Add more types and struct/parameter fix

[amaanq]

Supersedes #117

Checklist:

• All tests pass in CI.
• There are sufficient tests for the new fix/feature.
• Grammar rules have not been renamed unless absolutely necessary.
• The conflicts section hasn't grown too much.
• The parser size hasn't grown too much (check the value of STATE_COUNT in src/parser.c).

Closes #62
Closes #94
Closes #95
Closes #104
Closes #107

[aryx]

CI failure @amaanq

[amaanq]

Yeah...I forgot one file failed in the latest moby commit that the bigger PR had fixed as well - I added it to known-failures but I'll remove it in the followup PR! Sorry for the delay - on vacation right now 😁

[fsouza]

This seems incorrect. In the declaration:

func f2(a File, b, c, d Thing) int {}

b and c are identifiers, not types.

[fsouza]

Unfortunately, it looks like we can't reuse parameter_list for receiver, parameters and result.

Basically, the receiver cannot take a list for parameters, it's always a single parameter, but (x) means that x is a type_identifier, whereas (x y) means that x is identifier and y is type_identifier.

Now, for parameters vs result:

• (x int, y int) means the same thing in both cases (x and y are identifier, both ints are type_identifier)
• (x, y int) means the same thing in both cases (x and y are identifier, int is a type_identifier)
• (x, y) is invalid for parameters, but in the case result x and y are type_identifier (edit: this is wrong, I needed some sleep, they are the same)

I can try to send a PR later this week.

[zjykzk]

waiting for your PR

[fsouza]

Hmm I'm actually struggling with this one. I wanted to make something like:

func f1(x1, x2 int) {}
func f2(int, int) {}

Become:

(function_declaration
  (identifier)
  (parameter_list
    (parameter_declaration
      (identifier))
    (parameter_declaration
      (identifier)
      (type_identifier)))
  (block))

(function_declaration
  (identifier)
  (parameter_list
    (type_identifier)
    (type_identifier))
  (block))

But that's surprisingly tricky 😁

I tried:

    parameter_list: $ => seq(
      '(',
      optional(
        seq(
          choice(
            commaSep1(choice($.parameter_declaration, $.variadic_parameter_declaration)),
            seq(commaSep($._type)),
          ),
          optional(','),
        ),
      ),
      ')'
    ),

    parameter_declaration: $ => prec.left(-1, seq(
      field('name', $.identifier),
      optional(field('type', $._type)),
    )),

It would be somewhat easy to group parameters that "reuse" the type, but I feel like that isn't the correct approach.

I'll come back to this later this week, but if anyone has additional ideas, I'm all ears 😁

[amaanq]

#119

[fsouza]

@amaanq thanks for fixing it, I was definitely over complicating this lol