Tips and Tricks

User contributed tips and tricks

keys

Utility function to specify many key combinations

It can sometimes be tedious to specify all key combinations which should trigger the loading of a plugin. To simplify that you can put the following utility function in your setup.

local M = {}

local function string_product(keys)
    if #keys == 1 then
        return keys[1]
    end
    local keys_copy = {}
    for _, key in ipairs(keys) do
        table.insert(keys_copy, key)
    end
    local product = {}
    local first = table.remove(keys_copy, 1)
    for _, a in ipairs(first) do
        if type(a) ~= 'string' then
            vim.cmd('echoerr "Not a valid keys table"')
        end
        for _, b in ipairs(string_product(keys_copy)) do
            table.insert(product, a .. b)
        end
    end
    return product
end

local function expand_keys(keys)
    if type(keys) == 'string' then
        return {keys}
    elseif type(keys[1]) == 'string' then
        return keys
    else
        return string_product(keys)
    end
end

M.get_keys = function(modes, keys)
    if type(modes) == 'string' then
        modes = {modes}
    end
    local combinations = {}
    for _, mode in ipairs(modes) do
        for _, v in ipairs(expand_keys(keys)) do
            table.insert(combinations, {mode, v})
        end
    end
    return combinations
end

return M

Previously you might have for example written:

use {
    'michaeljsmith/vim-indent-object',
    keys = {
        {'o', 'ii'},
        {'o', 'ai'},
        {'o', 'iI'},
        {'o', 'aI'},
        {'v', 'ii'},
        {'v', 'ai'},
        {'v', 'iI'},
        {'v', 'aI'},
    },
    wants = 'vim-textobj-user',
}

but with the above function you can write:

use {
    'michaeljsmith/vim-indent-object',
    keys = get_keys({'o', 'v'}, {{'a', 'i'}, {'i', 'I'}}),
    wants = 'vim-textobj-user',
}

which expands to the product of the individual keys in the specified modes.

Some examples:

local get_keys = require('packer').get_keys
print(vim.inspect(get_keys('n', 'a')))
print(vim.inspect(get_keys('n', {'a', 'b'})))
print(vim.inspect(get_keys('n', {{'a', 'b'}, {'c', 'd'}})))
print(vim.inspect(get_keys({'n', 'o'}, {{'a', 'b'}, {'c', 'd'}})))

which gives

{ { "n", "a" } }
{ { "n", "a" }, { "n", "b" } }
{ { "n", "ac" }, { "n", "ad" }, { "n", "bc" }, { "n", "bd" } }
{ { "n", "ac" }, { "n", "ad" }, { "n", "bc" }, { "n", "bd" }, { "o", "ac" }, { "o", "ad" }, { "o", "bc" }, { "o", "bd" } }

Running nvim without loading packer plugins

Since packer installs plugins to a folder which is in your runtime path by default, installed plugins will run even when loading another configuration. One way to remedy this is by invoking nvim with the --clean flag:

--clean

• Skips initializations from files and environment variables.
• No 'shada' file is read or written.
• Excludes user directories from 'runtimepath'

So if you wanted to run nvim with a minimal vimrc to debug a plugin for example, you would invoke nvim --clean -u min.vim