racket/typed-racket

case-lambda allows multiple cases with the same arity

Aperta

#517 aperta il 24 mar 2017

 (5 commenti) (0 reazioni) (0 assegnatari)Racket (106 fork)github user discovery
arrowgood first issue

Metriche repository

Star
 (576 stelle)
Metriche merge PR
 (Merge medio 11g 14h) (1 PR mergiata in 30 g)

Descrizione

[I originally opened this as an issue for racket, but it more clearly violates the docs for typed/racket.]

Although for racket it doesn't seem explicitly forbidden, the typed/racket docs say:

Note that each formals must have a different arity.

Should this perhaps be an expansion-time error:

> (case-lambda [([z : Zero]) z]
               [([o : One]) o])
- : (-> Zero Zero)

This came up because a student encountering the case-> type constructor wondered whether case-lambda would provide overloading by type.

Guida contributor