Function MAKE-SHARED-ENVIRONMENT
Package:
COMMON-LISP.EXTENSIONS.DATA-AND-CONTROL-FLOW.UNIFICATION
Syntax:
make-shared-environment env => unification-environment
Arguments and Values:
env---an unification-environment.
unification-environment---a new unification-environment.
Description:
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.
Affected By:
None.
Exceptional Situations:
None.
See Also:
UNIFY:ENVIRONMENT, BINDING, FIND-VARIABLE-VALUE
Notes:
This function is provided to allow for the construction of "trees" of frames for interpreter-like environments. The macros MATCH, MATCHING, 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.
The use of MAKE-SHARED-ENVIRONMENT in MATCHING and MATDCH-CASE is still incomplete.