go/ast, go/parser: parse doc/comment for stmt

[dugenkui03]

background

I'd like to analysis the go source code by go parse and get important info represented by File.

But I find that the info of doc/comment will not assign to Stmt.

proposal

I propose change Stmt from

type Stmt interface {
	Node
	stmtNode()
}

to

type Stmt interface {
	Node
	stmtNode()
	SetDoc(*CommentGroup)
	SetComment(*CommentGroup)
}

demo

Code like below:

...

func testFunc() {
	// first lead doc
	sprintf := fmt.Sprintf("%s", 222) // first line comment
	// second lead doc
	print(sprintf) // second line comment
}
...

will parse and get FuncDecl like that

[qiulaidongfeng]

Changing the export API violates the go1 compatibility commitment.

[mvdan]

This problem has been known for a long time; for example, see #20744.

@adonovan has a work in progress solution at https://go-review.googlesource.com/c/go/+/429639, although I don't think it has a tracking issue.

Personally, I don't think this proposal is the right approach, and it's not nearly detailed enough to really tell how it would work beyond adding a bit of API.

[adonovan]

The previous two comments are correct: we can't change the interface, and we have a different solution for comments (that has been moving slowly but is not forgotten). So I think we must reject this proposal.

[dugenkui03]

@qiulaidongfeng Thanks for you remind "go1 compatibility commitment"

@mvdan @adonovan thanks, I will close this issue, and this proposal should be continue in t https://go-review.googlesource.com/c/go/+/429639