Global Names

(defined? name), where name is a symbol, returns #t if a global variable is defined with the name name in the current namespace, #f otherwise.

(undefine name), where name is a symbol, causes name to be undefined in the current namespace if it was defined previously.

(global-defined-value name) returns the value of the global variable named by the symbol name in the current namespace. If name is undefined, the exn:variable exception is raised. (global-defined-value name v) sets the value of name in the current namespace (defining name if it is not already defined).

(make-global-value-list) returns an association list that pairs each globally-defined symbol with its current value from the current namespace.

(built-in-name name) determines whether name is a built-in variable. If the symbol name can be used within a unit as a built-in variable, then built-in-name returns a keyword-form variable that accesses the built-in binding. Otherwise, #f is returned. See also section 4.10.2.