Builtin previewer for vim.fn.taglist() picker

[tronikelis]

Hey, so I want to create a simple picker which lets me select items from the list generated by vim.fn.taglist()

This is what I have currently

    local fzf_lua = require("fzf-lua")
    local builtin = require("fzf-lua.previewer.builtin")

    local keyword = vim.fn.expand("<cword>")
    local matches = vim.fn.taglist(string.format("^%s$", vim.fn.escape(keyword, "^$")), vim.fn.expand("%:p"))

    local rows = {}
    for _, v in ipairs(matches) do
        table.insert(
            rows,
            string.format("%s\t%s %s\t%s", v.name, v.kind, vim.fn.fnamemodify(v.filename, ":~:."), v.cmd)
        )
    end

    local CtagsPreviewer = builtin.buffer_or_file:extend()

    function CtagsPreviewer:new(o, opts, fzf_win)
        CtagsPreviewer.super.new(self, o, opts, fzf_win)
        setmetatable(self, CtagsPreviewer)
        return self
    end

    function CtagsPreviewer:parse_entry(entry_str)
        local filename, excmd = entry_str:match(".*\t. (.*)\t(.*)$")

        vim.api.nvim_win_call(self.win.preview_winid, function()
            vim.fn.search(excmd:sub(2, -2), "cw")
        end)

        local cursor = vim.api.nvim_win_get_cursor(self.win.preview_winid)

        return {
            path = filename,
            line = cursor[1],
            col = cursor[2] + 1,
        }
    end

    fzf_lua.fzf_exec(rows, {
        prompt = string.format("%s> ", keyword),
        previewer = CtagsPreviewer,
    })

Image

This kinda works, but the problem I have is that sometimes the correct line is selected, sometimes not. I read some of the previewer code and I guess it's due to caching and parse_entry being called before the actual buffer contents are filled.

What I need is to call vim.fn.search(cmd) on each preview window for the cursor to go to the line. What is the simplest way to achieve this?

Some pseudocode what I need:

Previewer:on_window_change()
vim.api.nvim_win_call(self.win, function() vim.fn.search(self.parsed_entry.cmd) end)
end

I know I can just use the builtin tags_grep_cword, but it has worse filtering than taglist()

[ibhagwan]

Have you tried extending the preview class?
https://github.com/ibhagwan/fzf-lua/wiki/Advanced#preview-nvim-builtin

[tronikelis]

Have you tried extending the preview class? Wiki: Advanced (preview nvim builtin)

Yeah, I extended the local CtagsPreviewer = builtin.buffer_or_file:extend() builtin buffer_or_file previewer

[ibhagwan]

Have you tried extending the preview class? Wiki: Advanced (preview nvim builtin)

Yeah, I extended the local CtagsPreviewer = builtin.buffer_or_file:extend() builtin buffer_or_file previewer

Why don’t you extend the tags previewer? IIRC The code for it also uses fn.search, maybe with a small modification it will do exactly what you want?

[tronikelis]

Why don’t you extend the tags previewer?

Oh wow, I haven't noticed that this previewer exists 🤦 , this looks like exactly what I need

[tronikelis]

Works perfectly, thanks man, my love for this plugin grows everyday

[tronikelis]

If anyone stumbles upon this discussion, this is what I have currently:

local fzf_lua = require("fzf-lua")
local builtin = require("fzf-lua.previewer.builtin")
local ansi_codes = fzf_lua.utils.ansi_codes

local function parse_entry(entry_str)
    local filename = entry_str:match("^.+ . (.+): /(.+)/$")
    local ctag = require("fzf-lua.path").entry_to_ctag(entry_str, false)
    return filename, ctag
end

local CtagsPreviewer = builtin.tags:extend()

function CtagsPreviewer:new(o, opts, fzf_win)
    CtagsPreviewer.super.new(self, o, opts, fzf_win)
    setmetatable(self, CtagsPreviewer)
    return self
end

function CtagsPreviewer:parse_entry(entry_str)
    local filename, ctag = parse_entry(entry_str)

    return {
        path = filename,
        ctag = ctag,
    }
end

local function goto_match(entry_str)
    local filename, ctag = parse_entry(entry_str)
    vim.cmd.e(filename)
    vim.api.nvim_win_set_cursor(0, { 1, 0 })
    vim.fn.search(ctag, "W")
end

vim.api.nvim_create_user_command("Taglist", function(ev)
    if vim.bo.buftype ~= "" then
        print("Taglist requires normal buffer")
        return
    end

    local keyword = ev.fargs[1]
    local matches = vim.fn.taglist(string.format("^%s$", vim.fn.escape(keyword, "^$")), vim.fn.expand("%:p"))

    local rows = {}
    for _, v in ipairs(matches) do
        table.insert(
            rows,
            string.format(
                "%s %s %s: %s",
                ansi_codes.magenta(v.name),
                ansi_codes.yellow(v.kind),
                vim.fn.fnamemodify(v.filename, ":~:."),
                ansi_codes.grey(v.cmd)
            )
        )
    end

    fzf_lua.fzf_exec(rows, {
        prompt = string.format("%s> ", keyword),
        previewer = CtagsPreviewer,
        winopts = {
            title = "Taglist",
        },
        actions = {
            default = function(item)
                goto_match(item[1])
            end,
            ["ctrl-s"] = function(item)
                vim.cmd("new")
                goto_match(item[1])
            end,
            ["ctrl-v"] = function(item)
                vim.cmd("vertical new")
                goto_match(item[1])
            end,
        },
    })
end, {
    nargs = 1,
})