🚀 go-pugleaf

On 3 Mar 90 03:06:41 GMT, Clifton_RL@admdev.cut.oz said:

Clifton> IMPLIED DO-LOOP STATEMENT

Clifton> We could use the implied do-loop construction.  For example:

Clifton> 	(((C(I,J)=A(I,K)*B(K,J) ,K=1,M) ,I=1,M) ,J=1,M)

Clifton> This clear statement would replace the familiar clutter of:

Clifton> 	DO J etc
Clifton> 	 DO I etc
Clifton> 	  DO K etc
Clifton> 	   C(I,J)= etc
Clifton> 	  ENDDO
Clifton> 	 ENDDO
Clifton> 	ENDDO

Clifton> How about it?

Its mostly just a matter of taste (which means others are sure to
disagree), but I find the DO-ENDDO to be clearer than the implied
DO construct you show.  Longer, true, but I wouldn't call it cluttered.
Perhaps it's just because I'm used to it.

The real test comes when things get more complicated.  You showed just
about the simplest possible do loop.  How about when you replace the
inner core with something with multiple statements - perhaps a block
if (or even something with statement labels and G*TO statements :-)).
Or what happens when there are statements in some of the intermediate
level DO's.  Certainly you COULD write such things in an implied DO
notation, but I think they will be very hard to read, particularly
when the loop contents get large enough that the J=1,M or whatever
is several lines below the first reference to the J.  That would mean
you could not read the code sequentially, but would have to scan ahead
to figure out what this J thing was. Possible, but awkward.
--

Richard Maine
maine@elxsi.dfrf.nasa.gov [130.134.64.6]