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digitalmars.D - $ for length?

reply "Steve Teale" <steve.teale britseyeview.com> writes:
How difficult would it be to allow the '$' to be used instead of
length in something like:

Thing[] ta;
for (size_t i = 0; i < ta.$; i++)

It can be used in slices, and indexes, so it might well be
unambiguous here.
Feb 20 2014
next sibling parent "bearophile" <bearophileHUGS lycos.com> writes:
Steve Teale:


 How difficult would it be to allow the '$' to be used instead of
 length in something like:

 Thing[] ta;
 for (size_t i = 0; i < ta.$; i++)

 It can be used in slices, and indexes, so it might well be
 unambiguous here.


You can vote it:
https://d.puremagic.com/issues/show_bug.cgi?id=7840

Bye,
bearophile
Feb 20 2014
prev sibling next sibling parent reply "w0rp" <devw0rp gmail.com> writes:
On Thursday, 20 February 2014 at 10:28:43 UTC, Steve Teale wrote:

 How difficult would it be to allow the '$' to be used instead of
 length in something like:

 Thing[] ta;
 for (size_t i = 0; i < ta.$; i++)

 It can be used in slices, and indexes, so it might well be
 unambiguous here.


I don't like it. It's a small difference in the number of 
characters between the two on a line, and .length is much easier 
to read, especially for people new to the language. I think given 
D's smaller userbase, anything which makes a line of code easier 
to read for people coming from other languages without getting in 
the way of other things is a bonus.
Feb 20 2014
next sibling parent reply "Chris" <wendlec tcd.ie> writes:
On Thursday, 20 February 2014 at 13:17:37 UTC, w0rp wrote:

 On Thursday, 20 February 2014 at 10:28:43 UTC, Steve Teale 
 wrote:

 How difficult would it be to allow the '$' to be used instead 
 of
 length in something like:

 Thing[] ta;
 for (size_t i = 0; i < ta.$; i++)

 It can be used in slices, and indexes, so it might well be
 unambiguous here.


 I don't like it. It's a small difference in the number of 
 characters between the two on a line, and .length is much 
 easier to read, especially for people new to the language. I 
 think given D's smaller userbase, anything which makes a line 
 of code easier to read for people coming from other languages 
 without getting in the way of other things is a bonus.


Why not have both?
Feb 20 2014
parent "Steve Teale" <steve.teale britseyeview.com> writes:
On Thursday, 20 February 2014 at 13:52:20 UTC, Chris wrote:


 Why not have both?


I was not suggesting otherwise.
Feb 20 2014
prev sibling next sibling parent "bearophile" <bearophileHUGS lycos.com> writes:
w0rp:


 length is much easier to read, especially for people new to the 
 language.


But such new people find code like:  a[$ - 1]  so they need to 
know the meaning of $.

Bye,
bearophile
Feb 20 2014
prev sibling parent reply "Mengu" <mengukagan gmail.com> writes:
On Thursday, 20 February 2014 at 13:17:37 UTC, w0rp wrote:

 On Thursday, 20 February 2014 at 10:28:43 UTC, Steve Teale 
 wrote:

 How difficult would it be to allow the '$' to be used instead 
 of
 length in something like:

 Thing[] ta;
 for (size_t i = 0; i < ta.$; i++)

 It can be used in slices, and indexes, so it might well be
 unambiguous here.


 I don't like it. It's a small difference in the number of 
 characters between the two on a line, and .length is much 
 easier to read, especially for people new to the language. I 
 think given D's smaller userbase, anything which makes a line 
 of code easier to read for people coming from other languages 
 without getting in the way of other things is a bonus.


well, at least it's not len(ta).
Feb 20 2014
parent "bearophile" <bearophileHUGS lycos.com> writes:
Mengu:


 well, at least it's not len(ta).


A free function len() is quite useful if you want to use it in 
higher order functions:

map(len, ["red", "yo"])

In D:

["red", "yo"].map!(s => s.length)
["red", "yo"].map!walkLength

Bye,
bearophile
Feb 20 2014
prev sibling next sibling parent reply "Frustrated" <c1514843 drdrb.com> writes:
On Thursday, 20 February 2014 at 10:28:43 UTC, Steve Teale wrote:

 How difficult would it be to allow the '$' to be used instead of
 length in something like:

 Thing[] ta;
 for (size_t i = 0; i < ta.$; i++)

 It can be used in slices, and indexes, so it might well be
 unambiguous here.


it's ugly, how about ta.opLength = $ta = ta.length?
Feb 20 2014
parent reply "Kagamin" <spam here.lot> writes:
On Thursday, 20 February 2014 at 18:35:26 UTC, Frustrated wrote:

 it's ugly, how about ta.opLength = $ta = ta.length?


Or #ta - what miniD does. See 
http://d.puremagic.com/issues/show_bug.cgi?id=2660
Feb 20 2014
parent "Jesse Phillips" <Jesse.K.Phillips+D gmail.com> writes:
On Thursday, 20 February 2014 at 18:45:49 UTC, Kagamin wrote:

 On Thursday, 20 February 2014 at 18:35:26 UTC, Frustrated wrote:

 it's ugly, how about ta.opLength = $ta = ta.length?


 Or #ta - what miniD does. See 
 http://d.puremagic.com/issues/show_bug.cgi?id=2660


Comes from Lua. It may or may not represent the number of 
elements in a table, since we don't want to correlate to those 
semantics it is probably best to stay away from it.
Feb 20 2014
prev sibling next sibling parent reply "Kagamin" <spam here.lot> writes:
On Thursday, 20 February 2014 at 10:28:43 UTC, Steve Teale wrote:

 How difficult would it be to allow the '$' to be used instead of
 length in something like:

 Thing[] ta;
 for (size_t i = 0; i < ta.$; i++)

 It can be used in slices, and indexes, so it might well be
 unambiguous here.


Early versions of D already had the feature: you could write 
arr[0..length], but the feature proved to be ambiguous and was 
removed.
$ is meant to be a special indexing syntax (like two dots), it's 
not a member, not a length.
Feb 20 2014
parent reply "Stanislav Blinov" <stanislav.blinov gmail.com> writes:
On Thursday, 20 February 2014 at 18:39:43 UTC, Kagamin wrote:


 $ is meant to be a special indexing syntax (like two dots), 
 it's not a member, not a length.


Errr, what? http://dlang.org/operatoroverloading.html#Dollar
Feb 20 2014
parent "Kagamin" <spam here.lot> writes:
On Thursday, 20 February 2014 at 18:43:29 UTC, Stanislav Blinov
wrote:

 On Thursday, 20 February 2014 at 18:39:43 UTC, Kagamin wrote:


 $ is meant to be a special indexing syntax (like two dots), 
 it's not a member, not a length.


 Errr, what? http://dlang.org/operatoroverloading.html#Dollar


It repeats what I said:

 Within the arguments to array index and slicing operators


Well, you can't write a.+(b) - that's a difference between syntax
and member.
Feb 20 2014
prev sibling parent "Jesse Phillips" <Jesse.K.Phillips+D gmail.com> writes:
On Thursday, 20 February 2014 at 10:28:43 UTC, Steve Teale wrote:

 How difficult would it be to allow the '$' to be used instead of
 length in something like:

 Thing[] ta;
 for (size_t i = 0; i < ta.$; i++)

 It can be used in slices, and indexes, so it might well be
 unambiguous here.


My first reaction is disgust, second is I'd probably get use to 
it, third is wondering if I would actually use it given the 
option (probably not).
Feb 20 2014