reducing is the act of taking values, two at a time, and combining them, with the aid of a reducing function, into a single final value.
Function MAKE-REDUCER Create a function which, starting with INITIAL-VALUE, reduces any other values into a single final value.
Macro WITH-REDUCER Locally bind NAME to a reducing function.
Building up a list from multiple values.
Function MAKE-COLLECTOR Create a collector function.
Function MAKE-PUSHER Create a function which collects values as by PUSH.
Macro WITH-COLLECTOR Bind NAME to a collector function and execute BODY.
Macro WITH-COLLECTORS Bind multiple collectors.