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digitalmars.D.learn - Privatize a few members to allow messing with them #11353

reply matheus <matheus gmail.com> writes:
Hi, I was looking the PR in DMD and I found this one: 
https://github.com/dlang/dmd/pull/11353/

One of the changes was:

-            loc.linnum += incrementLoc;
+            loc.linnum = loc.linnum + incrementLoc;

I usually do the former and I particularly hate the later, so my 
question is, in this case this was more a style thing than 
anything else right? Or is there something I'm not able to see?

Thanks,

Matheus.
Jun 30 2020
parent reply Stanislav Blinov <stanislav.blinov gmail.com> writes:
On Tuesday, 30 June 2020 at 19:42:57 UTC, matheus wrote:


 in this case this was more a style thing than anything else 
 right? Or is there something I'm not able to see?


Before the change, linnum and charnum are public variables, one 
can do a += on them. After the change, they become properties 
accessing, as the PR says, private variables:

      safe  nogc pure  property
     {
         const uint linnum() { return _linnum; }
         const uint charnum() { return _charnum; }
         void linnum(uint rhs) { _linnum = rhs; }
         void charnum(uint rhs) { _charnum = rhs; }
     }

...with which the += won't work (at least this variant, as the 
getter isn't returning ref).
Jun 30 2020
parent reply matheus <matheus gmail.com> writes:
On Tuesday, 30 June 2020 at 19:46:35 UTC, Stanislav Blinov wrote:

 On Tuesday, 30 June 2020 at 19:42:57 UTC, matheus wrote:


 in this case this was more a style thing than anything else 
 right? Or is there something I'm not able to see?


 Before the change, linnum and charnum are public variables, one 
 can do a += on them. After the change, they become properties 
 accessing, as the PR says, private variables:

      safe  nogc pure  property
     {
         const uint linnum() { return _linnum; }
         const uint charnum() { return _charnum; }
         void linnum(uint rhs) { _linnum = rhs; }
         void charnum(uint rhs) { _charnum = rhs; }
     }

 ...with which the += won't work (at least this variant, as the 
 getter isn't returning ref).


Oh I see now and thanks for the information.

Matheus.
Jun 30 2020
parent reply matheus <matheus gmail.com> writes:
On Tuesday, 30 June 2020 at 19:55:56 UTC, matheus wrote:

 On Tuesday, 30 June 2020 at 19:46:35 UTC, Stanislav Blinov

 ...
      safe  nogc pure  property
     {
         const uint linnum() { return _linnum; }
         const uint charnum() { return _charnum; }
         void linnum(uint rhs) { _linnum = rhs; }
         void charnum(uint rhs) { _charnum = rhs; }
     }

 ...with which the += won't work (at least this variant, as the 
 getter isn't returning ref).


 Oh I see now and thanks for the information.


By the way:

+            loc.linnum = loc.linnum + incrementLoc;

This works because it was declared:

void linnum(uint rhs) { _linnum = rhs; }

Right?

Matheus.
Jun 30 2020
parent reply Stanislav Blinov <stanislav.blinov gmail.com> writes:
On Tuesday, 30 June 2020 at 19:58:05 UTC, matheus wrote:


 +            loc.linnum = loc.linnum + incrementLoc;

 This works because it was declared:

 void linnum(uint rhs) { _linnum = rhs; }

 Right?


Almost. Given these definitions:

 safe  nogc pure  property
{
     const uint linnum() { return _linnum; }
     void linnum(uint rhs) { _linnum = rhs; }
}

This:

loc.linnum = loc.linnum + incrementLoc;

is rewritten as:

loc.linnum(loc.linnum() + incrementLoc);
Jun 30 2020
parent matheus <matheus gmail.com> writes:
On Tuesday, 30 June 2020 at 20:01:43 UTC, Stanislav Blinov wrote:

 On Tuesday, 30 June 2020 at 19:58:05 UTC, matheus wrote:


 +            loc.linnum = loc.linnum + incrementLoc;

 This works because it was declared:

 void linnum(uint rhs) { _linnum = rhs; }

 Right?


 Almost. Given these definitions:

  safe  nogc pure  property
 {
     const uint linnum() { return _linnum; }
     void linnum(uint rhs) { _linnum = rhs; }
 }

 This:

 loc.linnum = loc.linnum + incrementLoc;

 is rewritten as:

 loc.linnum(loc.linnum() + incrementLoc);


Alright and thanks again.

Matheus.
Jun 30 2020