• Jean-Louis Leroy (19/19) Feb 21 2018 Here's what I am trying to do:
• Meta (24/43) Feb 21 2018 Mixins have to be full declarations. You can't mix in bits and
• Adam D. Ruppe (4/6) Feb 21 2018 They need to be full declarations, full statements, or full
• Basile B. (6/8) Feb 21 2018 Yes it does, example

Jean-Louis Leroy <jl leroy.nyc> writes:

Here's what I am trying to do:

mixin template MakeFun(string ID, int X)
{
   int mixin(ID)() { return X; }
}

mixin MakeFun!("one", 1); // int one() { return 1; }

Alas I get:
makefunc.d(3): Error: no identifier for declarator `int`
makefunc.d(3): Error: found `{` when expecting `;`
makefunc.d(3): Error: declaration expected, not `return`
makefunc.d(4): Error: unrecognized declaration

Is there a shorter way than building the entire function 
definition as a string mixin? As in:

mixin template MakeFun(string ID, int X)
{
   import std.format;
   mixin(format("int %s() { return %s; }", ID, X));
}

mixin MakeFun!("one", 1);

Meta <jared771 gmail.com> writes:

On Wednesday, 21 February 2018 at 22:11:04 UTC, Jean-Louis Leroy 
wrote:
 Here's what I am trying to do:

 mixin template MakeFun(string ID, int X)
 {
   int mixin(ID)() { return X; }
 }

 mixin MakeFun!("one", 1); // int one() { return 1; }

 Alas I get:
 makefunc.d(3): Error: no identifier for declarator `int`
 makefunc.d(3): Error: found `{` when expecting `;`
 makefunc.d(3): Error: declaration expected, not `return`
 makefunc.d(4): Error: unrecognized declaration

 Is there a shorter way than building the entire function 
 definition as a string mixin? As in:

 mixin template MakeFun(string ID, int X)
 {
   import std.format;
   mixin(format("int %s() { return %s; }", ID, X));
 }

 mixin MakeFun!("one", 1);

Mixins have to be full declarations. You can't mix in bits and 
pieces... except when you can:

import std.stdio;

void main()
{
     enum teste = "asdf";
     string s = mixin("teste");
     writeln(s); //Prints "asdf"
}

It looks like a grammar error as opposed to a semantic one. D's 
grammar just doesn't support `mixin` in the function name 
position. One way you can make it a little more palateable:

mixin template MakeFun(string ID, int X)
{
     import std.format;
     mixin(q{ int %s { return %s; } }.format(ID, X));
}

`q{}` denotes a token string that must contain valid tokens (I'm 
not sure if the available compiler implementations actually 
enforce this), and I _think_ token strings will be properly 
syntax-highlighted by most tools.

https://dlang.org/spec/lex.html#token_strings

Adam D. Ruppe <destructionator gmail.com> writes:

On Wednesday, 21 February 2018 at 22:22:55 UTC, Meta wrote:
 Mixins have to be full declarations.

They need to be full declarations, full statements, or full 
expressions, depending on the context where they appear.

     string s = mixin("teste");

so that is a full expression and thus legal.

Basile B. <b2.temp gmx.com> writes:

On Wednesday, 21 February 2018 at 22:22:55 UTC, Meta wrote:
 (I'm not sure if the available compiler implementations 
 actually enforce this)

Yes it does, example

```
enum s = q{€};
```

gives: `Error: character 0x20ac is not a valid token`