How to Center text without using tables?

Hello, I have a question:

How do you center text without using tables?

What I usually do is

local w,h = term.getSize()
local titleY = 1
term.clear()
local function center(text, line)
  term.setCursorPos(math.floor(w/2)-string.len(text)/2, line)
  print(text)
end
local title ={ " [ SelectGUI Alpha ] " }
for i,v in ipairs (title) do
	center(v,titleY+i)
end

Pastebin link:

Spoiler

http://pastebin.com/srKsUjd8

Also if anyone could help me make my GUI / OS mouse compatiable it would be greatly appreciated

My GUI / OS ( SelectGUI Alpha)

Spoiler

http://pastebin.com/z19FzBbD

Thanks, AnthonyD98

Try something like this:

local function cPrint(string)
 x, _ = term.getSize()
 _, y = term.getCursorPos()
 term.setCursorPos((x-#string)/2,y)
 print(string)
end

Just give it a string like the regular print function.

I'm confused on this though, do I still need?

for i,v in ipairs (title) do
center(v,titleY+i)
end

Ahh! I see now

cPrint("I am a string!")

And it is centered!

AnthonyD98, on 27 January 2013 - 07:16 PM said:

Ahh! I see now

cPrint("I am a string!")

And it is centered!

Yea :D/> I'll try making a simple menu for you. No promises though.

Zoinky, on 27 January 2013 - 07:18 PM said:

AnthonyD98, on 27 January 2013 - 07:16 PM said:

Ahh! I see now

cPrint("I am a string!")

And it is centered!

Yea :D/> I'll try making a simple menu for you. No promises though.

:D/> Thank you Zoinky for your help, +1 for you.

Also thanks for trying to make a simple menu. And I see your in the same country as me! :)/>

EDIT: Just found out I can't have a picture in my signature :o/>

AnthonyD98, on 27 January 2013 - 07:21 PM said:

Also thanks for trying to make a simple menu.

Sorry, couldn't get one of the functionalities to work without making the program really large, so I gave up on it. Forgot to mention that. :S

Zoinky, on 27 January 2013 - 09:00 PM said:

AnthonyD98, on 27 January 2013 - 07:21 PM said:

Also thanks for trying to make a simple menu.

Sorry, couldn't get one of the functionalities to work without making the program really large, so I gave up on it. Forgot to mention that. :S

Its alright, atleast you tried :)/>

Zoinky, on 27 January 2013 - 07:07 PM said:

Try something like this:

local function cPrint(string)
x, _ = term.getSize()
_, y = term.getCursorPos()
term.setCursorPos((x-#string)/2,y)
print(string)
end

Just give it a string like the regular print function.

Also I can add this code to the API I'm making - ( Private API )

Just a note, you shouldn't use string as an argument name, as it means you can't access the string table used for string functions inside that function.
You might not want to use things like string.sub or string.len ( more so when you have #stringvar )

but you should typically avoid it always, it helps when debugging in the future.

local function cPrint(str)
x, _ = term.getSize()
_, y = term.getCursorPos()
term.setCursorPos((x-#str)/2,y)
print(str)
end

^ That would serve you better as a reference.

NeverCast, on 28 January 2013 - 12:03 PM said:

Just a note, you shouldn't use string as an argument name, as it means you can't access the string table used for string functions inside that function.
You might not want to use things like string.sub or string.len ( more so when you have #stringvar )

I said this once too when someone did the same thing and then someone else pointed out to me that it doesn't matter. I tested it then and indeed, if it can't index it in the local scope, it appears to search for a global variable with the same name that it can index (I was quite shocked by it). So it would work, but it's still very bad practice IMO.

it's very bad practice yes, but it does make sense. The local tables metatable indeed has _G in it's __index. So it makes sense that it would do that.
But you shouldn't ever override or hide global tables or functions, unless it's your explicit intention to do so.

You've certainly taught me something, although I understand it, I wouldn't have guessed the outcome.

I didn't know that local variables had _G as __index in their metatables so I learn something as well. :)/> It's perfectly logical now.

not local variables, I meant the environment that the function is running in.. Give me a moment, I'll check it :D/>

local function coolStory(string)
	local string = string
	local env = getfenv()
	local mt = getmetatable(env)
	local callback = mt.__index
	print(callback)
	oldString = callback(env, "string")
	print(string)
	print(oldString)
	string = string.sub(string, 1,2)
	print(string)
end

coolStory("hello")

Showing how it works.
Seems that when it can't find string.bla, it grabs the local environments metatable and does a call on it, to get the string table

Edit: ONLY works because the argument is a string, if you make it a table, it does NOT work!

Edit2: After more thinking I think it's the way that Lua determines what variable to compile against.
When it determines that you are looking for a table ( string.bla) then it looks for the local table by that name, if it's not available, it looks for the next upvalue with that name. So it searches for variables by type.

How it works entirely I can't be certain, But I think it's more of Lua compiling and looking for a table instead of just any variable.

NeverCast, on 28 January 2013 - 01:06 PM said:

local function coolStory(string)
	local string = string
	local env = getfenv()
	local mt = getmetatable(env)
	local callback = mt.__index
	print(callback)
	oldString = callback(env, "string")
	print(string)
	print(oldString)
	string = string.sub(string, 1,2)
	print(string)
end

coolStory("hello")

Showing how it works.
Seems that when it can't find string.bla, it grabs the local environments metatable and does a call on it, to get the string table

Edit: ONLY works because the argument is a string, if you make it a table, it does NOT work!

I kinda assumed it was the function environment but I paraphrased you wrongly. :P/> It's what I thought.

It's probably a combination of using the __index + looking for a table.
Not sure. One way to find out would be to change the index to a table with a different string table in it.

Guys, getting a little off-topic-ish*. Lol. :D/>

* Don't hurt me D:

AnthonyD98, on 28 January 2013 - 10:54 AM said:

Zoinky, on 27 January 2013 - 07:07 PM said:

-snip-

Also I can add this code to the API I'm making - ( Private API )

Erm, sure. Go ahead :D/>

Edit: Crap, double post. Is it possible to have a moderator merge them? :3

Just divide the screen width by 2, and do the same with the text length. Then you set the cursor position and write.