p j wrote:
> I'd also need to know whether specific
> conjunctions/adverbs evaluate to a verb or noun (after
> their arguments processed).  I'm guessing there's only
> 2 ways to find out: 1. execute the conjunction (not
> safe obviously), or 2. Would need J support for
> classifying user-defined conjunctions by their
> possible return types.  

In general, the only completely valid way to determine
adverb/conjunction result type is to evaluate the adverb
or conjunction.  J itself does not know except through
evaluation.

However, you don't have to be completely general when
transforming programs.  It's perfectly alright to punt
at some point -- you don't have to solve the halting
problem, you just need to document where you give up.

A classic example of a conjunction which can return any
of the four major syntactic types is :
 0 :'', 1 :'', 2 :'' and 3 :'' all have different syntactic
types (by the way: all these functions have empty domains
because none produce a result -- but it's the : conjunction
I'm using as an example here, not the result of :).

A slightly more abstract case of this would be 2 :'m :n'

-- 
Raul



----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm

Reply via email to