GoAddTags: tag options

[tobstarr]

At least for my workflow it would be nice to be able to also provide e.g. the omitempty option when adding a json tag to a struct field.

I would propose to change the behaviour of GoAddTags json,omitempty to produce json:"name,omitempty" instead of json,omitempty:"name" but I do not know if there are cases where one actually would want to add a tag including a comma character.

[fatih]

Hi @tobstarr

This and the second PR (#984) you opened, I wanted to do in the next release ;) I didn't wanted to put a lot of features. So adding them one by one is the way to go 👍

Tag options is easy, however for the second one we need to parse the string (might be a little bit complicated, but doable). I'll keep an eye on this. If someone else want to tackle it feel free to pick it up, but let me know before if you do it.

[fatih]

Fixed with #1204 please, feel free to test and reopen if it's not the case.

[tobstarr]

@fatih is it intended that GoAddTags json,omitempty only works if the tag is already present? In that case things work fine, otherwise nothing happens (but something is happening as the vim buffer is then marked as changed - +)

[fatih]

Yeah it only works if it exists. Previously it was the opposite. The buffer changes because gomodifytags changes the file again, thus the creation time changes as well. Open an issue to https://github.com/fatih/gomodifytags to track if you want :)

[tobstarr]

Any particular reason for that? I would find it really handy for GoAddTags json,omitemty to also create the tag of it does not exist.

I just checked gomodifytag and the call gomodifytags -file main.go -add-tags json -struct User -add-options json=omitempty would do the trick (add the tag with the option if it does not exist).

Behaviour before was not the opposite, but that it created this: json,omitempty:"name".

[fatih]

When I mean oppposite, the current implementation was like you said. I've removed it because I wanted to make it explicitly. It's very easy to change it because I've like that previously. I'm not sure why I reverted it (don't remember now). Let me check it again.

[gitsang]

I write a function to implement it (using fatih/gomodifytags)

:command -range -nargs=* GoTagsAdd <line1>,<line2>call GoTagsAdd(<f-args>)
function! GoTagsAdd(...) range
    let filename = expand('%:t')
    let line = a:firstline . ',' . a:lastline
    let cmds = ['!gomodifytags']
    call add(cmds, '-file')
    call add(cmds, filename)
    call add(cmds, '-line')
    call add(cmds, line)
    call add(cmds, '--skip-unexported')
    call add(cmds, '-w --quiet')
    let cmd = join(cmds, " ")

    if a:0 > 0
        let tags = a:1
        if tags != '--'
            call add(cmds, '-add-tags')
            call add(cmds, tags)
        endif
    else
        call add(cmds, '-add-tags json')
    endif

    if a:0 > 1
        let options = a:2
        if options != '--'
            call add(cmds, '-add-options')
            call add(cmds, options)
        endif
    else
        call add(cmds, '-add-options json=omitempty')
    endif

    if a:0 > 2
        let transform = a:2
        if transform != '--'
            call add(cmds, '-transform')
            call add(cmds, transform)
        endif
    else
        call add(cmds, '-transform camelcase')
    endif

    execute join(cmds, " ")
endfunction

It seems like