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Smalltalk Complete Course / Exceptions & Resources

on:do:

Learn on:do: in Smalltalk with a construct-specific explanation, a unique example, a practical boundary, and a mastery check.

12 min read • Intermediate

on:do: is an atomic Smalltalk topic inside Exceptions & Resources. The example below uses the actual construct named by the lesson rather than a generic placeholder.

Focus on what on:do: changes: the input, binding, control path, object state, collection, runtime effect, or language contract. Then alter one value and verify that the behavior changes for a reason specific to this feature.

Topic-specific example

smalltalk-06-02-on-do.st
smalltalk Try It Live
[ 1 / 0 ] on: ZeroDivide do: [ :ex | #divisionError ].
Edge case / engineering note

Change the key input in this Smalltalk example and predict the result first; the named construct should be the reason the behavior changes.

Content source & attribution
Original Syntaxis Content · Original Syntaxis Content

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