codecs
with morphs, I am thinking of arktype types as sort of input/output functions
for
const t = type(...)
t.allows(input) tells if you if input is the right shape
t(input) takes input and turns it into output (or errors)
is there a way to extract a def/type of the input type (pre-morph) vs output type (post-morph)?171 Replies
I saw
t.in and t.out but I don't think they give me what I want, or at least their types don't
if a type has no morphs, then in/out would be ~equivalentI am prob misunderstanding arktype internals but my assumption was that the 6th assertion would be false
might better describe the behavior
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I actually made this improvement recently to help show the discrepancy bewteen the type information that is available at runtime and what we can statically determine.
@frolic I'm guessing in your case,
.out is typed as unknown. That's because if you just apply an arbitrary transformation, we can infer the return statically, but at runtime there's no way to know what you expect your function to return, so .out is just unknown.
If you want a validated output type, you can .pipe to another type or .to(def), then it will infer the validated output and make it available at runtimeI am rethinking my API around this because I don't think I can get what I want with just a single type with morphs
Well yeah if you need the validated output you'd need a type for it just like the input
oh I see what you're saying now
would it make sense to allow describing the output type of morphs?
wondering if its a small enough API change that enables a runtime validator for output
You're misunderstanding, this is already possible you just have to provide one
Pipe to a type
You can pipe from an input, to a morph, then to a type
Then it will be available and inferred
at a property level?
Types are composable, so yeah. You could do it with nested tuple expressions although like I said this is the sort of territory where chaining is usually more natural
like
string.integer for example, string is the input type and it morphs to an integer, but does it also pipe to number?The builtin keyword doesn't right now because I don't want to perform redundant validation and it's relatively rare people need to extract
in/out if they already have the inferred type.
That said I do want to add a feature that allows you to essentially "cast" the output type of a morph so you can introspect it without adding validation stepsokay another question/approach: can I validate that a type def has no morphs?
as in no chance of anything inside resolving to
unknownYeah there is a
.internal.includesMorphs()