cl: Multiple Values
4.8 Multiple Values
===================
Common Lisp functions can return zero or more results. Emacs Lisp
functions, by contrast, always return exactly one result. This package
makes no attempt to emulate Common Lisp multiple return values; Emacs
versions of Common Lisp functions that return more than one value either
return just the first value (as in ‘cl-compiler-macroexpand’) or return
a list of values. This package _does_ define placeholders for the
Common Lisp functions that work with multiple values, but in Emacs Lisp
these functions simply operate on lists instead. The ‘cl-values’ form,
for example, is a synonym for ‘list’ in Emacs.
-- Macro: cl-multiple-value-bind (var...) values-form forms...
This form evaluates VALUES-FORM, which must return a list of
values. It then binds the VARs to these respective values, as if
by ‘let’, and then executes the body FORMS. If there are more VARs
than values, the extra VARs are bound to ‘nil’. If there are fewer
VARs than values, the excess values are ignored.
-- Macro: cl-multiple-value-setq (var...) form
This form evaluates FORM, which must return a list of values. It
then sets the VARs to these respective values, as if by ‘setq’.
Extra VARs or values are treated the same as in
‘cl-multiple-value-bind’.
Since a perfect emulation is not feasible in Emacs Lisp, this package
opts to keep it as simple and predictable as possible.
Info Catalog
cl: Loop Facility
cl: Control Structure