Is it possible to make a collapsing variables without making individual functions?

Question

I have a code that starts as a small amount of variables and makes more elements using those initial variables.

function new( x, y, width, height )
    local obj         


        

Answer 1

You could make use of metatables, more specific, the __newindex field:

(Well, need to combine it with the __index field, but eh)

function new(x, y, width, height )
    local object = {
        font = {}, padding = {}, text = {input=''}, -- tables themself are static
        -- also I assume text.input will change and has to stay the way it is
    }
    -- more static data here (yes yes, I know. The code is a bit ugly, but if it works fine...)
    object.config = { active = true, devmode = false, debug = false, id = gui.id(), type = 'textbox' }
    object.backspace = {key = false, rate = 3, time = 0, pausetime = 20, pause = true}
        object.border = { x = x, y = y, width = width, height = height }
    -- stuff that has to be calculated from the above variables goes below
    local border = object.border
    local function calculate()
        --border
        --body
        object.body = { x = border.x+1, y = border.y+1, width = border.width-2, height = border.height-2 }
        --font
        object.font.size = height-(math.floor(height/4)+1)
        object.font.height = love.graphics.setNewFont( object.font.size ):getHeight()
        --padding
        object.padding.height = math.floor(object.border.height*(2/29))
        object.padding.width = object.padding.height*3
        --text
        object.text.centerHeight = math.ceil(object.body.y+((object.body.height-object.font.height)/2))
        object.text.left = object.body.x+object.padding.width+object.padding.height
        --backspacing
        --config
    end
    calculate()
    local proxy = setmetatable({},{
        __index = object; -- proxy.abc returns object.abc (to get width, use proxy.border.width)
        __newindex = function(s,k,v)
            -- fires whenever 'proxy[k] = v' is done
            -- I assume you'll only change x/y/width/height, as other properties are dynamic
            -- Doing 'proxy.x = 123' is the same as 'object.border.x = 123' + recalculating
            object.border[k] = v -- Actually apply the change
            calculate() -- Recalculate the other properties that depends on the above
        end;
    })
    gui.add(object)
    return object.config.id
end

You can run code like proxy.x = 12 to edit the X property. All values will be recalculated. It's not the best, but your code a tiny bit annoying to improve. (But hey, if it works fine for you, it's good)

Note: You can only set x, y, width and height. You can get all properties the old way though, e.g. proxy.padding.width (Mind that proxy.x doesn't work. Use proxy.border.x)