[patch][commit] New (if (...) (...) (...)) Test Allowed at Top Level of the Input

[Dave Brolley]

Thien-Thi Nguyen wrote:

>why not allow computed `include' instead?  (perhaps that is already
>supported?)  something like:
>
>(include EXPR)
>
>then EXPR can be all manner of `if', `cond' or whatever.  e.g.:
>
>(include (if (application-is? SID-SIMULATOR)
>             "sid-macros.cpu"
>             "sim-macros.cpu"))
>
>(include (cond ((application-is? SID-SIMULATOR)
>                "sid-macros.cpu")
>               (else "sim-macros.cpu")))
>
>(include (case (application->symbol APPLICATION-OBJECT)
>           ((SIMULATOR) "sid-macros.cpu")
>           (else "sid-macros.cpu")))
>
>  
>
The point isn't really the (include "..."). That's just what I happened 
to use the 'if' capability for. The true and false expressions could 
theoretically be any valid top level CGEN construct. Implementing 
conditional capability for them all seems like a lot more work for no 
gain and may not even make sense in some cases. Also 'cond' or 'case' 
could easily be added as top level tests if necessary.

Dave