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digitalmars.D.learn - property usage

reply "uri" <uri.grill gmail.com> writes:
Hi All,

Do you guys use  property much, or is it largely ignored/avoided?

Thanks,
uri
Dec 04 2014
next sibling parent reply Rikki Cattermole <alphaglosined gmail.com> writes:
On 4/12/2014 11:21 p.m., uri wrote:

 Hi All,

 Do you guys use  property much, or is it largely ignored/avoided?

 Thanks,
 uri


When it makes sense I use it.

https://github.com/Devisualization/window/blob/master/interfaces/devisualization/window/interfaces/window.d#L144

vs

https://github.com/rikkimax/Dobol/blob/master/source/dobol/parser/dobol/parser/defs.d
Dec 04 2014
parent "uri" <uri.grill gmail.com> writes:
On Thursday, 4 December 2014 at 10:24:00 UTC, Rikki Cattermole 
wrote:

 On 4/12/2014 11:21 p.m., uri wrote:

 Hi All,

 Do you guys use  property much, or is it largely 
 ignored/avoided?

 Thanks,
 uri


 When it makes sense I use it.

 https://github.com/Devisualization/window/blob/master/interfaces/devisualization/window/interfaces/window.d#L144

 vs

 https://github.com/rikkimax/Dobol/blob/master/source/dobol/parser/dobol/parser/defs.d


Thanks for the examples. As always I found what I needed just 
after posting:

http://wiki.dlang.org/Property_Discussion_Wrap-up


/uri
Dec 04 2014
prev sibling next sibling parent ketmar via Digitalmars-d-learn <digitalmars-d-learn puremagic.com> writes:
On Thu, 04 Dec 2014 10:21:10 +0000
uri via Digitalmars-d-learn <digitalmars-d-learn puremagic.com> wrote:


 Do you guys use  property much, or is it largely ignored/avoided?


i'm using it alot for the things that looks like properties. ;-)

the thing is looking like a property if it works almost as fast as
accesing the field directly. i.e. does simple check or two, but doesn't
calculate something heavy. that means that `area` for Rect is
definitely a property, but `equalElementCount` for a single-linked list
is not.

i also using that alot to simulate read-only fields.
Dec 04 2014
prev sibling next sibling parent Jonathan M Davis via Digitalmars-d-learn writes:
On Thursday, December 04, 2014 10:21:10 uri via Digitalmars-d-learn wrote:

 Hi All,

 Do you guys use  property much, or is it largely ignored/avoided?


 property is used rather freuently - e.g. some of the functions in the range
API are required to be properties. Typically,  property is used when you'd
use a getter or setter in another language (or when you need to emulate a
variable). Using get* or set* would generally not be considered idiomatic D
and is not typically done.  property functions are used instead.

Now, because the parens are optional on functions with no arguments, there
are plenty of cases where functions are called without parens when they're
not properties, but property functions are quite common.

- Jonathan M Davis
Dec 06 2014
prev sibling parent reply ketmar via Digitalmars-d-learn <digitalmars-d-learn puremagic.com> writes:
On Sat, 06 Dec 2014 15:23:10 -0800
Jonathan M Davis via Digitalmars-d-learn
<digitalmars-d-learn puremagic.com> wrote:


 On Thursday, December 04, 2014 10:21:10 uri via Digitalmars-d-learn wrote:

 Hi All,

 Do you guys use  property much, or is it largely ignored/avoided?


=20
  property is used rather freuently - e.g. some of the functions in the ra=


nge

 API are required to be properties. Typically,  property is used when you'd
 use a getter or setter in another language (or when you need to emulate a
 variable). Using get* or set* would generally not be considered idiomatic=


 D

 and is not typically done.  property functions are used instead.
=20
 Now, because the parens are optional on functions with no arguments, there
 are plenty of cases where functions are called without parens when they're
 not properties, but property functions are quite common.


we all waiting for property enforcement fixes (which i already
integrated, heh), so delegate properties can be used as propeties,
omiting the annoying '()'.

as this can break some invalid code (the code where people using
properties as functions) i assume that we'll live with half-backed
properties forever.
Dec 06 2014
parent reply "Nicholas Londey" <londey gmail.com> writes:
 as this can break some invalid code (the code where people using
 properties as functions)


Does  property ever make sense for a free floating function? I 
would have thought no but was recently asked to add it if using 
the function with uniform call syntax.

https://github.com/D-Programming-Language/dub/pull/455#discussion_r21430311
Dec 08 2014
next sibling parent ketmar via Digitalmars-d-learn <digitalmars-d-learn puremagic.com> writes:
On Tue, 09 Dec 2014 07:31:20 +0000
Nicholas Londey via Digitalmars-d-learn
<digitalmars-d-learn puremagic.com> wrote:


 as this can break some invalid code (the code where people using
 properties as functions)


=20
 Does  property ever make sense for a free floating function? I=20
 would have thought no but was recently asked to add it if using=20
 the function with uniform call syntax.
=20
 https://github.com/D-Programming-Language/dub/pull/455#discussion_r214303=


11
when you want to make a function that acts as getter/setter for
delegate callback, for example.

  private void delegate () cb;
   property auto myCB () { return cb; }
   property void myCB (void delegate () newcb) {
    /* some checks */
    cb =3D newcb;
  }

this will work as expected when property enforcement will be fixed --
i.e. you will be able to omit '()' for calling delegate.

alas, this is another thing that is "cosmetic", so PR with property
enforcement will rot on github forever.
Dec 08 2014
prev sibling next sibling parent Mike Parker <aldacron gmail.com> writes:
On 12/9/2014 4:31 PM, Nicholas Londey wrote:


 Does  property ever make sense for a free floating function? I would
 have thought no but was recently asked to add it if using the function
 with uniform call syntax.


I use it from time-to-time. I assume you think of properties as 
belonging to objects and not just something that is useful with UFCS. 
Keep in mind that free-floating functions belong to modules and modules 
(usually) belong to packages. These are units of encapsulation above 
classes & structs. There could be (and has been in these forums) lengthy 
debate about what constitutes a property and what doesn't, but whether 
or not a function belongs to a class or struct shouldn't enter into it, IMO.
Dec 08 2014
prev sibling next sibling parent "uri" <uri.grill gmail.com> writes:
On Tuesday, 9 December 2014 at 07:31:21 UTC, Nicholas Londey 
wrote:

 as this can break some invalid code (the code where people 
 using
 properties as functions)


 Does  property ever make sense for a free floating function? I 
 would have thought no but was recently asked to add it if using 
 the function with uniform call syntax.

 https://github.com/D-Programming-Language/dub/pull/455#discussion_r21430311


After a quick grep I see phobos uses quite a few free floating 
 property...
Dec 09 2014
prev sibling parent Joseph Rushton Wakeling via Digitalmars-d-learn writes:
On 09/12/14 08:31, Nicholas Londey via Digitalmars-d-learn wrote:

 Does  property ever make sense for a free floating function?
Dec 10 2014