Generate "import C" for cgo

[dave]

Generate "import C" for cgo

[dave]

No, you're right - there's no support for this, but definitely something I'll add. I'll have to have a read up on the syntax to make a call on how to make it happen...

[dave]

How about:

• "C" import is added by simply using Qual("C", "foo") in your code, as is the case for all other imports.
• It's treated as a special case when the page renders
• The Qual method always renders the upper-case "C" (as is convention).
• Imports are usually aliased - with "C" the alias will be suppressed (not sure if this is a requirement?).
• The import is separated below the other imports.
• A new method CommentC() is added with the same functionality as "Comment()". The comment (or comments) are rendered directly above the import... So you'd get something like:

import (
    fmt "fmt"
    baz "foo.bar/baz"
)

// foo
/*
bar
baz
*/
import "C"

func main() {
    fmt.Println(C.create_object(), baz.Quz)
}

[pekim]

That all sounds good to me.

Imports are usually aliased - with "C" the alias will be suppressed (not sure if this is a requirement?).

I'm not sure either, but I've never seen an example of cgo usage with the import aliased. Suppressing the alias sounds like the right thing to do.

[dave]

Yes the only reason we always alias the imports is because we don't actually know the package name, so dropping the alias on "C" is perfectly fine. I should have some time tomorrow to implement this.

[dave]

Hey - a question: Are there times where you might want to import the "C" pseudo-package, but not reference it in code?

e.g.:

package foo

import "C"

func main() {
    // never use C
}

In this case would you use the import _ "C" syntax?

[pekim]

If there were to be such a scenario then it would likely be to control a compiler or linker flag, and the import would be preceded by some comment lines.

// #cgo LDFLAGS: -lpng
import "C"

I don't think that I'm likely to need this in my current use cases. But I can't rule it out.

I'm not sure whether import _ "C" would be recognised by the compiler for cgo purposes. I would need to try it with a simple use case. Unfortunately I won't be in a position to do that for about 10 or 11 hours.

[dave]

Yes it looks like "C" is indeed a special case, and can be imported without a "_" even without being used...

[dave]

I'm happy with this... Let me know if you think it needs any tweaks.

[dave]

BTW @pekim thanks very much for the excellent suggestion, and feel free to open issues if you have any more questions. I'm really glad you're enjoying my work!

[pekim]

I've just tried it out, and it works nicely. Thank you.

I appreciate that you tag releases, including v0.17.0 with these changes.