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digitalmars.D - Alternative template instantiation syntax

reply =?utf-8?Q?Simen_Kj=C3=A6r=C3=A5s?= <simen.kjaras gmail.com> writes:
A pattern in D is this:

alias Foo!q{
     stuffs
} MyFoo;

Where Foo is a templated struct/class. In many ways, this is similar to
defining a new type, and I therefore throw out the suggestion that the
syntax should reflect this. I may be wrong, but I think this syntax is
unused and fitting:

Foo MyFoo!q{
     stuffs
}

This is clearly symmetrical with the definition of normal types:

class MyClass {
}

struct MyStruct {
}

enum MyEnum {
}

Critique? Thoughts?
Jan 26 2012
next sibling parent "Peter Alexander" <peter.alexander.au gmail.com> writes:
On Friday, 27 January 2012 at 01:24:54 UTC, Simen Kjærås wrote:
 Critique? Thoughts?

What problem does this solve?
Jan 27 2012
prev sibling parent reply Timon Gehr <timon.gehr gmx.ch> writes:
On 01/27/2012 02:24 AM, Simen Kjærås wrote:
 A pattern in D is this:

 alias Foo!q{
 stuffs
 } MyFoo;

 Where Foo is a templated struct/class. In many ways, this is similar to
 defining a new type, and I therefore throw out the suggestion that the
 syntax should reflect this. I may be wrong, but I think this syntax is
 unused and fitting:

 Foo MyFoo!q{
 stuffs
 }

 This is clearly symmetrical with the definition of normal types:

 class MyClass {
 }

 struct MyStruct {
 }

 enum MyEnum {
 }

 Critique? Thoughts?

It looks like Yoda speak to me. I don't think it is going to fly. If we get alias name = othername; as has been suggested a few times, your example would look like: alias MyFoo = Foo!q{ } Is that good enough?
Jan 27 2012
next sibling parent reply "F i L" <witte2008 gmail.com> writes:
Timon Gehr wrote:
 alias MyFoo = Foo!q{

 }

This syntax makes a lot of sense, but why have the '=' at all? Why not just: alias Num float; alias MyFoo Foo!q{ };
Jan 27 2012
parent Timon Gehr <timon.gehr gmx.ch> writes:
On 01/27/2012 11:29 PM, F i L wrote:
 On Friday, 27 January 2012 at 22:20:47 UTC, a wrote:
 On Friday, 27 January 2012 at 22:02:55 UTC, F i L wrote:
 Timon Gehr wrote:
 alias MyFoo = Foo!q{

 }

This syntax makes a lot of sense, but why have the '=' at all? Why not just: alias Num float; alias MyFoo Foo!q{ };



Because then we have alias symbol1 symbol2; which means symbol2 is an alias for symbol1 and alias symbol1 symbol2!(...) which means symbol1 is an alias for symbol2!(...). It does not seem right.
 I guess one reason is that it fits better with the rest of the
 language, it feels more natural. Also, wouldn't your proposal require
 making the current syntax illegal and breaking pretty much all of
 existing D code?

Every proposal here would break D, so I'm not sure what you mean by "my" proposal. Also, because aliases are non-lvalue definitions, I don't think '=' makes a lot of sense, but I'm not an expert on the matter.

No, they are all additive and backwards-compatible changes. (the old syntax would persist as an alternative) And in D the lhs of a = initializer is not required to be an lvalue anyway: enum x = 1;
Jan 27 2012
prev sibling next sibling parent "a" <a a.com> writes:
On Friday, 27 January 2012 at 22:02:55 UTC, F i L wrote:
 Timon Gehr wrote:
 alias MyFoo = Foo!q{

 }

This syntax makes a lot of sense, but why have the '=' at all? Why not just: alias Num float; alias MyFoo Foo!q{ };

I guess one reason is that it fits better with the rest of the language, it feels more natural. Also, wouldn't your proposal require making the current syntax illegal and breaking pretty much all of existing D code?
Jan 27 2012
prev sibling next sibling parent "F i L" <witte2008 gmail.com> writes:
On Friday, 27 January 2012 at 22:20:47 UTC, a wrote:
 On Friday, 27 January 2012 at 22:02:55 UTC, F i L wrote:
 Timon Gehr wrote:
 alias MyFoo = Foo!q{

 }

This syntax makes a lot of sense, but why have the '=' at all? Why not just: alias Num float; alias MyFoo Foo!q{ };

I guess one reason is that it fits better with the rest of the language, it feels more natural. Also, wouldn't your proposal require making the current syntax illegal and breaking pretty much all of existing D code?

Every proposal here would break D, so I'm not sure what you mean by "my" proposal. Also, because aliases are non-lvalue definitions, I don't think '=' makes a lot of sense, but I'm not an expert on the matter.
Jan 27 2012
prev sibling parent "F i L" <witte2008 gmail.com> writes:
 No, they are all additive and backwards-compatible changes.

Ahh I see now, that makes sense.
Jan 27 2012