[Aldor-l] [fricas-devel] Re: Package technicalities

[Ralf Hemmecke]

My last mail to fricas-devel since I agree with Bill that this is a sole 
Aldor question.

> I'm using aldor interpreter and there

Warning. The aldor interpreter is not very reliable. I wouldn't use it 
to simply #include your TypeFinder2.as file.

> %2>>  #include "TypeFinder2"
> Defined TypeFinder @ (S: Type) ->  (
>   with GetType: S ->  Type
>      ==  add ()
> )
>                                             Comp: 0 msec, Interp: 0
> msec
> "TypeFinder2.as", line 7:         GetType (x: S): Type == S
>                            .................^
> [L7 C18] #1 (Warning) Function returns a domain that might not be
> constant (which may cause problems if it is used in a dependent type).
>
> %3>>  import from TypeFinder(Integer)
>                                             Comp: 0 msec, Interp: 0
> msec
> %4>>  import from Integer
>                                             Comp: 10 msec, Interp: 0
> msec
> %5>>  GetType 2
>    () @ Type
>                                             Comp: 0 msec, Interp: 0
> msec

If at all then you would have to write

#include "aldor"
#inlcude "aldorinterp"
#include "TypeFinder2"

The reason is that aldorinterp.as provides "print" which is required by 
the interpreter, but not by default provided by the aldor library.

> I expected GetType 2 to return something like
>    Integer @ Type

But for that to work "Type" must be of type "OutputType". Since "Type" 
does not export anything, you are out of luck.

If you want, you can achieve an output of "Integer @ Type". It would be 
more of a hack then proper Aldor programming, since you must figure out 
how a domain can print its own name.

Look for the function name$Trace at
https://svn.origo.ethz.ch/algebraist/trunk/aldor/lib/aldor/src/util/ald_trace.as
It provides this functionality.

But again a warning. You cannot rely on correct behaviour of that 
function, since it is not specified in the Aldor User Guide!
It's rather deep knowledge of the compiler internals.

Ralf