User defined statements for D like seed have?

[janderson]

Jarrett Billingsley wrote:
> "dennis luehring" <dl.soluz at gmx.net> wrote in message 
> news:esncoo$pid$1 at digitalmars.com...
>> example how a for statement is declared
>> http://seed7.sourceforge.net/examples/declstat.htm
>>
>> ok i know that seed is an interpreter language but maybe there is a way 
>> walter can allow something like this for his buildin statements
>>
>> or even better the case statement
>>
>> http://seed7.sourceforge.net/manual/stats.htm#case-statement
>>
>> as a statement-template wich can produce (with the help of the awaited 
>> static foreach) a nice objectfactory from a tuple or something like this
>>
>> ciao denni
> 
> Stuff like this has been requested several times, but the same problem 
> prevents these suggestions from being implemented: they break the separation 
> of syntactic and semantic analysis.  This increases the complexity of the 
> compiler greatly.
> 
> Now, some level of "custom code" may become available if/when D gets 
> Lisp-style macros, which will (hopefully) allow for custom generation and 
> reorganization of code by other code. 
> 

You should be able to do this now with mixins, although its not the 
neatest way to do things.

-Joel