Alternate string literal syntax (with mixins)?

[Andrei Alexandrescu (See Website For Email)]

Johan Granberg wrote:
> Johan Granberg wrote:
> 
>> Kristian Kilpi 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);
>> Wouldn't it be a better solution if the escape syntax you described
>> represented a custom format that mixins was thought to handle? What I'm
>> thingking is something like lisps quotes, then the escaped code could be
>> tokenized and we could modify tokens instead of strings. (for a small
>> fraction of cases the string might be better but then we could have the
>> current syntax)
> 
> While I'm at it I might suggest using <[ and ]> as tokens instead of @{.
> This is the tokens used in nemerle (if I understood their manual right) and
> it is unnecessary to use a different token just because. 
> 
> http://nemerle.org/Syntax_extensions

Probably best is to use one group of symbols that nest naturally (e.g. 
[] or () or {}) and prefix them with something that unambiguously 
denotes a string:

alias ${
   ... anything with balanced {}'s ...
   ... or with unbalanced \{ and \}'s ...
} MyCode;

or:

alias $(
   ... anything with balanced ()'s ...
   ... or with unbalanced \( and \)'s ...
) MyCode;

or:

alias $[
   ... anything with balanced []'s ...
   ... or with unbalanced \[ and \]'s ...
] MyCode;

This should reasonably cover applications elegantly, especially because 
code tends to not have three kinds of unbalanced parens at the same time 
:o).


Andrei