make-shared-environment env => unification-environment
Arguments and Values:
unification-environment---a new unification-environment.
The function MAKE-SHARED-ENVIRONMENT constructs a new object of type UNIFY:ENVIRONMENT. The new unification-environment shares the frames already present in env.
It is guaranteed that extending unification-environment will not change env.
UNIFY:ENVIRONMENT, BINDING, FIND-VARIABLE-VALUE
This function is provided to allow for the construction of "trees" of frames for interpreter-like environments. The macros MATCH, MATCHF, MATCHING, MATCHF-CASE and MATCH-CASE rely on this function, as they immediately construct a "shared" environment.
Current Implementation Note
MAKE-SHARED-ENVIRONMENT relies on the LIST implementation of environments.