Mercurial > hg > xemacs-beta
diff lisp/cl-macs.el @ 5570:6c76f5b7e2e3
Be more careful still in #'cl-defsubst-expand.
lisp/ChangeLog addition:
2011-09-11 Aidan Kehoe <kehoea@parhasard.net>
* cl-macs.el (cl-defsubst-expand):
Be more careful still here, make sure that any references to
variables in BODY don't access those values in the enclosing scope
when that would be inappropriate.
Add some documentation of a potential reasonable approach to
avoiding the problems with our (non-Common Lisp-conformant)
#'symbol-macrolet.
| author | Aidan Kehoe <kehoea@parhasard.net> |
|---|---|
| date | Sun, 11 Sep 2011 16:05:05 +0100 |
| parents | d19b6e3bdf91 |
| children | d4f334808463 |
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line diff
--- a/lisp/cl-macs.el Sat Sep 10 13:17:29 2011 +0100 +++ b/lisp/cl-macs.el Sun Sep 11 16:05:05 2011 +0100 @@ -3238,18 +3238,25 @@ (if (or simple (cl-const-expr-p argv)) (progn ;; Avoid infinite loop on symbol macro - ;; expansion, make sure none of the argvs - ;; refer to the symbols in the argns. + ;; expansion: (or (block find - ;; Can't use cl-expr-contains, that - ;; doesn't descend lambdas: - (subst nil argn argvs :test - #'(lambda (elt tree) + (subst nil argn argvs :test + #'(lambda (elt tree) + ;; Give nil if argn is + ;; in argvs somewhere: (if (eq elt tree) - (return-from find t)))) - nil) - (push (list argn argv) symbol-macros)) - (and unsafe (list (list argn argv)))) + (return-from find))))) + (let ((copy-symbol (copy-symbol argn))) + ;; Rename ARGN within BODY so it + ;; doesn't conflict with its value + ;; in the including scope: + (setq body + (cl-macroexpand-all + body `((,(eq-hash argn) + ,copy-symbol))) + argn copy-symbol))) + (push (list argn argv) symbol-macros) + (and unsafe (list (list argn argv)))) (list (list argn argv)))) argns argvs))) `(let ,lets @@ -3260,6 +3267,13 @@ ;; bound). We don't have GNU's issue where the replacement will ;; be done when the symbol is used in a function context, ;; because we're using #'symbol-macrolet instead of #'subst. + ;; + ;; #'symbol-macrolet as specified by Common Lisp is shadowed by + ;; #'let, #'let* and lambda argument lists, and that would suit + ;; our purposes here perfectly; we could implement it in + ;; cl-macroexpand-all by shadowing any existing symbol macros + ;; when we descend let forms or arglist lambdas. Doing it + ;; unconditionally could well break #'loop, though. ,symbol-macros ,body)))))