Type Hints

[Jason2605]

Type Hints

Resolves: #670

What's Changed:

• Allow the compiler to recognise (and ignore) type hints. This will allow third party type checkers to be created

The hints themselves are essentially a comment, but will need to be a valid identifier token otherwise the compiler will fail.

Syntax

def test(): string {
    return "test";
}

class Test {
    someMethod(): number {
        return 10;
    }
}

const test: string = "Hello!";

// `?int` could denote int OR nil
var multiple: ?int, variables: number = 10;

const [unpacking: list] = [["nested list"]];

Type of Change:

• Bug fix
• New feature
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Housekeeping:

• Tests have been updated to reflect the changes done within this PR (if applicable).
• Documentation has been updated to reflect the changes done within this PR (if applicable).

Screenshots (If Applicable):

[Jason2605]

Dunno what your guys thoughts are on this @liz3 @briandowns ?

Would allow us to create a static analyser outside of the Dictu codebase (potentially written in Dictu :O) similar to MyPy and others

[liz3]

I don't mind something like that as long as its optional. Good static analysers are able to do this without hints by inferring based on default values, assignments etc. By the point good static analysers start failing because of dynamic evaluation those types usually are not helping.
Amongs my peers i have the unpopular opinion of not liking typescript for example. Imo it does not add actual value since most bugs are logic errors which a static analyser cannot catch.
That being said i do like them once the vm(runtime) can use them to provide a performance advantage through making assumptions it cannot do otherwise.

The TL'DR for me is: I think in the current form(optional) they are okay but nothing i would put too much value on.

[briandowns]

I'm with @liz3 . I don't think I'd use them much unless I'm writing a huge code base and it'd be a pain to track back through a ton of files to figure out what's what. Super cool feature though from a parser / language perspective though.