Newsgroups: comp.lang.apl
Path: utzoo!censor!geac!itcyyz!yrloc!rbe
From: rbe@yrloc.ipsa.reuter.COM (Robert Bernecky)
Subject: copula vs branch in J
Message-ID: <1991May8.153919.5330@yrloc.ipsa.reuter.COM>
Reply-To: rbe@yrloc.ipsa.reuter.COM (Robert Bernecky)
Organization: SNake Island Research Inc, Toronto
Distribution: comp.lang.apl
Date: Wed, 8 May 91 15:39:19 GMT

MGF and LJD have been discussing how many branches can dance on the head
of one  or more copulas. I see no essential difference between the    
APL branch {label}
and the 
J  $.=. {label}

in terms of their theoretical wonderfulness, etc. J is perhaps a bit
simpler in this regard. 

Howsomeever, I think that J opens a can of worms with regard to data flow
analysis, in allowing a non-item argument to $. It wouldn't be so bad, in
some senses, if the suite were guaranteed to execute, without the possibility
of short-circuiting the execution partway through with another assignment to
$.

But it sure do make things messy for compilers....

Bob




Robert Bernecky      rbe@yrloc.ipsa.reuter.com  bernecky@itrchq.itrc.on.ca 
Snake Island Research Inc  (416) 368-6944   FAX: (416) 360-4694 
18 Fifth Street, Ward's Island
Toronto, Ontario M5J 2B9 
Canada