import all symbols from a module

[sswam]

I'm just learning a bit of Love2d and Lua, and I like it so far, but I'm not a fan of writing `love.graphics` 500 times in my program for no good reason. It makes the code more laborious to write, and harder to read. I also prefer not to import all the functions I might want to use one by one. So I wrote a little function to import symbols, much like python's `from math import *`. (I also wrote something similar for JavaScript a while ago.) I'm aware that this is frowned upon for big projects, but I think it's awfully convenient for experimenting and messing around.

Example:

util.lua:

Code: Select all

function use(module, ...)
    for k,v in pairs(module) do
        if _G[k] then
            io.stderr:write("use: skipping duplicate symbol ", k, "\n")
        else
            _G[k] = module[k]
        end
    end
end

io.stdout:setvbuf("no")

use(math)
use(love.graphics)
gprint = love.graphics.print
use(love.audio)

main.lua:

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require "util"

function love.load()
    whale = newImage("whale.png")
    sound = newSource("whale.ogg", "stream")
    play(sound)
    print(sin(pi/6))
end

function love.draw()
    setColor(1, 0, 0)
    circle("fill", 300, 300, 200)
    setColor(1, 1, 1)
    draw(whale, -40, -50)
    gprint("Hello Whaled!", 400, 300)
end

[ReFreezed]

The problem with this approach is when there are name collisions, like with the print function in the example. A simple solution if you don't want to have "love.graphics" everywhere in the code is to use a shorter name:

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LG = love.graphics
function love.draw()
	print("Now drawing!")
	LG.print("Hello")
end

Both easy to write and read, and no name collisions.

[pgimeno]

My solution is to have this file called ns.lua:

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--[========================================================================[--

Abbreviate LÖVE namespaces as locals

Written by Pedro Gimeno Fortea, donated to the public domain.

Usage (copy-paste this line to every file needing the namespaces):

local la,le,lfs,lf,lg,li,lj,lk,lm,lmo,lp,ls,lsys,lth,lt,lw,ld,lto,lv = require'ns'()

--]========================================================================]--

return function() return
  love.audio, love.event, love.filesystem, love.font, love.graphics,
  love.image, love.joystick, love.keyboard, love.math, love.mouse,
  love.physics, love.sound, love.system, love.thread, love.timer, love.window,
  love.data, love.touch, love.video
end

This has the additional advantage that the namespaces are local, not global.

[milon]

My solution is to have this file called ns.lua:
...
This has the additional advantage that the namespaces are local, not global.

pgimeno, that's brilliant! Thanks for sharing.