(This may be confusing and poorly written. Maybe better than nothing. Maybe not. Ask if you have any questions.)
Parsing
Kerbalua uses ANTLR to parse through code in order to find the context of what it is being asked to find completions for.
It does this using a special grammar that finds the last variable name prior to the cursor position and stores a list of operations that were chained from that variable.
For example, in the following code
native.System.Collections.Generic.
the operation list is
Get(native), Get(System), Get(Collections), Get(Generic), Get()
The first operation is Get(native), and the completion system is going to interpret it as a global variable acceout of the table, and uses it to look up the first operation.
Completion
After the CompletionOperations object has been created, completion is started with the script’s Global variables Table and the first operation.
The Global variables Tables becomes the first CompletionObject.
Get(native) is looked up in the table, and returned to become the new CompletionObject
Then that is searched for Get(System) and so on.
Once it gets to the end, the final Get() represents that the completion system should display all possibilities.
If the final operation was Get(ab) it would only return possiblities containing the string “ab”.