https://github.com/jrincayc/ucblogo-code
Revision 8d03f497146e641d7c3785ab2562b5148584fb3d authored by Joshua Cogliati on 22 November 2020, 22:08:40 UTC, committed by GitHub on 22 November 2020, 22:08:40 UTC
ISSUE-63: Exit getFromWX_2 input loop on pause character sequence.
Tip revision: 8d03f497146e641d7c3785ab2562b5148584fb3d authored by Joshua Cogliati on 22 November 2020, 22:08:40 UTC
Merge pull request #64 from dmalec/ISSUE-63
Merge pull request #64 from dmalec/ISSUE-63
Tip revision: 8d03f49
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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