• ketmar (9/9) Mar 27 2014 why foreach() using the current syntax instead of clearer one:
• Dicebot (3/14) Mar 27 2014 You can use `auto` in foreach, as well as any explicit type. It
• ketmar (6/8) Mar 27 2014 no, i can't. at least in current GDC.
• ketmar (10/11) Mar 28 2014 ah grok it. that's cause foreach() is just a syntactic sugar for
• Matej Nanut (6/6) Mar 28 2014 I was sure adding auto would work. I'm still sure it does in some
• ketmar (3/7) Mar 28 2014 parser doesn't accept 'auto' in foreach(). i made a patch for it,
• w0rp (3/11) Mar 28 2014 I reckon that is a bug, and it should be legal. Perhaps someone
• Timon Gehr (3/17) Mar 28 2014 It is documented that code like the above is illegal:
• ketmar (5/6) Mar 28 2014 yes, it is. but i think that 'auto' is a perfect fit there. it
• ketmar (1/2) Mar 28 2014 i mean 'optional auto'.
• w0rp (4/10) Mar 28 2014 Yes, I think this might be a case for a minor thing for allowing

"ketmar" <ketmar ketmar.no-ip.org> writes:

why foreach() using the current syntax instead of clearer one:
foreach (auto v; smth)?

i think that adding 'auto' will make foreach() less confusing, as
it clearly points that 'v' is a local variable for foreach()
scope. and i think that it will be in line with other forms such
as foreach(immutable v; smth), etc.

current foreach() syntax (without auto) still sometimes confusing
me and forcing to believe that i should either put 'auto' inside
foreach() or somehow declare 'v' before foreach().

"Dicebot" <public dicebot.lv> writes:

On Thursday, 27 March 2014 at 09:19:20 UTC, ketmar wrote:
 why foreach() using the current syntax instead of clearer one:
 foreach (auto v; smth)?

 i think that adding 'auto' will make foreach() less confusing, 
 as
 it clearly points that 'v' is a local variable for foreach()
 scope. and i think that it will be in line with other forms such
 as foreach(immutable v; smth), etc.

 current foreach() syntax (without auto) still sometimes 
 confusing
 me and forcing to believe that i should either put 'auto' inside
 foreach() or somehow declare 'v' before foreach().

You can use `auto` in foreach, as well as any explicit type. It 
can be omitted because it is unambiguous.

"ketmar" <ketmar ketmar.no-ip.org> writes:

 You can use `auto` in foreach, as well as any explicit type. It 
 can be omitted because it is unambiguous.

no, i can't. at least in current GDC.

import std.stdio, std.string;

void main () {
     foreach (auto val; [0,1,2,3]) writeln(val);
}

error: basic type expected, not auto

"ketmar" <ketmar ketmar.no-ip.org> writes:

 error: basic type expected, not auto

ah grok it. that's cause foreach() is just a syntactic sugar for 
call with delegate arg, and we can't use 'auto' in arglist.

it's perfectly logical from the point of compiler writer, but 
still forces language user to remember that foreach() is a very 
special beast. i think that just ignoring 'auto' in foreach() 
parser will not harm anyone and will bring 'normal user logic' 
back.

but i'm relatively new to D, so i need some discussion before 
entering request to bugzilla: maybe this is a very old problem 
that was talked to death?

Matej Nanut <matejnanut gmail.com> writes:

I was sure adding auto would work. I'm still sure it does in some
cases, but can't try right now.

I guess it depends on the type of foreach?

If I understand foreach correctly, it uses either opApply() or the
range static interface to do its job, and with a range interface
"auto" does actually work?

"ketmar" <ketmar ketmar.no-ip.org> writes:

 If I understand foreach correctly, it uses either opApply() or 
 the
 range static interface to do its job, and with a range interface
 "auto" does actually work?

parser doesn't accept 'auto' in foreach(). i made a patch for it, 
but not sure if it will be accepted, as there is no good tests 
and no language spec fix.

"w0rp" <devw0rp gmail.com> writes:

On Thursday, 27 March 2014 at 10:30:59 UTC, ketmar wrote:
 You can use `auto` in foreach, as well as any explicit type. 
 It can be omitted because it is unambiguous.

 no, i can't. at least in current GDC.

 import std.stdio, std.string;

 void main () {
     foreach (auto val; [0,1,2,3]) writeln(val);
 }

 error: basic type expected, not auto

I reckon that is a bug, and it should be legal. Perhaps someone 
else will know more.

Timon Gehr <timon.gehr gmx.ch> writes:

On 03/28/2014 01:58 PM, w0rp wrote:
 On Thursday, 27 March 2014 at 10:30:59 UTC, ketmar wrote:
 You can use `auto` in foreach, as well as any explicit type. It can
 be omitted because it is unambiguous.

 no, i can't. at least in current GDC.

 import std.stdio, std.string;

 void main () {
     foreach (auto val; [0,1,2,3]) writeln(val);
 }

 error: basic type expected, not auto

 I reckon that is a bug, and it should be legal. Perhaps someone else
 will know more.

It is documented that code like the above is illegal:

http://dlang.org/statement.html#ForeachType

"ketmar" <ketmar ketmar.no-ip.org> writes:

 It is documented that code like the above is illegal:

yes, it is. but i think that 'auto' is a perfect fit there. it 
shouldn't do anything at all, but it is the convient way to mark 
variable 'locality'. it will not break any of the existing code 
yet will bring foreach() in line with 'every variable must be 
explicitly declared with some type' principle.

"ketmar" <ketmar ketmar.no-ip.org> writes:

 it will not break any of the existing code

i mean 'optional auto'.

"w0rp" <devw0rp gmail.com> writes:

On Friday, 28 March 2014 at 23:29:19 UTC, ketmar wrote:
 It is documented that code like the above is illegal:

 yes, it is. but i think that 'auto' is a perfect fit there. it 
 shouldn't do anything at all, but it is the convient way to 
 mark variable 'locality'. it will not break any of the existing 
 code yet will bring foreach() in line with 'every variable must 
 be explicitly declared with some type' principle.

Yes, I think this might be a case for a minor thing for allowing 
something trivial which, honestly doesn't really matter, but it's 
sort of a "why not?" thing.