diff options
Diffstat (limited to 'lisp/emacs-lisp/cl-macs.el')
| -rw-r--r-- | lisp/emacs-lisp/cl-macs.el | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/lisp/emacs-lisp/cl-macs.el b/lisp/emacs-lisp/cl-macs.el index 312c37261e..16ac14f8fe 100644 --- a/lisp/emacs-lisp/cl-macs.el +++ b/lisp/emacs-lisp/cl-macs.el @@ -1463,8 +1463,15 @@ Valid clauses are: cl--loop-accum-var)))) (defun cl--loop-build-ands (clauses) + "Return various representations of (and . CLAUSES). +CLAUSES is a list of Elisp expressions, where clauses of the form +\(progn E1 E2 E3 .. t) are the focus of particular optimizations. +The return value has shape (COND BODY COMBO) +such that COMBO is equivalent to (and . CLAUSES)." (let ((ands nil) (body nil)) + ;; Look through `clauses', trying to optimize (progn ,@A t) (progn ,@B) ,@C + ;; into (progn ,@A ,@B) ,@C. (while clauses (if (and (eq (car-safe (car clauses)) 'progn) (eq (car (last (car clauses))) t)) @@ -1475,6 +1482,7 @@ Valid clauses are: (cl-cdadr clauses) (list (cadr clauses)))) (cddr clauses))) + ;; A final (progn ,@A t) is moved outside of the `and'. (setq body (cdr (butlast (pop clauses))))) (push (pop clauses) ands))) (setq ands (or (nreverse ands) (list t))) |