zl:1 - FTP

601 si :unencapsulate-function-spec
The value returned is the uninterned symbol from inside the last encapsulation
skipped. This uninterned symbol is the flrst one that does not
have a deflnition that is an encapSUlation that should be skipped. Or the
value can be function-spec if function-spec's deflnition is not an encapsulation
that should be skipped.
The types of encapsulations to be skipped over are specilled by
encapSUlation-types. This can be a list of the types to be skipped, or nil,
meaning skip all encapsulations (this is the default). Skipping all encapsulations
means returning the uninterned symbol that holds the basic
deflnition of function-spec. That is, the definition of the function spec
returned is the basic definition of the function spec supplied. Thus:
(fdefinition (si:unencapsulate-function-spec 'faa»
returns the basic definition of foo, and:
(fdefine (si:unencapsulate-function-spec 'faa) 'bar)
sets the basic deimition (just like using fdefine with carefully supplied as
t).
encapSUlation-types can also be a symbol, which should be an encapsulation
type; then we skip all types that are supposed to come outside of the
specilled type. For example, if encapsulation-types is trace, then we skip
all types of encapsulations that come outside of trace encapsulations, but
we do not skip trace encapsulations themselves. The result is a function
spec that is where the trace encapsulation ought to be, if there is one. Either
the definition of this function spec is a trace encapsulation, or there
is no trace encapsulation anywhere in the definition of function-spec, and
this function spec is where it would belong if there were one. For example:
(let «tern (si:unencapsulate-function-spec spec 'trace»)
(and (eq tern (si:unencapsulate-function-spec tern '(trace»)
(si:encapsulate tern spec 'trace '( . .. body .. . »»
flnds the place where a trace encapsulation ought to go, and makes one
unless there is already one there.
(let «tern (si:unencapsulate-function-spec spec 'trace»)
(fdefine tern (fdefinition (si:unencapsulate-function-spec
tern '(trace»»)
eliminates any trace encapSUlation by replacing it by whatever it encapsulates.
(If there is no trace encapSUlation, this code changes nothing.)
These examples show how a subsystem can insert its own type of encapsulation
in the proper sequence without knowing the names of any other
types of encapSUlations. Only the si:encapsulation-standard-order variable,
which is used by si:unencapsulate-function-spec, knows the order.
I