mirror of
https://github.com/tjdevries/advent-of-nvim.git
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yaya, much lua crashing
This commit is contained in:
TJ DeVries
@@ -1,13 +0,0 @@
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```lua
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-- Highlight when yanking (copying) text
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-- Try it with `yap` in normal mode
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-- See `:help vim.highlight.on_yank()`
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vim.api.nvim_create_autocmd('TextYankPost', {
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desc = 'Highlight when yanking (copying) text',
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group = vim.api.nvim_create_augroup('kickstart-highlight-yank', { clear = true }),
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callback = function()
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vim.highlight.on_yank()
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end,
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})
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```
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320
03 - Lua Crash Course.md
Normal file
320
03 - Lua Crash Course.md
Normal file
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# Lua Crash Course
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## Table of Contents
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- Comments
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- Variables
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- Control Flow
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- Modules
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- Functions
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- Metatables
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- Bonus :)
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## Background Info
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Lua is elegant
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- Lua uses "Mechanisms over Policies"
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- Lua is designed to be embedded
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- Lua is cool
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## Comments
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```lua
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-- This is a comment. It starts with two dashes
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--[[ This is also
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a comment.
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But it spans multiple lines!
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--]]
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```
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## Variables: Simple Literals
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```lua
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local number = 5
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local string = "hello, world"
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local single = 'also works'
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local crazy = [[ This
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is multi line and literal ]]
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local truth, lies = true, false
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local nothing = nil
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```
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## Variables: Functions
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```lua
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local function hello(name)
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print("Hello!", name)
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end
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local greet = function(name)
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-- .. is string concatenation
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print("Greetings, " .. name .. "!")
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end
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```
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## Variables: Functions
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```lua
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local higher_order = function(value)
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return function(another)
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return value + another
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end
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end
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local add_one = higher_order(1)
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print("add_one(2) -> ", add_one(2))
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```
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## Variables: Tables
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Effectively, Lua's only data structure.
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- Same structure is used for maps & lists
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## Variables: Tables
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As a list...
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```lua
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local list = { "first", 2, false, function() print("Fourth!") end }
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print("Yup, 1-indexed:", list[1])
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print("Fourth is 4...:", list[4]())
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```
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## Variables: Tables
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As a map...
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```lua
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local t = {
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literal_key = "a string",
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["an expression"] = "also works",
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[function() end] = true
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}
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print("literal_key : ", t.literal_key)
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print("an expression : ", t["an expression"])
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print("function() end: ", t[function() end])
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```
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## Variables: Not Covered
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- Thread
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- Userdata
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## Control Flow: `for`
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```lua
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local favorite_accounts = { "teej_dv", "ThePrimeagen", "terminaldotshop" }
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for index = 1, #favorite_accounts do
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print(index, favorite_accounts[index])
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end
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for index, value in ipairs(favorite_accounts) do
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print(index, value)
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end
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```
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## Control Flow: `for`
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```lua
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local reading_scores = { teej_dv = 10, ThePrimeagen = "N/A" }
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for index = 1, #reading_scores do
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print(reading_scores[index])
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end
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```
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Doesn't Print Anything - the "length" of the array is 0.
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We aren't using it as an array, we're using it as a map!
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## Control Flow: `for`
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```lua
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local reading_scores = { teej_dv = 9.5, ThePrimeagen = "N/A" }
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for key, value in pairs(reading_scores) do
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print(key, value)
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end
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```
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## Control Flow: `if`
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```lua
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local function action(loves_coffee)
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if loves_coffee then
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print("Check out `ssh terminal.shop` - it's cool!")
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else
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print("Check out `ssh terminal.shop` - it's still cool!")
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end
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end
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-- "falsey": nil, false
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action() -- Same as: action(nil)
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action(false)
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-- Everything else is "truthy"
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action(true)
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action(0)
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action({})
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```
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## Modules
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There isn't anything special about modules.
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Modules are just files!
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```lua
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-- foo.lua
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local M = {}
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M.cool_function = function() end
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return M
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```
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```lua
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-- bar.lua
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local foo = require('foo')
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foo.cool_function()
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```
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## Functions: Multiple Returns
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```lua
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local returns_four_values = function()
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return 1, 2, 3, 4
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end
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first, second, last = returns_four_values()
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print("first: ", first)
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print("second:", second)
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print("last: ", last)
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-- the `4` is discarded :'(
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```
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## Functions: Multiple Returns
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```lua
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local variable_arguments = function(...)
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local arguments = { ... }
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for i, v in ipairs({...}) do print(i, v) end
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return unpack(arguments)
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end
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print("===================")
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print("1:", variable_arguments("hello", "world", "!"))
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print("===================")
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print("2:", variable_arguments("hello", "world", "!"), "<lost>")
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```
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## Functions: Calling
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String Shorthand
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```lua
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local single_string = function(s)
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return s .. " - WOW!"
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end
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local x = single_string("hi")
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local y = single_string "hi"
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print(x, y)
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```
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## Functions: Calling
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Table Shorthand
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```lua
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local setup = function(opts)
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if opts.default == nil then
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opts.default = 17
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end
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print(opts.default, opts.other)
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end
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setup { default = 12, other = false}
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setup { other = true}
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```
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## Functions: Colon Functions
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```lua
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local MyTable = {}
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function MyTable.something(self, ...) end
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function MyTable:something(...) end
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```
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## Metatables
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```lua
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local vector_mt = {}
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vector_mt.__add = function(left, right)
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return setmetatable({
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left[1] + right[1],
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left[2] + right[2],
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left[3] + right[3],
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}, vector_mt)
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end
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local v1 = setmetatable({ 3, 1, 5 }, vector_mt)
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local v2 = setmetatable({ -3, 2, 2 }, vector_mt)
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local v3 = v1 + v2
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vim.print(v3[1], v3[2], v3[3])
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vim.print(v3 + v3)
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```
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## Metatables
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```lua
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local fib_mt = {
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__index = function(self, key)
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if key < 2 then return 1 end
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-- Update the table, to save the intermediate results
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self[key] = self[key - 2] + self[key - 1]
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-- Return the result
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return self[key]
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end
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}
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local fib = setmetatable({}, fib_mt)
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print(fib[5])
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print(fib[1000])
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```
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## Metatables
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Other notable fields:
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- `__newindex(self, key, value)`
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- `__call(self, ...)`
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## Quick Neovim Goodies
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```lua
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vim.keymap.set("n", "<space><space>x", "<cmd>source %<CR>")
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vim.keymap.set("n", "<space>x", ":.lua<CR>")
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vim.keymap.set("v", "<space>x", ":lua<CR>")
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```
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## Quick Neovim Goodies
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```lua
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-- Highlight when yanking (copying) text
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||||
-- Try it with `yap` in normal mode
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||||
-- See `:help vim.highlight.on_yank()`
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||||
vim.api.nvim_create_autocmd('TextYankPost', {
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||||
desc = 'Highlight when yanking (copying) text',
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||||
group = vim.api.nvim_create_augroup('kickstart-highlight-yank', { clear = true }),
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callback = function()
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vim.highlight.on_yank()
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||||
end,
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})
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```
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Reference in New Issue
Block a user