Nested environments

Environments can be nested, in which case the binding in the innermost environment hides those in outer environments. This means that a stack can be used to store the Environment values:

Instantiate a stack module for environment values[48]:

$/Adt/Stack.gnrc +instance=Region +referto=Environment :inst

This macro is invoked in definition 57.

New region[49]:

RegionStackPush(CurrentEnv); CurrentEnv = NewScope(CurrentEnv);

This macro is invoked in definitions 21 and 54.

End region[50]:

CurrentEnv = RegionStackTop; RegionStackPop;

This macro is invoked in definitions 21 and 54.