dmd 1.046 and 2.031 releases

[Derek Parnell]

On Mon, 06 Jul 2009 21:29:43 -0700, Walter Bright wrote:

> Derek Parnell wrote:
>> However, that aside, the syntax you have chosen will have a rational
>> explanation for its superiority. So can you explain in simple terms why 
>> 
>>     CaseLabelInt .. CaseLabelInt  eg. case 1: .. case 9:
>> 
>> is superior than
>> 
>>     case CaseRange:  eg. case 1 .. 9:
>> 
>> given that
>>   CaseLabelInt ==> case IntegerExpression :
>>   CaseRange    ==> IntegerExpression .. IntegerExpression
> 
> Because
> 
> 1.	case X..Y:
> 
> looks like
> 
> 2.	foreach(e; X..Y)
> 3.	array[X..Y]
> 
> yet the X..Y has a VERY DIFFERENT meaning. (1) is inclusive of Y, and 
> (2) and (3) are exclusive of Y.
> 
> Having a very different meaning means it should have a distinctly 
> different syntax.

Thank you, but now I am confused ... Andrei just got through lecturing us
that the meaning of punctuation is dependant upon context. So I think your
example must be more like ...

 Because
 
 1.	case X..Y:
 
 looks like
 
 2.	foreach(e; X..Y)
 3.	array[X..Y]
 4.     case X:..caseY:


 yet the X..Y has a VERY DIFFERENT meaning. (1) is inclusive of Y, and 
 (2) and (3) are exclusive of Y, and (4) is inclusive of Y ... oh, hang
on...

Sorry, but I'm just not getting the "VERY DIFFERENT" part yet. Right now, D
has ".." meaning exclude-end value (2. and 3.) AND it also has ".." meaning
include-end value (4.), depending on context. 

Ok, I admit that there is one subtle difference. Examples 2 and 3 are of
the form 

  IntExpression .. IntExpression

and example 4 is 

  CaseLabelInt .. CaseLabelInt

but seriously, people are not going to notice that. We see double-dot and
think "range". 

I know that this is not ever going to be changed so I'm not arguing that it
should. 

(One of the most frequent bugs I have in my D programs is that I forget
that X..Y excludes Y because it's not natural to me to see text that looks
like "the range X to Y" but means "the range X to Y-1".)

It seems that D would benefit from having a standard syntax format for
expressing various range sets;
 a. Include begin Include end, i.e. []
 b. Include begin Exclude end, i.e. [)
 c. Exclude begin Include end, i.e. (]
 d. Exclude begin Exclude end, i.e. ()

-- 
Derek Parnell
Melbourne, Australia
skype: derek.j.parnell