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3.8.27 locally [Special Operator]

locally {declaration}* {form}* => {result}*

Arguments and Values::

Declaration—a declare expression; not evaluated.

forms—an implicit progn.

results—the values of the forms.

Description::

Sequentially evaluates a body of forms in a lexical environment where the given declarations have effect.

Examples::
      (defun sample-function (y)  ;this y is regarded as special
        (declare (special y))
        (let ((y t))              ;this y is regarded as lexical
          (list y
                (locally (declare (special y))
                  ;; this next y is regarded as special
                  y))))
     =>  SAMPLE-FUNCTION
      (sample-function nil) =>  (T NIL)
      (setq x '(1 2 3) y '(4 . 5)) =>  (4 . 5)
     
     ;;; The following declarations are not notably useful in specific.
     ;;; They just offer a sample of valid declaration syntax using LOCALLY.
      (locally (declare (inline floor) (notinline car cdr))
               (declare (optimize space))
         (floor (car x) (cdr y))) =>  0, 1
     ;;; This example shows a definition of a function that has a particular set
     ;;; of OPTIMIZE settings made locally to that definition.
      (locally (declare (optimize (safety 3) (space 3) (speed 0)))
        (defun frob (w x y &optional (z (foo x y)))
          (mumble x y z w)))
     =>  FROB
     
     ;;; This is like the previous example, except that the optimize settings
     ;;; remain in effect for subsequent definitions in the same compilation unit.
      (declaim (optimize (safety 3) (space 3) (speed 0)))
      (defun frob (w x y &optional (z (foo x y)))
        (mumble x y z w))
     =>  FROB
See Also::

declare

Notes::

The special declaration may be used with locally to affect references to, rather than bindings of, variables.

If a locally form is a top level form, the body forms are also processed as top level forms. See File Compilation.