• "Peter Alexander" <peter.alexander.au gmail.com> Jan 13 2013
• Timon Gehr <timon.gehr gmx.ch> Jan 13 2013
• Timon Gehr <timon.gehr gmx.ch> Jan 13 2013
• Philippe Sigaud <philippe.sigaud gmail.com> Jan 13 2013

"Peter Alexander" <peter.alexander.au gmail.com> writes:

Is there any reason why this isn't allowed:

alias f = (x => x);

but this is:

template A(alias B) { alias A = B; }
alias f = A!(x => x);

???

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

On 01/13/2013 08:55 PM, Peter Alexander wrote:
 Is there any reason why this isn't allowed:

 alias f = (x => x);

 but this is:

 template A(alias B) { alias A = B; }
 alias f = A!(x => x);

 ???


No. It is a gratuitous grammar limitation.

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

On 01/13/2013 09:38 PM, Philippe Sigaud wrote:
 On Sun, Jan 13, 2013 at 9:07 PM, Timon Gehr <timon.gehr gmx.ch> wrote:
 On 01/13/2013 08:55 PM, Peter Alexander wrote:
 Is there any reason why this isn't allowed:

 alias f = (x => x);

 but this is:

 template A(alias B) { alias A = B; }
 alias f = A!(x => x);

 ???



 No. It is a gratuitous grammar limitation.


 The same limitation forbids:

 alias __traits(whatever, ...) result;

 The grammar says:

 AliasDeclaration:
      alias BasicType Declarator

 (and others, but this is the one limiting you). BasicType should be
 replaced by PrimaryExrpession, or something like that.


I think it should be roughly:

alias TemplateArgument Identifier;
alias Identifier=TemplateArgument;


Note: The current grammar allows

alias int x = 2;

Which does not make any sense.

Philippe Sigaud <philippe.sigaud gmail.com> writes:

On Sun, Jan 13, 2013 at 9:07 PM, Timon Gehr <timon.gehr gmx.ch> wrote:
 On 01/13/2013 08:55 PM, Peter Alexander wrote:
 Is there any reason why this isn't allowed:

 alias f = (x => x);

 but this is:

 template A(alias B) { alias A = B; }
 alias f = A!(x => x);

 ???



 No. It is a gratuitous grammar limitation.


The same limitation forbids:

alias __traits(whatever, ...) result;

The grammar says:

AliasDeclaration:
    alias BasicType Declarator

(and others, but this is the one limiting you). BasicType should be
replaced by PrimaryExrpession, or something like that.