Additional PREPARE argument for with-inspecting-handler

scsh/interaction/README

@@ -19,7 +19,7 @@ Same as above but communication is done via a socket on port PORT.
 The structure SOCKET2STDPORTS offers a very simple facility to map the
 current input and output ports to the ports of a socket.
 
-(socket<->std-ports host port)
+(socket<->stdports host port)
 
 This procedure first establishes a TCP socket to port PORT on host
 HOST. Afterwards is reads all data from (current-input-port) and
@@ -28,27 +28,32 @@ from the socket's output port and prints it to
 (current-output-port).
 
 
-(with-inspecting-handler port thunk)
+(with-inspecting-handler port prepare thunk)
 
 This procedure installs a exception handler which captures all
-conditions which satisfy the predicate ERROR?. It will then fire up a
-remote REPL on port PORT with the continuation of the condition as
-focus value. Currently, the continuation of the REPL is the
-continuation of the call to WITH-INSPECTING-HANDLER.
+conditions which satisfy the predicate ERROR?. In case of an exception
+PREPARE is applied to the condition. If it returns #t,
+WITH-INSPECTING-HANDLER will fire up a remote REPL on port PORT with
+the continuation of the condition as focus value. Currently, the
+continuation of the REPL is the continuation of the call to
+WITH-INSPECTING-HANDLER. If PREPARE returns #f the surrounding handler
+is called.
 
 
 As an example for the usage of the remote inspecting utility, consider
 a program using WITH-INSPECTING-HANDLER with an obviously bogus body:
 
-(with-inspecting-handler 8080 (lambda () (/ 1 0)))
-
+>(with-inspecting-handler 8080 
+                        (lambda (cond) (display "Help me on port 8080") #t)
+                        (lambda () (/ 1 0)))
+Help me on port 8080
 
 Now start a second scsh:
 
 [0 gasbichl@ventoux interaction] scsh -lm interfaces.scm -lm packages.scm -o 'socket2stdports'
 Welcome to scsh 0.6.3
 Type ,? for help.
-> (socket<->std-ports "ventoux" 8080)
+> (socket<->stdports "ventoux" 8080)
 Welcome to the command processor of the remote scsh
 #{Exception-continuation (pc 69) (integer/ in ratnums)}
 > ,debug

scsh/interaction/inspect-exception.scm

@@ -22,13 +22,18 @@
 	       (more))))		; Keep looking for a handler.
 	  (lambda () (call-with-values thunk accept)))))))))
 
-(define (with-inspecting-handler port thunk)
+(define (with-inspecting-handler port prepare thunk)
   (with-fatal-and-capturing-error-handler*
    (lambda (condition condition-continuation more)
-     (let ((res
-	    (remote-repl "Welcome to the command processor of the remote scsh"
-			 condition-continuation
-			 port)))
-       ;; TODO: option to return to continuation of handler (by leaving out the with-continuation)
-       (with-continuation condition-continuation (lambda () res))))
-   thunk))
+     (with-handler
+      (lambda (c2 m2)
+        (more))      
+      (if (prepare condition)
+          (let ((res
+                 (remote-repl "Welcome to the command processor of the remote scsh"
+                              condition-continuation
+                              port)))
+            ;; TODO: option to return to continuation of handler (by leaving out the with-continuation)
+            (with-continuation condition-continuation (lambda () res)))
+          (more))))
+      thunk))