Global variables

[jacosro]

Static attributes of each class are represented as global variables. This means that each method declaration will have a global_formal_in and global_formal_out parameter for each one of the global variables of the program (static attributes of every class). Consequently, every method call will also have global_actual_in and global_actual_out nodes for each global variable.

Four new NodeTypes must be added: GLOBAL_FORMAL_IN, GLOBAL_FORMAL_OUT, GLOBAL_ACTUAL_IN, GLOBAL_ACTUAL_OUT, in order to be able to distinguish them from normal parameters.

@cargaji What do you think?

[cargaji]

I'm not sure whether new types are needed or not. Types as classes would be useful to unify both formal and actual types, but that can be done after-the-fact. The main difficulty here is locating global variable usage and definitions.

In Java, only static elements can be "global variables", as all others will be accessed via this, a parameter or a static field.

[cargaji]

This issue can be split into static fields (see #46) and class fields (already supported in 1.3.0).