(repl noprint)
(critically-unreachable "after REPL")))))))
+;;; Our default REPL prompt is the minimal traditional one.
+(defun repl-prompt-fun (stream)
+ (fresh-line stream)
+ (write-string "* " stream)) ; arbitrary but customary REPL prompt
+
+;;; Our default form reader does relatively little magic, but does
+;;; handle the Unix-style EOF-is-end-of-process convention.
+(defun repl-read-form-fun (in out)
+ (declare (type stream in out) (ignore out))
+ (let* ((eof-marker (cons nil nil))
+ (form (read in nil eof-marker)))
+ (if (eq form eof-marker)
+ (quit)
+ form)))
+
+;;; hooks to support customized toplevels like ACL-style toplevel
+;;; from KMR on sbcl-devel 2002-12-21
+(defvar *repl-read-form-fun* #'repl-read-form-fun
+ "a function of two stream arguments IN and OUT for the toplevel REPL to
+ call: Return the next Lisp form to evaluate (possibly handling other
+ magic -- like ACL-style keyword commands -- which precede the next
+ Lisp form). The OUT stream is there to support magic which requires
+ issuing new prompts.")
+(defvar *repl-prompt-fun* #'repl-prompt-fun
+ "a function of one argument STREAM for the toplevel REPL to call: Prompt
+ the user for input.")
+
(defun repl (noprint)
(/show0 "entering REPL")
(let ((eof-marker (cons :eof nil)))
(loop
- ;; see comment preceding definition of SCRUB-CONTROL-STACK
+ ;; (See comment preceding the definition of SCRUB-CONTROL-STACK.)
(scrub-control-stack)
(unless noprint
- (fresh-line)
- (write-string "* ") ; arbitrary but customary REPL prompt
- (flush-standard-output-streams))
- (let ((form (read *standard-input* nil eof-marker)))
- (cond ((eq form eof-marker)
- (/show0 "doing QUIT for EOF in REPL")
- (quit))
- (t
- (let ((results (multiple-value-list (interactive-eval form))))
- (unless noprint
- (dolist (result results)
- (fresh-line)
- (prin1 result))))))))))
+ (funcall *repl-prompt-fun* *standard-output*)
+ ;; (Should *REPL-PROMPT-FUN* be responsible for doing its own
+ ;; FORCE-OUTPUT? I can't imagine a valid reason for it not to
+ ;; be done here, so leaving it up to *REPL-PROMPT-FUN* seems
+ ;; odd. But maybe there *is* a valid reason in some
+ ;; circumstances? perhaps some deadlock issue when being driven
+ ;; by another process or something...)
+ (force-output *standard-output*))
+ (let* ((form (funcall *repl-read-form-fun*
+ *standard-input*
+ *standard-output*))
+ (results (multiple-value-list (interactive-eval form))))
+ (unless noprint
+ (dolist (result results)
+ (fresh-line)
+ (prin1 result)))))))
;;; suitable value for *DEBUGGER-HOOK* for a noninteractive Unix-y program
(defun noprogrammer-debugger-hook-fun (condition old-debugger-hook)