Semicolons: mostly unnecessary?

[Pelle Månsson]

KennyTM~ wrote:
> On Oct 22, 09 21:36, Pelle Månsson wrote:
>> KennyTM~ wrote:
>>> On Oct 22, 09 21:12, Ary Borenszweig wrote:
>>>> KennyTM~ wrote:
>>>>> On Oct 22, 09 19:03, Pelle Månsson wrote:
>>>>>> KennyTM~ wrote:
>>>>>>> On Oct 22, 09 13:57, AJ wrote:
>>>>>>>> "KennyTM~"<kennytm at gmail.com> wrote in message
>>>>>>>> news:hbopns$125k$1 at digitalmars.com...
>>>>>>>>> On Oct 22, 09 12:29, AJ wrote:
>>>>>>>>>> "Adam D. Ruppe"<destructionator at gmail.com> wrote in message
>>>>>>>>>> news:mailman.228.1256181155.20261.digitalmars-d at puremagic.com...
>>>>>>>>>>> On Wed, Oct 21, 2009 at 09:25:34PM -0500, AJ wrote:
>>>>>>>>>>>> That's not D source code. Why do you keep trying to use English
>>>>>>>>>>>> text as
>>>>>>>>>>>> an
>>>>>>>>>>>> example?
>>>>>>>>>>>
>>>>>>>>>>> The logic behind all the arguments you make,
>>>>>>>>>>
>>>>>>>>>> That would be "all fine and dandy", but I'm not arguing about
>>>>>>>>>> anything.
>>>>>>>>>> (So
>>>>>>>>>> you must be arguing? About what?).
>>>>>>>>>>
>>>>>>>>>>> except for one, should apply
>>>>>>>>>>> equally well to English as it does to D.
>>>>>>>>>>
>>>>>>>>>> That's silly. There is no need to use the text of Shakespeare's
>>>>>>>>>> tragedies
>>>>>>>>>> to
>>>>>>>>>> allude to source code. There is no need and it is entirely
>>>>>>>>>> inappropriate
>>>>>>>>>> to
>>>>>>>>>> expand the context of the issue to other realms. The context is
>>>>>>>>>> (currently):
>>>>>>>>>> semicolons as statement terminators for single-statement lines.
>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> Cons:
>>>>>>>>>>>
>>>>>>>>>>> 1. Makes source code less comprehensible.
>>>>>>>>>>>
>>>>>>>>>>> Based on what? Because you say so?
>>>>>>>>>>
>>>>>>>>>> It's more to digest when it's not necessary. It's easier to
>>>>>>>>>> identify
>>>>>>>>>> something when it's in less intricate (read, plain) surroundings.
>>>>>>>>>>
>>>>>>>>>> <snipped inappropriate context reference>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>> 2. Is redundant with the newline designator.
>>>>>>>>>>>
>>>>>>>>>> <snipped inappropriate context reference>
>>>>>>>>>>
>>>>>>>>>>> is obviously false,
>>>>>>>>>>
>>>>>>>>>> If I put it on the list, it wasn't obvious at all, even if it is
>>>>>>>>>> incorrect
>>>>>>>>>> (though I think it is correct).
>>>>>>>>>>
>>>>>>>>>>> unless
>>>>>>>>>>> you specifically require a line continuation character:
>>>>>>>>>>>
>>>>>>>>>>> a = b +
>>>>>>>>>>> c
>>>>>>>>>>
>>>>>>>>>> Without semicolon requirement:
>>>>>>>>>>
>>>>>>>>>> a=b+ // this is an error
>>>>>>>>>> c // this is OK
>>>>>>>>>>
>>>>>>>>>> With semicolon requirement:
>>>>>>>>>>
>>>>>>>>>> a=b+; // this is an error
>>>>>>>>>> c; // this is OK
>>>>>>>>>>
>>>>>>>>>> What's the diff?
>>>>>>>>>>
>>>>>>>>>>> A newline and a semicolon are not redundant unless you
>>>>>>>>>>> specifically
>>>>>>>>>>> define
>>>>>>>>>>> a statement as being one and only one line.
>>>>>>>>>>
>>>>>>>>>> A semicolon is redundate with newline for single-statement lines.
>>>>>>>>>> Oh, you
>>>>>>>>>> say that a lot of constructs are inherently single statements but
>>>>>>>>>> written
>>>>>>>>>> on
>>>>>>>>>> multiple lines? Well, that may be just the kind of examination
>>>>>>>>>> I was
>>>>>>>>>> looking
>>>>>>>>>> for (ironic that _I_ had to bring it up, huh):
>>>>>>>>>>
>>>>>>>>>> if(true)
>>>>>>>>>> dothis()
>>>>>>>>>>
>>>>>>>>>> That situation has to be evaluated: is parsing at the construct
>>>>>>>>>> level too
>>>>>>>>>> much effort or is it desireable? (ParseIfStatement()).
>>>>>>>>>> Statement-level
>>>>>>>>>> parsing better/worse than line-level parsing?
>>>>>>>>>>
>>>>>>>>>>> Back to the magic of above though. What if you rewrote it:
>>>>>>>>>>> a = b
>>>>>>>>>>> +c
>>>>>>>>>>
>>>>>>>>>> Without semicolon requirement:
>>>>>>>>>>
>>>>>>>>>> a=b // OK
>>>>>>>>>> +c // error
>>>>>>>>>>
>>>>>>>>>> With semicolon requirement:
>>>>>>>>>>
>>>>>>>>>> a=b; // OK
>>>>>>>>>> +c; // error
>>>>>>>>>>
>>>>>>>>>> What's the diff?
>>>>>>>>>
>>>>>>>>> a=b
>>>>>>>>> +c(d) // no error
>>>>>>>>
>>>>>>>> Why not?
>>>>>>>
>>>>>>> Good question. Because the compiler accepts a=b;+c(d);.
>>>>>>>
>>>>>>> Whether c is declared as a variable or a function, it still looks
>>>>>>>> wrong to me. A statement can't begin with a +.
>>>>>>>
>>>>>>> OK.
>>>>>>>
>>>>>>> struct S { int a }
>>>>>>> int a
>>>>>>>
>>>>>>> void main () {
>>>>>>> S s
>>>>>>> auto t = s
>>>>>>> .a = 1 // ambiguity: Note that .sth means global scope.
>>>>>>> }
>>>>>>>
>>>>>> That clearly means the global int a is set to one, and the local t 
>>>>>> has
>>>>>> type S.
>>>>>
>>>>> No, s(lots of whitespace).a is a valid expression. You shouldn't
>>>>> insert a statement break there.
>>>>
>>>> But without semicolons the line break becomes the new semicolon. That's
>>>> what most people here don't understand. There's no ambiguity: if you
>>>> have a line break and a semicolon would have been good in that place,
>>>> then that line break becomes the semicolon.
>>>
>>> So
>>>
>>> auto t = s.
>>> a = 1
>>>
>>> would now become a syntax error?
>> Yes. Do you use this particular style of coding often?
> 
> auto s = "No, but you've just broken " ~
>          "some other perfectly working " ~
>          "D codes."
> writeln(s)
Maybe true, but not ambigous.