racket / racket/htdp

[ASL] Value of `set!`

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bug enhancement
Dominant language
Racket
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9h 41m
Merged PRs (30d)
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Description

The value of calling set! appears to be (some form of) void:

> (define x 1)
> (set! x 2)
(void)

but doesn't behave as void or (void):

> (void? (set! x 3))
#false
> ((set! x 3))
function call: expected a function after the open parenthesis, but received (void)

This is causing confusion for students because they have to use something like (begin (set! x y) (void)) even though it looks unnecessary.

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  3. Fork the repository and make your change on a branch.
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Research direction

Reproduce the examples in the issue in the ASL teaching language, starting with the behavior of set! and comparing it with void and (void). Locate the ASL implementation and its existing tests; done means the set! result has consistent, documented behavior and the reported examples no longer cause confusion.

Written by the indexing model from the issue text.

Assessment

Domain
compilers
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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