"rednet.send" problems; sending nil

Lupus590, on 23 October 2016 - 10:35 PM said:

ServerStartup.lua line 2: checkForModem_modem is not defined yet, move function above the one which calls it. Additionally, that is not how to call a function if you are trying to send a function over rednet then you can't due to limitations of our current Lua version.

RCDStartup.lua line 2: same issue as above

This issue seems to be throughout your code, you need to tell the computer what something is before you tell it to use it. I'm interested in how you managed to get this to even run.

alpha = 1
beta = 2
rednet.open(side)
rednet.send(beta, "do_something")

rednet.open(side)
id, message = rednet.receive(10)
if message == "do_something" then
something()
end

Lupus590, on 23 October 2016 - 10:35 PM said:

This issue seems to be throughout your code, you need to tell the computer what something is before you tell it to use it. I'm interested in how you managed to get this to even run.

        if not senderID_A or id == senderID_A then
            local senderID_A = id
            local senderUSER_A = username
        elseif not senderID_B or id == senderID_B then
            local senderID_B = id
            local senderUSER_B = username
        elseif not senderID_C or id == senderID_C then
            local senderID_C = id
            local senderUSER_C = username
        elseif not senderID_D or id == senderID_D then
            local senderID_D = id
            local senderUSER_D = username
        elseif not senderID_E or id == senderID_E then
            local senderID_E = id
            local senderUSER_E = username
        else
            printMessage(1, "Cannot store anymore IDs")
            return false
        end

Bomb Bloke, on 24 October 2016 - 02:24 AM said:

Spoiler

Lupus590, on 23 October 2016 - 10:35 PM said:

This issue seems to be throughout your code, you need to tell the computer what something is before you tell it to use it. I'm interested in how you managed to get this to even run.

That bit works because checkForModem_modem is defined within the global scope by checkForModem(), which is called before setHost().

Granted, everything would ideally be localised, but that particular bit won't error. It'd also be a heck of a lot easier to read if not for the redundant functions everywhere… it's less "simple" and more "reading a choose-your-own-adventure novel with only one paragraph on each page". :|

(When writing a function, ask yourself - am I going to call this from more than one place in the script? If the answer's no, then reconsider what you're doing - don't use function definitions as if they were comments!)

Speaking of which, keep in mind that whenever you perform a function call, Lua puts a new running instance of that function onto the function stack. That then stays there until your function returns, at which point the next function down continues from where it left off.

This means that if you create a loop of recursive function calls, such as the one you've constructed between the logIn() and logIn_retry() functions within RCDStartup.lua, there's a potential crash bug when Lua eventually runs out of the memory reserved for such shenanigans and you get a stack overflow. If you want to perform a loop, use while/repeat/for.

Remember that if you make a variable local to a given block it'll effectively be discarded from memory as soon as that block ends. For example, no matter how this lot resolves:

Spoiler

		if not senderID_A or id == senderID_A then
			local senderID_A = id
			local senderUSER_A = username
		elseif not senderID_B or id == senderID_B then
			local senderID_B = id
			local senderUSER_B = username
		elseif not senderID_C or id == senderID_C then
			local senderID_C = id
			local senderUSER_C = username
		elseif not senderID_D or id == senderID_D then
			local senderID_D = id
			local senderUSER_D = username
		elseif not senderID_E or id == senderID_E then
			local senderID_E = id
			local senderUSER_E = username
		else
			printMessage(1, "Cannot store anymore IDs")
			return false
		end

… senderID_A / senderUSER_A / senderID_B / etc will all be nil at the end of it, because you localised them to those tiny little "if" blocks. You'd be better off defining them above as upvalues, or better again, sticking them all into the one table (which you could then iterate through instead of repeating your code).

http://lua-users.org...i/ScopeTutorial

Anyway, line 203 in RCDStartup.lua - did you not mean to print "reply"?