fix Guide spec for when' and unless'

Closes PR 13538
This commit is contained in:
Matthew Flatt 2013-02-21 08:17:51 -07:00
parent 772afd94fd
commit 71cffcffdf

View File

@ -98,20 +98,20 @@ computation produces an unknown number of results.
The @racket[when] form combines an @racket[if]-style conditional with The @racket[when] form combines an @racket[if]-style conditional with
sequencing for the ``then'' clause and no ``else'' clause: sequencing for the ``then'' clause and no ``else'' clause:
@specform[(when test-expr then-expr ...)] @specform[(when test-expr then-body ...+)]
If @racket[_test-expr] produces a true value, then all of the If @racket[_test-expr] produces a true value, then all of the
@racket[_then-expr]s are evaluated. The result of the last @racket[_then-body]s are evaluated. The result of the last
@racket[_then-expr] is the result of the @racket[when] form. @racket[_then-body] is the result of the @racket[when] form.
Otherwise, no @racket[_then-expr]s are evaluated and the Otherwise, no @racket[_then-body]s are evaluated and the
result is @|void-const|. result is @|void-const|.
The @racket[unless] form is similar: The @racket[unless] form is similar:
@specform[(unless test-expr then-expr ...)] @specform[(unless test-expr then-body ...+)]
The difference is that the @racket[_test-expr] result is inverted: the The difference is that the @racket[_test-expr] result is inverted: the
@racket[_then-expr]s are evaluated only if the @racket[_test-expr] @racket[_then-body]s are evaluated only if the @racket[_test-expr]
result is @racket[#f]. result is @racket[#f].
@defexamples[ @defexamples[