Feature: Hindley Milner polymorphic type inference (cl-typeck) #16

New Issue

j · 2024-07-31T08:42:57Z

j commented

2024-07-31 08:42:57 +00:00

Feature Progress

Decide on typing rules for each kind of expression
Implement a variant of a HM algorithm that operates on the typed AST

Feature description

This feature will allow users to omit type annotations wherever the inference algorithm can determine the type.

Problems

Generalized type inference is undecidable. Conlang is pretty limited, so it may be doable.
Where is it legal to omit type information? How would that be decided?
Are untagged polymorphic functions desirable?

Example

fn hex(n: u64) -> String {
    // ...
}

fn main() {
    let x = hex(1000); // x: String
    let y = 10 + 3;    // y: {int}
    print(hex(y), x);  // y: u64

# Feature Progress  - [ ] Decide on typing rules for each kind of expression - [ ] Implement a variant of a HM algorithm that operates on the typed AST # Feature description  This feature will allow users to omit type annotations wherever the inference algorithm can determine the type. # Problems - Generalized type inference is undecidable. Conlang is pretty limited, so it may be doable. - Where is it legal to omit type information? How would that be decided? - Are untagged polymorphic functions desirable? # Example  ```rust fn hex(n: u64) -> String { // ... } fn main() { let x = hex(1000); // x: String let y = 10 + 3; // y: {int} print(hex(y), x); // y: u64 ```

j added the

enhancement

label 2024-07-31 08:42:57 +00:00

j added this to the Static Analysis project 2024-07-31 08:59:53 +00:00

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