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D - Property syntax

reply Karl Bochert <kbochert ix.netcom.com> writes:
   class Abc   {
      int myprop;
      void property(int newproperty) { myprop = newproperty; } // set'er
      int property() { return myprop; }// get'er
      }

Isn't this syntax horribly redundant?

Doesn't
 
   class Abc   {
      int <property> myprop;
      }

carry just as much meaning?  The compiler can generate default
gets and sets, and allow user-defined ones as well.

   class Abc  {
       int <property> myprop;
       void myprop ( Error ("Can't set myprop!") );
      }

This provides clarity, saves a lot of typing, and (I would guess) is
easy to implement.

Karl Bochert
May 18 2002
next sibling parent reply "Pavel Minayev" <evilone omen.ru> writes:
"Karl Bochert" <kbochert ix.netcom.com> wrote in message
news:1103_1021740941 bose...

 Doesn't

    class Abc   {
       int <property> myprop;
       }

 carry just as much meaning?  The compiler can generate default
 gets and sets, and allow user-defined ones as well.

No, because it doesn't allow for compile-time read-only (and write-only) properties.
    class Abc  {
        int <property> myprop;
        void myprop ( Error ("Can't set myprop!") );
       }

 This provides clarity, saves a lot of typing, and (I would guess) is
 easy to implement.

Clarity, maybe. But I don't care much of it, personally. As long as one groups property gettors and settors together, they are easy to spot. A lot of typing? Note, you had to define one function to define the property as read-only. Currently, you'd just define a single gettor. The same goes for write-only properties. And if it's read/write, you'll have to define 2 functions + 1 line which declares the property itself...
May 18 2002
parent Karl Bochert <kbochert ix.netcom.com> writes:
On Sat, 18 May 2002 21:07:22 +0400, "Pavel Minayev" <evilone omen.ru> wrote:
 "Karl Bochert" <kbochert ix.netcom.com> wrote in message
 news:1103_1021740941 bose...
 
 Doesn't

    class Abc   {
       int <property> myprop;
       }

 carry just as much meaning?  The compiler can generate default
 gets and sets, and allow user-defined ones as well.

No, because it doesn't allow for compile-time read-only (and write-only) properties.

Surely it is better to have the read-only-ness expressed in the declaration than in the presence or absence of a specific function, somewhere in multiple pages of code!
    class Abc  {
        int <property> myprop;
        void myprop ( Error ("Can't set myprop!") );
       }

 This provides clarity, saves a lot of typing, and (I would guess) is
 easy to implement.

Clarity, maybe. But I don't care much of it, personally. As long as one groups property gettors and settors together, they are easy to spot.

Of course they also move more interesting code to the next page.
 A lot of typing? Note, you had to define one function to define
 the property as read-only. Currently, you'd just define a single
 gettor. The same goes for write-only properties. And if it's
 read/write, you'll have to define 2 functions + 1 line which
 declares the property itself...
 

I was looking at the example give in the manual, where a justification for the current syntax was that it reduced typing (from 111 characters to 99) as compared to C. This syntax reduces the example to 22, at no loss of clarity. Of course the issue is not typing, but the presence of 'typographic noise'. Karl
May 18 2002
prev sibling parent reply "anderson" <anderson firestar.com.au> writes:
Err, hm

Basically what http://www.digitalmars.com/d/class.html is saying is to use

class Abc
{
      int property;
}

Until you need to cater for special cases then put the getters and setters
on, which is one word less then your <property> method.

PS -
It'd be nice though, if a resulting D IDE, could auto generate geter and
seter code (when it was needed) or even better support UML.


"Karl Bochert" <kbochert ix.netcom.com> wrote in message
news:1103_1021740941 bose...
    class Abc   {
       int myprop;
       void property(int newproperty) { myprop = newproperty; } // set'er
       int property() { return myprop; }// get'er
       }

 Isn't this syntax horribly redundant?

 Doesn't

    class Abc   {
       int <property> myprop;
       }

 carry just as much meaning?  The compiler can generate default
 gets and sets, and allow user-defined ones as well.

    class Abc  {
        int <property> myprop;
        void myprop ( Error ("Can't set myprop!") );
       }

 This provides clarity, saves a lot of typing, and (I would guess) is
 easy to implement.

 Karl Bochert

May 18 2002
next sibling parent reply Jonathan Andrew <jon ece.arizona.edu> writes:
So are all instance variables considered public by default then?
-Jon

anderson wrote:

 Err, hm
 
 Basically what http://www.digitalmars.com/d/class.html is saying is to use
 
 class Abc
 {
       int property;
 }
 
 

May 19 2002
parent "anderson" <anderson firestar.com.au> writes:
That'd be my guess to since much of the sample code at
http://www.digitalmars.com is represented that way.  After I had added my
get and set functions I'd move the variable into protected or private space.


"Jonathan Andrew" <jon ece.arizona.edu> wrote in message
news:3CE7E24B.5040209 ece.arizona.edu...
 So are all instance variables considered public by default then?
 -Jon

 anderson wrote:

 Err, hm

 Basically what http://www.digitalmars.com/d/class.html is saying is to


 class Abc
 {
       int property;
 }


May 19 2002
prev sibling parent Erick JA <Erick_member pathlink.com> writes:
In article <ac7h7t$8il$1 digitaldaemon.com>, anderson says...
Err, hm

Basically what http://www.digitalmars.com/d/class.html is saying is to use

 .....



Properties work fine for RAD aproach, make code more clear, an u can make properties read,read/write, public, private...and more. To day language not is only a compiler is more than that, we need tools (builder, RADs, and more). One example, if you wan't make Enterprice JavaBeans you nead emulate properties in the program, in the IDE or Builder and in the interface, so are to bad properties?
May 20 2002