diff options
Diffstat (limited to 'lisp/emacs-lisp/cl-macs.el')
| -rw-r--r-- | lisp/emacs-lisp/cl-macs.el | 32 |
1 files changed, 25 insertions, 7 deletions
diff --git a/lisp/emacs-lisp/cl-macs.el b/lisp/emacs-lisp/cl-macs.el index 9af014cf8e9..43eb4261162 100644 --- a/lisp/emacs-lisp/cl-macs.el +++ b/lisp/emacs-lisp/cl-macs.el @@ -892,7 +892,7 @@ This is compatible with Common Lisp, but note that `defun' and (defvar cl--loop-name) (defvar cl--loop-result) (defvar cl--loop-result-explicit) (defvar cl--loop-result-var) (defvar cl--loop-steps) -(defvar cl--loop-symbol-macs) +(defvar cl--loop-symbol-macs) (defvar cl--loop-guard-cond) (defun cl--loop-set-iterator-function (kind iterator) (if cl--loop-iterator-function @@ -961,7 +961,7 @@ For more details, see Info node `(cl)Loop Facility'. (cl--loop-accum-var nil) (cl--loop-accum-vars nil) (cl--loop-initially nil) (cl--loop-finally nil) (cl--loop-iterator-function nil) (cl--loop-first-flag nil) - (cl--loop-symbol-macs nil)) + (cl--loop-symbol-macs nil) (cl--loop-guard-cond nil)) ;; Here is more or less how those dynbind vars are used after looping ;; over cl--parse-loop-clause: ;; @@ -996,7 +996,24 @@ For more details, see Info node `(cl)Loop Facility'. (list (or cl--loop-result-explicit cl--loop-result)))) (ands (cl--loop-build-ands (nreverse cl--loop-body))) - (while-body (nconc (cadr ands) (nreverse cl--loop-steps))) + (while-body + (nconc + (cadr ands) + (if (or (not cl--loop-guard-cond) (not cl--loop-first-flag)) + (nreverse cl--loop-steps) + ;; Right after update the loop variable ensure that the loop + ;; condition, i.e. (car ands), is still satisfied; otherwise, + ;; set `cl--loop-first-flag' nil and skip the remaining + ;; body forms (#Bug#29799). + ;; + ;; (last cl--loop-steps) updates the loop var + ;; (car (butlast cl--loop-steps)) sets `cl--loop-first-flag' nil + ;; (nreverse (cdr (butlast cl--loop-steps))) are the + ;; remaining body forms. + (append (last cl--loop-steps) + `((and ,(car ands) + ,@(nreverse (cdr (butlast cl--loop-steps))))) + `(,(car (butlast cl--loop-steps))))))) (body (append (nreverse cl--loop-initially) (list (if cl--loop-iterator-function @@ -1506,10 +1523,11 @@ For more details, see Info node `(cl)Loop Facility'. ,(cl--loop-let (nreverse loop-for-sets) 'setq ands) t) cl--loop-body)) - (if loop-for-steps - (push (cons (if ands 'cl-psetq 'setq) - (apply 'append (nreverse loop-for-steps))) - cl--loop-steps)))) + (when loop-for-steps + (setq cl--loop-guard-cond t) + (push (cons (if ands 'cl-psetq 'setq) + (apply 'append (nreverse loop-for-steps))) + cl--loop-steps)))) ((eq word 'repeat) (let ((temp (make-symbol "--cl-var--"))) |