0.6.11.28:

[sbcl.git] / src / code / early-extensions.lisp

diff --git a/src/code/early-extensions.lisp b/src/code/early-extensions.lisp
index d8d0d63..0d40d30 100644 (file)
--- a/src/code/early-extensions.lisp
+++ b/src/code/early-extensions.lisp
@@ -391,6 +391,27 @@
                      (format nil "~S" expr)))))
 (defun %failed-aver (expr-as-string)
   (error "~@<failed AVER: ~2I~_~S~:>" expr-as-string))
+
+;;; Return the numeric value of a type bound, i.e. an interval bound
+;;; more or less in the format of bounds in ANSI's type specifiers,
+;;; where a bare numeric value is a closed bound and a list of a
+;;; single numeric value is an open bound.
+;;;
+;;; The "more or less" bit is that the no-bound-at-all case is
+;;; represented by NIL (not by * as in ANSI type specifiers); and in
+;;; this case we return NIL.
+(defun type-bound-number (x)
+  (if (consp x)
+      (destructuring-bind (result) x result)
+      x))
+
+;;; some commonly-occuring CONSTANTLY forms
+(macrolet ((def-constantly-fun (name constant-expr)
+            `(setf (symbol-function ',name)
+                   (constantly ,constant-expr))))
+  (def-constantly-fun constantly-t t)
+  (def-constantly-fun constantly-nil nil)
+  (def-constantly-fun constantly-0 0))
 \f
 ;;;; utilities for two-VALUES predicates