The following functions are available to build one’s own interpreter functions that use the
built-in Fluid binding mechanism, and interact well with the automatic unbinding that takes
place during Throw and Error calls.
(unbindn N:integer): Undefined expr
Used in user-defined interpreter functions (like prog) to restore previous
bindings to the last N values bound.
(lbind1 IDname:id VALUETOBIND:any): Undefined expr
Support for lambda-like binding. The current value of IDname is saved on
the binding stack; the value of VALUETOBIND is then bound to IDname.
(pbind1 IDname:id): Undefined expr
Support for prog. Binds nil to IDname after saving value on the binding
stack. Essentially (lbind1 IDname nil).
