LÖVE

Posted: **Tue Nov 21, 2017 10:50 am**

so i wanna make a function to generate polygon with color, it looks like this

function poly(... , color)
local edges = {...}
local color = color
end

even when i dont run the function, i got an error already, how can i achieve this ?

Posted: **Tue Nov 21, 2017 11:09 am**

The problem is that you can only have varargs as the last argument(s). So if you rewrite your function like this, it won't error:

Code: Select all

function poly(color, ...)
    local edges = {...}
end

(Note that color is already a local, as it is an argument, so 'local color = color' doesn't actually do anything useful.)

Posted: **Tue Nov 21, 2017 11:20 am**

bartbes wrote: ↑Tue Nov 21, 2017 11:09 am The problem is that you can only have varargs as the last argument(s). So if you rewrite your function like this, it won't error:
Code: Select all
function poly(color, ...)
    local edges = {...}
end
(Note that color is already a local, as it is an argument, so 'local color = color' doesn't actually do anything useful.)

alright, but how do i check if the color is not nil ? using color ~= nil return an error

Posted: **Tue Nov 21, 2017 11:33 am**

So you're saying you should be able to pass edges to the function while not passing a color, correct?

Is the "color" that you're passing a table that looks something like this? {255, 0, 0}. If that's what a "color" is then you could try this...

Code: Select all

function poly(color, ...)
    local args = {...}
    local edges = {}

    if type(color) ~= "table" then
        edges[1] = color
    end
    
    for i = 1, #args do
        table.insert(edges, args[i]) 
    end
end

Posted: **Tue Nov 21, 2017 11:44 am**

I'd also be interested in where you got a error with color ~= nil, since that should work under most circumstances.

Code: Select all

local color =                          color or {255,255,255,255}
----
local color =      color  ~=  nil  and color or {255,255,255,255}
----
local color = type(color) ~= 'nil' and color or {255,255,255,255}
----
-- And the same 3 ways can be used with if-then-else, as well.

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