Var = _{Attribute}If Var is a free variable, it will be bound to a new attributed variable whose attribute corresponding to Module will be Attribute. If Var is already an attributed variable and the corresponding attribute is a free variable, it will be bound to Attribute. Otherwise, if the attribute is not a free variable or if Var is instantiated, it will be unified with a new attributed variable whose corresponding attribute is Attribute and all other attributes are free variables.
If Module is an atom, the attribute corresponding to a previous meta_attribute declaration will be used. If Module is an integer, it is directly used as the index slot (this is mainly used by the compiler to resolve attribute references at compile time).
[eclipse 6]: meta_attribute(extra, []). yes. [eclipse 3]: add_attribute(X, a, extra), printf("%QPMw", X). X{suspend : _g270 , extra : a} X = X yes