[fasmg] dot notation use cases...

I don't know if you'd prefer just the basic use cases or even an exotic ones. I'll try to start with just a simple ones.

The basic idea is simple - a dot means that the symbol that follows is in the namespace of the "parent" symbol that preceded the dot:

Code:

A = 'A'
A.a = 'A.a'
A.a.a = 'A.a.a'

namespace A
        display a, 13,10                ; A.a
        display a.a , 13,10             ; A.a.a
        namespace a
                display a, 13,10        ; A.a.a
                display A, 13,10        ; A
        end namespace
end namespace

With NAMESPACE directive we can "enter" any given namespace and this changes the scope. Symbol that was defined as "A.a" outside, inside the "A" namespace can be accessed with just "a". Note that symbols from the outer namespaces can still be accessed simply by name, as long as there is no local symbol that would "overshadow" the global one:

Code:

B = 'B'
B.B = 'B.B'
B.B.b = 'B.B.b'

namespace B
        display B, 13,10                ; B.B
        namespace B
                display B, 13,10        ; B.B (because there is no B.B.B)
                display b, 13,10        ; B.B.b
        end namespace
end namespace

When a symbol starts with a dot, it lies in the namespace of a label in the current namespace that was the most recently defined:

Code:

C:
.a = 'C.a'

namespace C
        display a, 13,10                ; C.a
end namespace

D:
D.a:
.b = 'D.b'

display D.b, 13,10                      ; D.b

Note that the label "D.a" is a symbol named "a" in the "D" namespace. Therefore it does not change what label is the most recent one in the current (outermost) namespace, it is still "D".