Type-introspection with macros

[johnpyp]

🙋 feature request

Support introspecting types, annotations, and more in macros. My main theoretical usecase is writing a zod-type library that doesn't require advanced conditional typescript, and can compile to the most performant version of serializers and deserializers. Very similar to Serde.

🤔 Expected Behavior

I don't know exactly the semantics of how this behavior might work, but here's an example of what I'd like to be able to do:

import { Serde, Field } from 'serde'
import {  objectDeserialize, jsonDeserialize } from 'serde' with { type: 'macro' }

@Serde
class MyData {
  @Field({ minLength: 10 })
  public password: string

  @Field({ validateEmail: true })
  public email: string;
}

const myResponse = Response(...)

// Deserialize from string
const jsonDecoded = jsonDeserialize<MyData>(await myResponse.text())

// Deserialize from untyped object
const objectDeserialize = objectDeserialize<MyData>(await myResponse.json())

😯 Current Behavior

Can't introspect type arguments to be able to code-gen against it

💁 Possible Solution

Not really sure how to implement it

🔦 Context

See the example above :)

💻 Examples

See the example above :)