I'd like a predicate that checks whether a number is a Float. Here's what I tried:
(: amplitudes/t (Listof Float))
(define amplitudes/t
(cond [(andmap inexact-real? amplitudes)
amplitudes]
[(error 'impossible "Make TR happy")]))
But I get:
Type Checker: Expected Coefficients, but got (U Null (Pairof Inexact-Real
(Listof Inexact-Real))) in: amplitudes
Examining the difference between Inexact-Real and Float yields this:
> (:type Float)
(U Float-Positive-Zero Float-Negative-Zero Float-Nan Positive-Float
Negative-Float)
> (:type Inexact-Real)
(U Float-Positive-Zero Float-Negative-Zero Float-Nan Positive-Float
Negative-Float Single-Flonum-Positive-Zero Single-Flonum-Negative-Zero
Single-Flonum-Nan Positive-Single-Flonum Negative-Single-Flonum)
...which actually made me laugh out loud. Is there a predicate I can use
instead of 'inexact-real?' that checks whether a number belongs to the type
Float?
(The larger picture here is that TR *had* this type information--namely, that
amplitudes is a (Listof Float), but it looks like it's getting lost by an
overly-complex expansion of match.)
John
smime.p7s
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