Make the debugger (and consequently the Edwin debugger also) be able

to return TO (in addition to return FROM, which was on #\Z) the
subproblem.

diff --git a/v7/src/runtime/debug.scm b/v7/src/runtime/debug.scm
index 4f76099500012dbb7cf004b1581bb0accae1d84c..41e24207e93722b3227bf6d94fc187a7be40fa6b 100644 (file)
--- a/v7/src/runtime/debug.scm
+++ b/v7/src/runtime/debug.scm
@@ -1,6 +1,6 @@
 #| -*-Scheme-*-
 
-$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/runtime/debug.scm,v 14.29 1991/08/06 22:10:41 arthur Exp $
+$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/runtime/debug.scm,v 14.30 1991/08/28 22:30:31 arthur Exp $
 
 Copyright (c) 1988-91 Massachusetts Institute of Technology
 
@@ -166,6 +166,8 @@ MIT in each case. |#
           "prints a summary (History) of all subproblems")
       (#\I ,command/condition-report
           "redisplay the error message Info")
+      (#\J ,command/return-to
+          "return TO the current subproblem with a value")
       (#\K ,command/condition-restart
           "continue the program using a standard restart option")
       (#\L ,command/print-expression
@@ -192,8 +194,8 @@ MIT in each case. |#
           "create a read eval print loop in the debugger environment")
       (#\Y ,command/frame
           "display the current stack frame")
-      (#\Z ,command/return
-          "return (continue with) an expression after evaluating it")
+      (#\Z ,command/return-from
+          "return FROM the current subproblem with a value")
       )))
   (set! hook/debugger-before-return default/debugger-before-return)
   unspecific)
@@ -717,39 +719,45 @@ MIT in each case. |#
 (define (default/debugger-before-return)
   '())
 
-(define (command/return dstate)
+(define (enter-subproblem subproblem dstate)
+  (let ((invalid-expression?
+        (invalid-expression? (dstate/expression dstate)))
+       (environment (get-evaluation-environment dstate))
+       (return
+        (lambda (value)
+          (hook/debugger-before-return)
+          ((stack-frame->continuation subproblem) value))))
+    (let ((value
+          (let ((expression
+                 (prompt-for-expression
+                  (string-append
+                   "Expression to EVALUATE and CONTINUE with"
+                   (if invalid-expression?
+                       ""
+                       " ($ to retry)")))))
+            (if (and (not invalid-expression?)
+                     (eq? expression '$))
+                (debug/scode-eval (dstate/expression dstate)
+                                  environment)
+                (debug/eval expression environment)))))
+      (if debugger:print-return-values?
+         (begin
+           (newline)
+           (write-string "That evaluates to:")
+           (newline)
+           (write value)
+           (if (prompt-for-confirmation "Confirm") (return value)))
+         (return value)))))
+
+(define (command/return-from dstate)
   (let ((next (stack-frame/next-subproblem (dstate/subproblem dstate))))
     (if next
-       (let ((invalid-expression?
-              (invalid-expression? (dstate/expression dstate)))
-             (environment (get-evaluation-environment dstate))
-             (return
-              (lambda (value)
-                (hook/debugger-before-return)
-                ((stack-frame->continuation next) value))))
-         (let ((value
-                (let ((expression
-                       (prompt-for-expression
-                        (string-append
-                         "Expression to EVALUATE and CONTINUE with"
-                         (if invalid-expression?
-                             ""
-                             " ($ to retry)")))))
-                  (if (and (not invalid-expression?)
-                           (eq? expression '$))
-                      (debug/scode-eval (dstate/expression dstate)
-                                        environment)
-                      (debug/eval expression environment)))))
-           (if debugger:print-return-values?
-               (begin
-                 (newline)
-                 (write-string "That evaluates to:")
-                 (newline)
-                 (write value)
-                 (if (prompt-for-confirmation "Confirm") (return value)))
-               (return value))))
+       (enter-subproblem next dstate)
        (debugger-failure "Can't continue!!!"))))
 
+(define (command/return-to dstate)
+  (enter-subproblem (dstate/subproblem dstate) dstate))
+
 (define *dstate*)
 
 (define (command/internal dstate)