• zwang (9/9) Oct 26 2005 import std.stdio;
• Derek Parnell (10/20) Oct 26 2005 Of course it fails. The 'auto' facility requires a compile-time expressi...
• zwang (2/24) Oct 26 2005 I see no reason why the data type can not be inferred from arrayid.
• Derek Parnell (19/42) Oct 26 2005 I agree. However the 'auto' uses *exactly* the same data type as the
• Ivan Senji (7/58) Oct 27 2005 No sense? But in both these cases the meaning would be the same: infer

zwang <nehzgnaw gmail.com> writes:

import std.stdio;

int main(char[][] args){
	for(auto i=0; i<args.length; ++i) //this works.
		writef(args[i]);
	foreach(auto i; args) //fails to compile
		writef(i);
	
	return 0;
}

Derek Parnell <derek psych.ward> writes:

On Thu, 27 Oct 2005 11:59:11 +0800, zwang wrote:

 import std.stdio;
 
 int main(char[][] args){
 	for(auto i=0; i<args.length; ++i) //this works.
 		writef(args[i]);
 	foreach(auto i; args) //fails to compile
 		writef(i);
 	
 	return 0;
 }

Of course it fails. The 'auto' facility requires a compile-time expression
in order to determine the data type. The syntax for the foreach is 

  'foreach' '(' [('int' | 'uint') ident,] typeid ident ';' arrayid ')' 

There is no place for an 'auto' declaration.

-- 
Derek
(skype: derek.j.parnell)
Melbourne, Australia
27/10/2005 2:56:37 PM

zwang <nehzgnaw gmail.com> writes:

Derek Parnell wrote:
 On Thu, 27 Oct 2005 11:59:11 +0800, zwang wrote:
 
 
import std.stdio;

int main(char[][] args){
	for(auto i=0; i<args.length; ++i) //this works.
		writef(args[i]);
	foreach(auto i; args) //fails to compile
		writef(i);
	
	return 0;
}

 
 
 Of course it fails. The 'auto' facility requires a compile-time expression
 in order to determine the data type. The syntax for the foreach is 
 
   'foreach' '(' [('int' | 'uint') ident,] typeid ident ';' arrayid ')' 
 
 There is no place for an 'auto' declaration.
 

I see no reason why the data type can not be inferred from arrayid.

Derek Parnell <derek psych.ward> writes:

On Thu, 27 Oct 2005 14:37:17 +0800, zwang wrote:

 Derek Parnell wrote:
 On Thu, 27 Oct 2005 11:59:11 +0800, zwang wrote:
 
import std.stdio;

int main(char[][] args){
	for(auto i=0; i<args.length; ++i) //this works.
		writef(args[i]);
	foreach(auto i; args) //fails to compile
		writef(i);
	
	return 0;
}

 
 Of course it fails. The 'auto' facility requires a compile-time expression
 in order to determine the data type. The syntax for the foreach is 
 
   'foreach' '(' [('int' | 'uint') ident,] typeid ident ';' arrayid ')' 
 
 There is no place for an 'auto' declaration.
 

 
 I see no reason why the data type can not be inferred from arrayid.

I agree. However the 'auto' uses *exactly* the same data type as the
expression but foreach needs the element's data type and not the array's
data type. 

But as you suggest, I have yet to see a foreach in which the element data
type is not redundant. We could have had the syntax as  ...

   'foreach' '(' [('int' | 'uint') ident,] ident ';' arrayid ')' 

e.g.  foreach(a; args) 

and that would still make sense to me. But to overload 'auto' with yet
another meaning is starting to appear crazy.

Oh hang on, there is a special case ....

   char[] args;
   foreach( dchar c; args)

where the UTF translation is automated for us.

-- 
Derek
(skype: derek.j.parnell)
Melbourne, Australia
27/10/2005 4:44:11 PM

Ivan Senji <ivan.senji_REMOVE_ _THIS__gmail.com> writes:

Derek Parnell wrote:
 On Thu, 27 Oct 2005 14:37:17 +0800, zwang wrote:
 
 
Derek Parnell wrote:

On Thu, 27 Oct 2005 11:59:11 +0800, zwang wrote:


import std.stdio;

int main(char[][] args){
	for(auto i=0; i<args.length; ++i) //this works.
		writef(args[i]);
	foreach(auto i; args) //fails to compile
		writef(i);
	
	return 0;
}

Of course it fails. The 'auto' facility requires a compile-time expression
in order to determine the data type. The syntax for the foreach is 

  'foreach' '(' [('int' | 'uint') ident,] typeid ident ';' arrayid ')' 

There is no place for an 'auto' declaration.

I see no reason why the data type can not be inferred from arrayid.

 
 
 I agree. However the 'auto' uses *exactly* the same data type as the
 expression but foreach needs the element's data type and not the array's
 data type. 
 
 But as you suggest, I have yet to see a foreach in which the element data
 type is not redundant. We could have had the syntax as  ...
 
    'foreach' '(' [('int' | 'uint') ident,] ident ';' arrayid ')' 
 
 e.g.  foreach(a; args) 
 
 and that would still make sense to me. But to overload 'auto' with yet
 another meaning is starting to appear crazy.
 

No sense? But in both these cases the meaning would be the same: infer 
type from available information. IMO this sytax extension would be quite 
usefull because in foreach you can know the index and array type at 
compile time (except in your special case)

By the way, your definition of foreach syntax is wrong, as the index 
type doesn't need to be int or uint (for example in associative arrays)

 Oh hang on, there is a special case ....
 
    char[] args;
    foreach( dchar c; args)
 
 where the UTF translation is automated for us.