher,
Colossoft Research.
allot{([at]})nowhere.xy
2008-02-25

----
To unsubscribe, send a message with body "SIGNOFF BLACKBOX" to LISTSERV{([at]})nowhere.xy----boundary-LibPST-iamunique-821160383_-_-
Content-type: application/rtf
Content-transfer-encoding: base64
Content-Disposition: attachment; filename="rtf-body.rtf"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----boundary-LibPST-iamunique-821160383_-_---

Received on Mon Feb 25 2008 - 23:02:36 UTC