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reply spir <denis.spir gmail.com> writes:
Hello,

Is the D way to make read-only symbols (of a class, struct, module) to writ=
e a getter for a private symbols?

Additional question: just realised one can omit () on func calls! Is this s=
ystematic when a func has no param? I thought it was not the case, because =
it does not work with writeln (the first func on which I tried, indeed!). I=
s it only because writeln is parameterized (with (T...)) or is there any ot=
her reason I'm not aware of?

struct P {
    private int my_i;
    int i() {return this.my_i;}
    void doit() {writeln("...doing...");}
}
void main () {
    auto p =3D P(1);
    writeln("p.i: ",p.i);
    p.doit;
}


Denis
-- -- -- -- -- -- --
vit esse estrany =E2=98=A3

spir.wikidot.com
Nov 02 2010
parent reply Jesse Phillips <jessekphillips+D gmail.com> writes:
spir Wrote:


 Hello,
 
 Is the D way to make read-only symbols (of a class, struct, module) to write a
getter for a private symbols?


Yes, though it isn't like the getValue() from java.

 property  int i() {return this.my_i;}


 Additional question: just realised one can omit () on func calls! Is this
systematic when a func has no param? I thought it was not the case, because it
does not work with writeln (the first func on which I tried, indeed!). Is it
only because writeln is parameterized (with (T...)) or is there any other
reason I'm not aware of?


Calling functions without () is a legacy feature left over which is how D use
to do properties. Some will say this is going to be removed, but do not recall
this ever being said (only that it was implied it would happen if properties
were used).

Personally if it doesn't go away I see no reason to have  property, as the only
reason I thought it was a good idea was for when you were taking the address of
a function who returns a function (makes it a little hard to read). Otherwise I
like the omit-able ().

writeln is a template, so I suppose you can't call it this way since it can't
instantiate an instance until it knows what parameters are past. You probably
could call it like this writeln!() but that kind of defeats the idea of leaving
off the ().
Nov 02 2010
parent reply "Steven Schveighoffer" <schveiguy yahoo.com> writes:
On Tue, 02 Nov 2010 15:54:13 -0400, Jesse Phillips  
<jessekphillips+D gmail.com> wrote:


 Calling functions without () is a legacy feature left over which is how  
 D use to do properties. Some will say this is going to be removed, but  
 do not recall this ever being said (only that it was implied it would  
 happen if properties were used).


TDPL states it will be required.

-Steve
Nov 02 2010
parent reply Jesse Phillips <jessekphillips+D gmail.com> writes:
Steven Schveighoffer Wrote:


 On Tue, 02 Nov 2010 15:54:13 -0400, Jesse Phillips  
 <jessekphillips+D gmail.com> wrote:
 

 Calling functions without () is a legacy feature left over which is how  
 D use to do properties. Some will say this is going to be removed, but  
 do not recall this ever being said (only that it was implied it would  
 happen if properties were used).


 
 TDPL states it will be required.
 
 -Steve


I do not believe it does. I don't recall seeing it, nor do I think it makes any
sense to even mention it considering it shouldn't mention bugs in the
implementation. That said, I don't recall it mentioning functions being
callable without parens.
Nov 02 2010
parent reply "Steven Schveighoffer" <schveiguy yahoo.com> writes:
On Tue, 02 Nov 2010 16:52:38 -0400, Jesse Phillips  
<jessekphillips+D gmail.com> wrote:


 Steven Schveighoffer Wrote:


 On Tue, 02 Nov 2010 15:54:13 -0400, Jesse Phillips
 <jessekphillips+D gmail.com> wrote:


 Calling functions without () is a legacy feature left over which is  


 how

 D use to do properties. Some will say this is going to be removed, but
 do not recall this ever being said (only that it was implied it would
 happen if properties were used).


 TDPL states it will be required.

 -Steve


 I do not believe it does. I don't recall seeing it, nor do I think it  
 makes any sense to even mention it considering it shouldn't mention bugs  
 in the implementation. That said, I don't recall it mentioning functions  
 being callable without parens.


It does not say that functions should be callable without parentheses,  
because that mis-feature is deprecated.  Essentially, to someone who is  
new to D, there is no need to mention the historical features of D.  It  
does say that you need to put  property on functions to make them into  
properties.  At least the copy I reviewed said that (I don't have a final  
copy).

-Steve
Nov 02 2010
parent reply Jesse Phillips <jessekphillips+D gmail.com> writes:
Steven Schveighoffer Wrote:


 It does not say that functions should be callable without parentheses,  
 because that mis-feature is deprecated.  Essentially, to someone who is  
 new to D, there is no need to mention the historical features of D.  It  
 does say that you need to put  property on functions to make them into  
 properties.  At least the copy I reviewed said that (I don't have a final  
 copy).
 
 -Steve


I think part of my distrust is I recall getting an error message to the effect
of:

Error: cannot call property function using ()

But I'm not getting any such error now, so I don't know what I was fixing.
Nov 02 2010
next sibling parent Jonathan M Davis <jmdavisProg gmx.com> writes:
On Tuesday 02 November 2010 15:02:04 Jesse Phillips wrote:

 Steven Schveighoffer Wrote:

 It does not say that functions should be callable without parentheses,
 because that mis-feature is deprecated.  Essentially, to someone who is
 new to D, there is no need to mention the historical features of D.  It
 does say that you need to put  property on functions to make them into
 properties.  At least the copy I reviewed said that (I don't have a final
 copy).
 
 -Steve


 
 I think part of my distrust is I recall getting an error message to the
 effect of:
 
 Error: cannot call property function using ()
 
 But I'm not getting any such error now, so I don't know what I was fixing.


Properties are discussed on page 156 of TDPL. It specifically states that 
property functions _must_ be called without parentheses but says nothing about 
whether you can call other functions without them - presumably because it's 
assumed that the way to call a function is with parens and that being able to 
call non-property functions without parens is not supposed to be in the
language 
anymore, so there's no point in mentioning it.

- Jonathan M Davis
Nov 02 2010
prev sibling parent "Steven Schveighoffer" <schveiguy yahoo.com> writes:
On Tue, 02 Nov 2010 18:02:04 -0400, Jesse Phillips  
<jessekphillips+D gmail.com> wrote:


 Steven Schveighoffer Wrote:


 It does not say that functions should be callable without parentheses,
 because that mis-feature is deprecated.  Essentially, to someone who is
 new to D, there is no need to mention the historical features of D.  It
 does say that you need to put  property on functions to make them into
 properties.  At least the copy I reviewed said that (I don't have a  
 final
 copy).

 -Steve


 I think part of my distrust is I recall getting an error message to the  
 effect of:

 Error: cannot call property function using ()

 But I'm not getting any such error now, so I don't know what I was  
 fixing.


IIRC, the compiler has some enforcement but not complete enforcement.

I would not trust the compiler.  The intent is for omission of parentheses  
to be required for, and valid only for  property functions.

-Steve
Nov 03 2010