batch-mode? in terms of *repl-level*

* module/ice-9/boot-9.scm (*repl-level*): New global fluid, moved here
  from (system repl common).
  (batch-mode?): Reimplement in terms of *repl-level*.
  (ensure-batch-mode!): A replacement for set-batch-mode?!.

* module/ice-9/deprecated.scm (set-batch-mode?!): Deprecate.

* module/ice-9/popen.scm (open-process): Use ensure-batch-mode!.

* module/ice-9/scm-style-repl.scm (error-catching-loop): Override
  ensure-batch-mode!.

* module/system/repl/common.scm: Remove *repl-level*.

module/ice-9/boot-9.scm

@@ -2661,6 +2661,7 @@ module '(ice-9 q) '(make-q q-length))}."
 ;;; Currently Guile represents unspecified values via one particular value,
 ;;; which may be obtained by evaluating (if #f #f). It would be nice in the
 ;;; future if we could replace this with a return of 0 values, though.
+;;;
 
 (define-syntax *unspecified*
   (identifier-syntax (if #f #f)))
@@ -2691,10 +2692,20 @@ module '(ice-9 q) '(make-q q-length))}."
 
 (define abort-hook (make-hook))
 
-;; these definitions are used if running a script.
-;; otherwise redefined in error-catching-loop.
-(define (set-batch-mode?! arg) #t)
-(define (batch-mode?) #t)
+;; Programs can call `batch-mode?' to see if they are running as part of a
+;; script or if they are running interactively. REPL implementations ensure that
+;; `batch-mode?' returns #f during their extent.
+;;
+;; Programs can re-enter batch mode, for example after a fork, by calling
+;; `ensure-batch-mode!'. This will also restore signal handlers. It's not a
+;; great interface, though; it would be better to abort to the outermost prompt,
+;; and call a thunk there.
+(define *repl-level* (make-fluid))
+(define (batch-mode?)
+  (negative? (or (fluid-ref *repl-level*) -1)))
+(define (ensure-batch-mode!)
+  (fluid-set! *repl-level* #f)
+  (restore-signals))
 
 ;;(define the-last-stack (make-fluid)) Defined by scm_init_backtrace ()
 (define before-signal-stack (make-fluid))

module/ice-9/deprecated.scm

@@ -54,7 +54,8 @@
             assert-repl-silence
             assert-repl-print-unspecified
             assert-repl-verbosity
-            set-repl-prompt!)
+            set-repl-prompt!
+            set-batch-mode?!)
 
   #:replace (module-ref-submodule module-define-submodule!))
 
@@ -595,3 +596,15 @@ better yet, use the repl from `(system repl repl)'.")
    "`set-repl-prompt!' is deprecated. Use `repl-default-prompt-set!' from
 the `(system repl common)' module.")
   ((@ (system repl common) repl-default-prompt-set!) v))
+
+(define (set-batch-mode?! arg)
+  (cond
+   (arg
+    (issue-deprecation-warning
+     "`set-batch-mode?!' is deprecated. Use `ensure-batch-mode!' instead.")
+    (ensure-batch-mode!))
+   (else
+    (issue-deprecation-warning
+     "`set-batch-mode?!' with an argument of `#f' is deprecated. Use the
+`*repl-level*' fluid instead.")
+    #t)))

module/ice-9/popen.scm

@@ -1,6 +1,6 @@
 ;; popen emulation, for non-stdio based ports.
 
-;;;; Copyright (C) 1998, 1999, 2000, 2001, 2003, 2006 Free Software Foundation, Inc.
+;;;; Copyright (C) 1998, 1999, 2000, 2001, 2003, 2006, 2010 Free Software Foundation, Inc.
 ;;;; 
 ;;;; This library is free software; you can redistribute it and/or
 ;;;; modify it under the terms of the GNU Lesser General Public
@@ -59,7 +59,7 @@
     (let ((pid (primitive-fork)))
       (cond ((= pid 0)
 	     ;; child
-	     (set-batch-mode?! #t)
+	     (ensure-batch-mode!)
 
 	     ;; select the three file descriptors to be used as
 	     ;; standard descriptors 0, 1, 2 for the new

module/ice-9/scm-style-repl.scm

@@ -129,12 +129,9 @@
                     default-pre-unwind-handler)))
 
         (if next (loop next) status)))
-    (set! set-batch-mode?! (lambda (arg)
-                             (cond (arg
-                                    (set! interactive #f)
-                                    (restore-signals))
-                                   (#t
-                                    (error "sorry, not implemented")))))
+    (set! ensure-batch-mode! (lambda ()
+                               (set! interactive #f)
+                               (restore-signals)))
     (set! batch-mode? (lambda () (not interactive)))
     (call-with-blocked-asyncs
      (lambda () (loop (lambda () #t))))))

module/system/repl/common.scm

@@ -30,8 +30,7 @@
             repl-parse repl-print repl-option-ref repl-option-set!
             repl-default-option-set! repl-default-prompt-set!
             puts ->string user-error
-            *warranty* *copying* *version*
-            *repl-level*))
+            *warranty* *copying* *version*))
 
 (define *version*
   (format #f "GNU Guile ~A
@@ -95,8 +94,6 @@ copy of the Program in return for a fee.
 
 See <http://www.gnu.org/licenses/lgpl.html>, for more details.")
 
-(define *repl-level* (make-fluid))
-
 
 ;;;
 ;;; Repl type