Global Names

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

(undefine symbol) causes symbol to be undefined in the current namespace if it was defined previously.

(global-defined-value symbol) returns the value of the global variable named by the symbol in the current namespace. If symbol is undefined, the exn:variable exception is raised.

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