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confusing with the global variable in plugin

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Posted by

Yeedoo China (12 posts) Bio

Date

Sun 19 Feb 2012 02:29 AM (UTC)

Message

First,I am a newbie, not only for mushclient but also for lua
I tried to visit a _G var created by my script from a plugin. but failed
Then i tried to create a global variable from a plugin
such as in the function OnPluginInstall
but when i print the _G table in mushclient, i couldnt find the var that i created in plugin
by the way, the mushclient vision is 4.81
How to fix that? Any advice will be appreciated, Thank you!

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Posted by

Twisol USA (2,257 posts) Bio

Date

Reply #1 on Sun 19 Feb 2012 03:36 AM (UTC)

Message

Can you post your code please? If it's too large, feel free to dump it at pastebin.com and give us the link. Without seeing the code, any number of things could be happening.

'Soludra' on Achaea

Blog: http://jonathan.com/
GitHub: http://github.com/Twisol

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Posted by

Nick Gammon Australia (23,120 posts) Bio Forum Administrator

Date

Reply #2 on Mon 20 Feb 2012 01:34 AM (UTC)

Message

Plugins and the "main" world share different script spaces.

- Nick Gammon

www.gammon.com.au, www.mushclient.com

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Posted by

Yeedoo China (12 posts) Bio

Date

Reply #3 on Tue 21 Feb 2012 05:03 AM (UTC)

Message

Resolved
I tried to visit a global table that was not initialized correctly.
Thank you ,all of you

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Posted by Wahnsinn USA (8 posts) Bio

Date Reply #4 on Tue 28 Feb 2012 01:24 PM (UTC)

Message

I'm having a rough time with an attempt at a global variable in a plugin as well. Trying to follow the various instructions in the forum closely, I'm using this:


<![CDATA[
require "serialize"

ch = {}

-- Some functions that assign values to ch items
-- In desperation I even added
SetVariable ("ch", "ch = " .. serialize.save_simple (ch))
-- to one that I knew was setting values to ensure that SetVariable was being called

-- -----------------------------------------------------------------
--  Built-in callbacks
-- -----------------------------------------------------------------
function OnPluginInstall ()
	assert (loadstring (GetVariable ("ch") or "")) ()
	if ch.HP == nil then
		ColourNote ("red", "", "Initializing ch")
		ch = {
			name = "Unknown",
			race = "Unknown",
			class = "Unknown",
			hasMagic = false,
			isFighting = false,
			align = "Neutral",
			HP = { cur = 0, total = 100, },
			MA = { cur = 0, total = 0, },
			stats = { STR = 1, AGI = 1, INT = 1, HEA = 1, WIS = 1, CHA = 1, }
		}
	else
		ColourNote ("yellow", "", "Loading " .. ch.name)
	end
end
function OnPluginSaveState ()
	SetVariable ("ch", "ch = " .. serialize.save_simple (ch))
end

Yet every time I load the world I see the red message that the ch variable is being initialized. Can someone educate me on where I'm going wrong?

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Posted by Nick Gammon Australia (23,120 posts) Bio Forum Administrator

Date Reply #5 on Tue 28 Feb 2012 06:54 PM (UTC)

Message

This works for me:


<muclient>
<plugin
   name="test_variables"
   author="Nick Gammon"
   id="d391d2f095192d2d48f9870e"
   language="Lua"
   purpose="testing initializing variables"
   save_state="y"
   date_written="2012-02-28 18:12:26"
   requires="4.81"
   version="1.0"
   >

</plugin>


<!--  Script  -->


<script>
<![CDATA[
require "serialize"

ch = {}

-- -----------------------------------------------------------------
--  Built-in callbacks
-- -----------------------------------------------------------------
function OnPluginInstall ()
	assert (loadstring (GetVariable ("ch") or "")) ()
	if ch.HP == nil then
		ColourNote ("red", "", "Initializing ch")
		ch = {
			name = "Unknown",
			race = "Unknown",
			class = "Unknown",
			hasMagic = false,
			isFighting = false,
			align = "Neutral",
			HP = { cur = 0, total = 100, },
			MA = { cur = 0, total = 0, },
			stats = { STR = 1, AGI = 1, INT = 1, HEA = 1, WIS = 1, CHA = 1, }
		}
	else
		ColourNote ("yellow", "", "Loading " .. ch.name)
	end
end

function OnPluginSaveState ()
	SetVariable ("ch", "ch = " .. serialize.save_simple (ch))
end

]]>
</script>

</muclient>

I only see the initializing message the first time. Make sure you have "save_state" set to y (line in bold) or it won't work.

This isn't a global variable by the way, it is a plugin variable saved in the plugin state file.

- Nick Gammon

www.gammon.com.au, www.mushclient.com

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Posted by

Wahnsinn USA (8 posts) Bio

Date

Reply #6 on Wed 29 Feb 2012 02:49 AM (UTC)

Message

Thanks so much Nick, you nailed it. Once I added save_state to the plugin it finally started working as expected.

The docs say that creating a variable without "local" make it global, or is that in reference to some scripting location other than a plugin? What would be the proper way to expose my ch variable here so that it can be read and written by other plugins?

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Posted by

Nick Gammon Australia (23,120 posts) Bio Forum Administrator

Date

Reply #7 on Wed 29 Feb 2012 03:22 AM (UTC)

Message

Global just means it is in the "global environment" table (effectively, a global variable) as opposed to being local to the current block.

It is nothing to do with whether or not the variable is shared between plugins. Each plugin has its own script space (and hence its own variables), by design.

- Nick Gammon

www.gammon.com.au, www.mushclient.com

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Posted by

Wahnsinn USA (8 posts) Bio

Date

Reply #8 on Wed 29 Feb 2012 03:39 AM (UTC)

Message

Excellent, I appreciate the clarification, thank you. I'm really enjoying working with MUSHclient and Lua, and the fact that you reply so promptly in the forums and with such helpful information is just... priceless. Great work!

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