alternative aliases [Re: [fpc-devel] Re: [fpc-pascal] Re: Ideas for namespace implementation]

[Martin]

On 27/07/2010 10:20, Alexander Klenin wrote:
> On Tue, Jul 27, 2010 at 02:27, Martin<fpc at mfriebe.de>  wrote:
>    
>> uses Foo in 'lcl' alias 'FooLCL', Foo in 'RTL' alias 'FooRTL'
>>      
> I think this is a reasonable idea, with the following caveats:
>
> 1) I think both aliases and namespaces should be identifiers, not strings
> (i.e. quotes are unnecessary distraction).
>    
ok, by me

especially for the namespace (see the wiki page too), it solves the 
difference between

uses Foo in 'LCL'; // a folder called lcl, in the project
uses Foo in LCL; // the namespace

alias without quotes is sensible too.


> 2) I think that namespace-like syntax is preferable, i.e.
> "LCL.Foo", not "Foo in LCL"., additionally, I do think it would do no harm
> to let programmer use "namespaced" unit without alias.
>    
yes and no:
a) "in" is already established
b) ok, but this must only be allowed in the uses clause.
  In the uses clause the dot as no ambiguity . In the source it can have 
(see many earlier mails)
  In the source, the unit should only be known by either it's name, or 
if aliased by it's alias only.

Both alternatives could be allowed, they do not conflict.
Unless in $Mode Delphi, the dot will at some time be used in delphi 
compatibility....

> 3) Finally, after a slight variation of syntax to avoid extra 'alias' keyword,
> we arrive at the following proposed syntax:
>
> uses
>    FooLCL=LCL.Foo, RTL.Foo;
>    
possible => but not my favourite

rather shorten "qalias" to "as"
uses LCL.Foo as LCLFoo


> begin
>     FooLCL.proc();
>    
yes
>     RTL.Foo.proc();
>    
no,no,no
The beauty of the alias is, that the pascal source remains pascal, and 
not a new form of java or C

also RTL.Foo.proc is ambigious.

there could be a
   unit RTL;
   type Foo=class
     class procedure proc;
   end;

> end.
>
> which is quite similar to already existing 'alias' feature for types:
>
> type
>    TFooLCL=LCLUnit.TFoo;
>
> begin
>     TFooLCL.Create();
>     RTLUnit.TFoo.Create();
>    
yes, but if you do the above uniot namespace with dot in source, you 
could also read this as
    unit TFoo, procedure Create(); // in namespace RTLUnit
---
uses RTLUnit.TFoo; RTLUnit.TFoo.Create();