yes, we could move it up to Association�� but we should keep VariableBinding as a subclass of
Literal so that people in the future e.g. can put a halt on a variable defined in the
workspace.

And yes, in general we need a nice API for the compiler to hand bindings to it�� it is on my TODO
list.

https://pharo.fogbugz.com/f/cases/15490/provide-a-way-to-specify-external-binding-to-the-compiler��

This Slice adds an API to the compiler to set a dictionary with bindings to be taken into account.
They are compiled as pushLinteralVariable: (thus refer to the association of the dictionary)

Smalltalk compiler
��bindings: { #a -> 3 } asDictionary;
��evaluate: '1+a'.

Internally this for now (ab)-uses the #requestor: API... later we will change this to be inverted: the requestors
should privide binding and get notified using Announcements.