Extension: Alternate string literal syntax (mixins, DSLs)

[Kristian Kilpi]

On Sun, 11 Feb 2007 17:55:39 +0200, Kristian Kilpi <kjkilpi at gmail.com>  
wrote:
>
> String literals with mixins are a bit awkward sometimes (editor  
> highlighting etc).
>
> Some special marks -- I use @{ }@ here -- could be used to mark a part  
> of a source file as a string literal, just like /* */ marks a part of  
> code as a comment. For example:
>
>    mixin(
>      @{
>        //this is a string literal block
>        if(...) {
>          ...
>        }
>      }@
>    );
>
> The @{ }@ marks have a close relation, of course, with quotation marks  
> "". But because there is a starting mark and an ending mark, you can  
> nest them. (And because they are used to mark a part of a file as a  
> string literal, they are not actually the part of the 'working code'  
> just like the "" literals are, if you get what I'm trying to say.)
>
> E.g.
>
>    alias @{
>      str = @{ foo }@ ~ @{ bar }@;
>      str ~= "blah";
>      if(...) {
>        ...
>      }
>    }@ MyCode;
>
>     mixin(MyCode);

I think the following would also be nice (in addition to other ideas  
suggested in this thread):

   template MyTemplate() {...}

   alias @{ ... }@ MyAlias;

   @{
     val = $MyTemplate!();

     str = $MyAlias;
   }@

And the string literal would be treaded by the compiler as:

   @{
     val = }@ ~ MyTemplate!() ~ @{

     str = }@ ~ MyAlias ~ @{
   }@

(I.e. "val = " ~ MyTemplate!() ~ "str = " ~ MyAlias ~ "")

I use $ here, but @ or some other (unambiguous) character could be used  
instead, of course.


In addition, the compiler could convert numeric literals automatically to  
strings:

   const double v = 1.0;

   int MyFunc() { return 10; }

   @{ val = $MyFunc() + $v; }@

->

   " val = 10 + 1.0; "


I think the $ marks inside nested @{ }@s should not be converted. For  
example:

   const int v = 1;

   @{
     val = $v;

     @{
       val2 = $v;
     }@
   }@

->

   "
     val = 1;

     @{
       val2 = $v;
     }@
   "