What is this global("foo") function?

[dopezt]

I've just started diving into the code of Don't Stave and I'm trying to familiarize myself before I begin doing anything. I've never done any lua coding before so I'm learning as I go.

 

I've tried googling what this global("foo") is to no avail. I've also tried looking through the don't starve code base and can't find where this is declared.

 

Any sort of help would be welcome. Thanks!

[ZupaleX]

Could you be more precise on your question because I have no idea what you are actually asking

[Arkathorn]

This question is concerning Don't Starve Together, not Don't Starve. The correct forum can be found here.

 

In regards to your question:

I don't know specifically what 'foo' is used for, but the 'global' function declares global variables. Normally in Lua global variables can be declared by assignment, but in Don't Starve the global table has been modified to require this function to be called first. In DST, this likely declares it only for the local instance, not for other networked instances.

[ZupaleX]

I don't understand why you concluded it's for DST. There is the use of global() function in DS codes as well.

[Arkathorn]

1. The string "foo" does not occur anywhere in the DS code, nor in either of the DLCs.

I remember seeing, during my brief foray into the DST code, the statement he is referring to.

[ZupaleX]

foo doesn't appear anywhere as a matter of fact, not even in DST. Thus my first post.

This is usually used in the tutorial or explanations as a placeholder (like the first element will be called "foo" and the second "bar")...

[dopezt]

This question is concerning Don't Starve Together, not Don't Starve. The correct forum can be found here.

 

In regards to your question:

I don't know specifically what 'foo' is used for, but the 'global' function declares global variables. Normally in Lua global variables can be declared by assignment, but in Don't Starve the global table has been modified to require this function to be called first. In DST, this likely declares it only for the local instance, not for other networked instances.

 

foo is actually just a placeholder name. Do you know where specifically in the code this global("") function is defined? I couldn't find it anywhere.

[dopezt]

Could you be more precise on your question because I have no idea what you are actually asking

 

There are calls to global("foo") throughout the code and I want to know what it does. Or actually better I want to know where it is defined if you have any idea.

[ZupaleX]

Why is it so important to know where the global() function is defined? What do you want to do with it? (otherwise it's in strict.lua but it won't help you at all).

 

About what it does, basically what Arkathorn said.

[dopezt]

Why is it so important to know where the global() function is defined? What do you want to do with it? (otherwise it's in strict.lua but it won't help you at all).

 

About what it does, basically what Arkathorn said.

 

This is actually my first time working with lua so I want to learn as much as I can. I especially want to learn the framework because that seems particularly interesting. Thanks!

[Arkathorn]

This is actually my first time working with lua so I want to learn as much as I can. I especially want to learn the framework because that seems particularly interesting. Thanks!

The way the system with the 'global' function works is by overriding the '__index' function of the metatable of the global table.

 

The global table is the generic overarching table, where non-local fields are declared. In 'modmain.lua' and 'modworldgenmain.lua' it is referenced with 'GLOBAL' (due to those files being run in a special environment, achieved with 'setfenv').

 

Metatables are special tables that can be used to add special functionality to other tables. 'getmetatable(t)' returns the metatable of 't' (if any), and 'setmetatable(t,mt)' sets 'mt' as the metatable of 't'.

 

The most common (as far as I can tell) use of metatables is the '__index' function. When a nil field is referenced in a table, it will call it's metatable's '__index' function, if there is one (The first argument is the table, the second the key value). The return value of the function will be returned to the accessor.

 

The '__index' function can be bypassed by using 'rawget(t,k)'.