• Jack (26/26) May 10 2021 mixin template seems to allow only declarations so if I put a if
• Paul Backus (24/50) May 10 2021 You can do it with a string mixin:
• Jack (2/27) May 10 2021 sounds good, thanks!

Jack <jckj33 gmail.com> writes:

mixin template seems to allow only declarations so if I put a if 
or case-statement in the body it doesn't work. I'd like to make 
something like this work:

```d
             switch(code) {
                 case X, Y: // that specific case repeats alot in 
the code in different procedures
                   mixin handleXY;

                 default:
          }
```

then

```d
mixin template foo()
{
                 auto c = arr[i]; // arr and i are available at 
switch(code)'s scope
                 auto m = Message(...);

                 switch(code)
                 {
                     case BAA_A:  c.doSomething(m); break;
                     case BAA_B: c.doSomething(m); break;
                     default: assert(0, "error");
                 }
}
```

Paul Backus <snarwin gmail.com> writes:

On Monday, 10 May 2021 at 21:01:53 UTC, Jack wrote:
 mixin template seems to allow only declarations so if I put a 
 if or case-statement in the body it doesn't work. I'd like to 
 make something like this work:

 ```d
             switch(code) {
                 case X, Y: // that specific case repeats alot 
 in the code in different procedures
                   mixin handleXY;

                 default:
          }
 ```

 then

 ```d
 mixin template foo()
 {
                 auto c = arr[i]; // arr and i are available at 
 switch(code)'s scope
                 auto m = Message(...);

                 switch(code)
                 {
                     case BAA_A:  c.doSomething(m); break;
                     case BAA_B: c.doSomething(m); break;
                     default: assert(0, "error");
                 }
 }
 ```

You can do it with a string mixin:

```d
// Note: q{ ... } creates a "token string", a special kind of 
string literal
// that's used for code strings.
// See https://dlang.org/spec/lex.html#token_strings
enum string handleXY = q{
                 auto c = arr[i]; // arr and i are available at 
switch(code)'s scope
                 auto m = Message(...);

                 switch(code)
                 {
                     case BAA_A:  c.doSomething(m); break;
                     case BAA_B: c.doSomething(m); break;
                     default: assert(0, "error");
                 }
};
```

Usage:

```d
case X, Y:
     mixin(handleXY);
```

Jack <jckj33 gmail.com> writes:

On Monday, 10 May 2021 at 21:10:13 UTC, Paul Backus wrote:
 On Monday, 10 May 2021 at 21:01:53 UTC, Jack wrote:
 [...]

 You can do it with a string mixin:

 ```d
 // Note: q{ ... } creates a "token string", a special kind of 
 string literal
 // that's used for code strings.
 // See https://dlang.org/spec/lex.html#token_strings
 enum string handleXY = q{
                 auto c = arr[i]; // arr and i are available at 
 switch(code)'s scope
                 auto m = Message(...);

                 switch(code)
                 {
                     case BAA_A:  c.doSomething(m); break;
                     case BAA_B: c.doSomething(m); break;
                     default: assert(0, "error");
                 }
 };
 ```

 Usage:

 ```d
 case X, Y:
     mixin(handleXY);
 ```

sounds good, thanks!