Dijkstra-esque Guarded Commands in Squeak
Andrew C. Greenberg
werdna at gate.net
Mon Aug 23 01:06:50 UTC 1999
>Maybe this has some pedagogical value. It may also be a reasonably
>nice way to construct an if-then-else structure in squeak.
A kind squeaker observed in private correspondence that Squeak, of
course, has an if-then-else structure, to wit:
booleanExpression
ifTrue: [theThenThing]
ifFalse: [theElseThing]
I meant, really the if-then-elif-else-style structures of some other
imperative languages, for which squeak has no express elegant
counterpart (and of which folks have reasonably and firmly argued are
unnecessary as indicative of poor design or factoring). Thus:
{[theIfExpr] -> [theThenThing]
.[theElif1Expr] -> [theElIf1Thing]
.[theElif2Expr] -> [theElIf2Thing]
.[theElif3Expr] -> [theElIf3Thing]
.. . .
.[theElifnExpr] -> [theElIfnThing]
.[true] -> [theElseThing]
} if
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