https://github.com/jrincayc/ucblogo-code
Revision 68a93248641e91314d2700e8a3c6ba0c73ba5422 authored by Joshua J. Cogliati on 27 December 2021, 16:56:40 UTC, committed by Joshua J. Cogliati on 27 December 2021, 16:56:40 UTC
1 parent e3a5d7a
Tip revision: 68a93248641e91314d2700e8a3c6ba0c73ba5422 authored by Joshua J. Cogliati on 27 December 2021, 16:56:40 UTC
Updating version to 6.2.2pre1
Updating version to 6.2.2pre1
Tip revision: 68a9324
dmaybeoutput
.MAYBEOUTPUT value (special form)
works like OUTPUT except that the expression that provides the
input value might not, in fact, output a value, in which case
the effect is like STOP. This is intended for use in control
structure definitions, for cases in which you don't know whether
or not some expression produces a value. Example:
to invoke :function [:inputs] 2
.maybeoutput apply :function :inputs
end
? (invoke "print "a "b "c)
a b c
? print (invoke "word "a "b "c)
abc
This is an alternative to RUNRESULT. It's fast and easy to use,
at the cost of being an exception to Logo's evaluation rules.
(Ordinarily, it should be an error if the expression that's
supposed to provide an input to something doesn't have a value.)
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