LUA script help please. [Solved]

[bobingabout]

Despite the vast evidence that I'm good at LUA, I'm not the best when it comes to knowing LUA script.

I have a GUI object named button#, where # is an unknown number that I Want to find.

First I did this:

Code: Select all

      for i=1,49 do
        if event.element.name == "button" .. i then
--other code here
        end
      end

And although it worked, I thought it was dumb.

so I did this:

Code: Select all

      i = tonumber(string.sub(event.element.name, string.find(event.element.name, "%d+")))
--other code here

And although that works too, there's a function call (find the start and end bytes of the number) in a function call (extract those bytes of data as a string) in a function call (convert that string to a number)... I don't like it either.



Does anyone have any ideas for a better way of doing it?

[Klonan]

so I did this:

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      i = tonumber(string.sub(event.element.name, string.find(event.element.name, "%d+")))
--other code here

And although that works too, there's a function call (find the start and end bytes of the number) in a function call (extract those bytes of data as a string) in a function call (convert that string to a number)... I don't like it either.

Does anyone have any ideas for a better way of doing it?

You can simplify this a little but, but personally i don't mind the iterating method

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local string = event.element.name
local i = string:gsub("button", "")
--other code here

The 'tonumber' isn't strictly necessary, as if you do anything with it, it will be interpreted correctly as a number - even though type() says it is a string

[bobingabout]

The 'tonumber' isn't strictly necessary, as if you do anything with it, it will be interpreted correctly as a number - even though type() says it is a string

In my case it is required, because the number is used as an index in a table. If I use the string directly, it returns nil, but if I tonumber it first, it returns the value.
I did actually try this without the tonumber, that's why I know it doesn't work without it.

Thanks for your advice.

new code:

Code: Select all

      local string = event.element.name
      local s = string:gsub("button", "")
      local i = tonumber(s)
-- other code here

It does look better, I'll change it and try it now.

[Klonan]

The 'tonumber' isn't strictly necessary, as if you do anything with it, it will be interpreted correctly as a number - even though type() says it is a string

In my case it is required, because the number is used as an index in a table. If I use the string directly, it returns nil, but if I tonumber it first, it returns the value.
I did actually try this without the tonumber, that's why I know it doesn't work without it.

Thanks for your advice.

While i'm not sure which is more efficient, you can just add 0 to the result, instead of calling tonumber()

In the end it will make practically no difference

[Choumiko]

Code: Select all

i = tonumber(string.match(event.element.name, "%d+$"))

This should take only numbers from the end of the string, just in case at some point you want something like 1button2

[bobingabout]

Code: Select all

i = tonumber(string.match(event.element.name, "%d+$"))

This should take only numbers from the end of the string, just in case at some point you want something like 1button2

Good advice, and although it does work, for some reason I decided to use Klonan's solution. Maybe it's the intimidating face in his huge avatar, or perhaps the pink name.

Okay, after a little tinkering, I've decided on the following.

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      local i = string.gsub(event.element.name, "button", "") + 0
--other code here

Thanks for the help guys.

[Mooncat]

One thing to note: if you want to use on_gui_click, which is very likely you would, you may need to consider adding prefix to your button names.

Having generic names like "button0" is not safe. If there is another mod using the same button name, clicking its button will also trigger on_gui_click with the same name on your mod.
That's why I added "creative-mode_" prefix in all my GUI elements, as well as items, entities, etc.

But if you use hyphen (-), you will need to escape it with % when used as pattern in string.sub, string.gsub, string.find, string.match, etc. i.e. it will be "creative%-mode_"

[bobingabout]

One thing to note: if you want to use on_gui_click, which is very likely you would, you may need to consider adding prefix to your button names.

Having generic names like "button0" is not safe. If there is another mod using the same button name, clicking its button will also trigger on_gui_click with the same name on your mod.
That's why I added "creative-mode_" prefix in all my GUI elements, as well as items, entities, etc.

But if you use hyphen (-), you will need to escape it with % when used as pattern in string.sub, string.gsub, string.find, string.match, etc. i.e. it will be "creative%-mode_"

I have already thought of this. I actually have 3 sets of buttons, two named button1 to button49, and one of only 1 to 9. The clicked check is in two phases, first to check the name of the button that was pressed, to see if it starts with "button", and the second check checks the name of the parent. Although the button itself doesn't have a prefix, the parent does.

So... you have actually given me something to think about here, perhaps I should prefix those buttons too, with something like "bob_inserters_"
Note, I use underscores not dashes, so I can actually reference it such as gui.bob_inserters_pickup.button1.state if I want to. Works with underscores, not with dashes.

[Mooncat]

One thing to note: if you want to use on_gui_click, which is very likely you would, you may need to consider adding prefix to your button names.

Having generic names like "button0" is not safe. If there is another mod using the same button name, clicking its button will also trigger on_gui_click with the same name on your mod.
That's why I added "creative-mode_" prefix in all my GUI elements, as well as items, entities, etc.

But if you use hyphen (-), you will need to escape it with % when used as pattern in string.sub, string.gsub, string.find, string.match, etc. i.e. it will be "creative%-mode_"

I have already thought of this. I actually have 3 sets of buttons, two named button1 to button49, and one of only 1 to 9. The clicked check is in two phases, first to check the name of the button that was pressed, to see if it starts with "button", and the second check checks the name of the parent. Although the button itself doesn't have a prefix, the parent does.

So... you have actually given me something to think about here, perhaps I should prefix those buttons too, with something like "bob_inserters_"
Note, I use underscores not dashes, so I can actually reference it such as gui.bob_inserters_pickup.button1.state if I want to. Works with underscores, not with dashes.

Yes, checking on parent element first works too! In fact, I also do it in my mod.
Because I think using string patterns is slower than straightforward string comparison. Not tested though.
(But I believe the difference is negligible. It is on-click event, it isn't supposed to run very frequently anyway. Just a (bad) habit. )

But keeping the child button name to be generic may still cause problems if someone thought on_gui_click is only called for the elements from his mod so "button0" always refer to his button, and he does something like

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if button.name == "button0" then
  button.destroy()
end

Just play safe.