Multi-exit loops

[Alexis Layton]

In the most recent SIGPLAN Notices (Vol. 20, No. 11; November 1985) there
is what I consider to be an excellent article by P. A. Buhr entitled
"A Case for Teaching Multi-exit Loops to Beginning Programmers".
While he does make several good points about why beginning programmers should
learn these concepts, the bulk of the article is a very cogent argument about
why languages should support a multi-exit loop construct.  He differentiates
between the common of use of C's "break" statement (and equivalent statements
such as Ada's "exit") and a more syntactic loop-exiting statement which can
only occur in the "top-level" (so to speak) of the loop body.

While I primarily agree with his recommendations (and I hope new language
designers are familiar with his reasoning), the kind of loop construct involved
is too foreign to the style of C to integrate it in any way.  I fear that
attempts to use the preprocessor to enforce any kind of loop-like construct
are doomed to produce confusing code.

					Alexis Layton
					Computer Corporation of America
					alex at cca-unix.ARPA
					decvax!cca!alex