Manifest constants (was const again)

[Bill Baxter]

Simen Kjaeraas wrote:
> Bill Baxter wrote:
>>>  Because it breaks with the C/C++ heritage, methinks.
>>
>> I hate to point out the obvious, but there is no "alias" in C or C++.
>> Ok, yes there's typedef in C, but if you go and completely change the 
>> keyword used, I think you are justified in changing the syntax.
> 
> Thank you, I'm well aware of that. My point was typedef. Having typedef 
> and alias (which do /similar/ things) have vastly different syntax would 
> seem strange (and break existing code). Changing both to the 'op dst = 
> src' syntax might have its advantages, though.
> 
>>> Anyways, is there a reason why we can't use 'alias 3.14 pi;'?
>>
>> Things like
>>     alias 3.14 + ctfe_func("two") / other_constant pi;
>>
>> make that much harder to read than
>>
>>     alias pi = 3.14 + ctfe_func("two") / other_constant;
>>
>> But the same is true for the current type aliases.  You can see it a 
>> lot in templates.  There its not uncommon to see things like
>>
>>    alias some long thing that eventually figures out a type Foo;
>>
>> --bb
> 
> I fully agree with that. Yet that is how things are at the moment, and 
> at the very least we should strive to have a consistent syntax, so you 
> don't define constants using 'alias a = 4' and types using 'alias src dst'.

I think it would be a good candidate for preservation of C-ish syntax as 
an aid to porting and C refugees.

Just like in D we have float[] x  as the improved syntax and float x[] 
as legacy syntax, we could have both  "alias Y=X" as new-and-improved 
and "alias X Y" as an aid to porting.  As for being confusing, doing it 
the wrong way is going to be a compiler error, so I don't think it's a 
big deal.

 > Also, like some people like to point out (me often coding in notepad
 > excludes me from that group), a good IDE might make it more obvious.

I think code should be as readable as possible without an IDE.  If 
you're going to design a language with the use of IDEs in mind then go 
all the way and make it integral, like with Smalltalk.

--bb