diff -r be947d4e7fb2 -r 514c749165c3 Signal.st
--- a/Signal.st	Mon Oct 10 01:29:01 1994 +0100
+++ b/Signal.st	Mon Oct 10 01:29:28 1994 +0100
@@ -1,6 +1,6 @@
 "
  COPYRIGHT (c) 1993 by Claus Gittinger
-              All Rights Reserved
+	      All Rights Reserved
 
  This software is furnished under a license and may be used
  only in accordance with the terms of that license and with the
@@ -11,18 +11,18 @@
 "
 
 Object subclass:#Signal
-         instanceVariableNames:'mayProceed notifierString nameClass message
-                                handlerBlock'
-         classVariableNames:'NoHandlerSignal'
-         poolDictionaries:''
-         category:'Kernel-Exceptions'
+	 instanceVariableNames:'mayProceed notifierString nameClass message
+				handlerBlock parent'
+	 classVariableNames:'NoHandlerSignal RecursiveRaiseSignal'
+	 poolDictionaries:''
+	 category:'Kernel-Exceptions'
 !
 
 Signal comment:'
 COPYRIGHT (c) 1993 by Claus Gittinger
-              All Rights Reserved
+	      All Rights Reserved
 
-$Header: /cvs/stx/stx/libbasic/Signal.st,v 1.13 1994-08-23 23:11:14 claus Exp $
+$Header: /cvs/stx/stx/libbasic/Signal.st,v 1.14 1994-10-10 00:28:19 claus Exp $
 '!
 
 !Signal class methodsFor:'documentation'!
@@ -30,7 +30,7 @@
 copyright
 "
  COPYRIGHT (c) 1993 by Claus Gittinger
-              All Rights Reserved
+	      All Rights Reserved
 
  This software is furnished under a license and may be used
  only in accordance with the terms of that license and with the
@@ -43,7 +43,7 @@
 
 version
 "
-$Header: /cvs/stx/stx/libbasic/Signal.st,v 1.13 1994-08-23 23:11:14 claus Exp $
+$Header: /cvs/stx/stx/libbasic/Signal.st,v 1.14 1994-10-10 00:28:19 claus Exp $
 "
 !
 
@@ -98,22 +98,22 @@
 
     Instance variables:
 
-        mayProceed      <Boolean>       hint for the debugger - program may 
-                                        proceed (currently not honored by the
-                                        debugger)
+	mayProceed      <Boolean>       hint for the debugger - program may 
+					proceed (currently not honored by the
+					debugger)
 
-        notifierString  <String>        eror message to be output 
+	notifierString  <String>        eror message to be output 
 
-        nameClass       <???>           I dont know what this is for 
-                                        (included for ST-80 compatibility)
+	nameClass       <???>           I dont know what this is for 
+					(included for ST-80 compatibility)
 
-        message         <???>           I dont know what this is for
-                                        (included for ST-80 compatibility)
+	message         <???>           I dont know what this is for
+					(included for ST-80 compatibility)
 
-        handlerBlock    <Block>         if nonNil, a 1-arg block to be 
-                                        evaluated when no handler context is 
-                                        found. The block gets the exception
-                                        object as argument.
+	handlerBlock    <Block>         if nonNil, a 1-arg block to be 
+					evaluated when no handler context is 
+					found. The block gets the exception
+					object as argument.
 
     Notice:
     Part of the implementation is a left-over from old times when the 
@@ -125,12 +125,19 @@
 
 !Signal class methodsFor:'initialization'!
 
-initialize
+initialize 
     "setup the signal used to handle unhandled signals"
 
     NoHandlerSignal isNil ifTrue:[
-        NoHandlerSignal := (Signal new) mayProceed:true.
-        NoHandlerSignal notifierString:'unhandled exception'
+	Object initialize.
+
+	NoHandlerSignal := Object errorSignal newSignalMayProceed:true.
+	NoHandlerSignal nameClass:self message:#noHandlerSignal.
+	NoHandlerSignal notifierString:'unhandled exception'.
+
+	RecursiveRaiseSignal := Object errorSignal newSignalMayProceed:false.
+	RecursiveRaiseSignal nameClass:self message:#recursiveRaiseSignal.
+	RecursiveRaiseSignal notifierString:'recursive signal raise'
     ]
 ! !
 
@@ -148,26 +155,49 @@
     "return the signal used to handle unhandled signals"
 
     ^ NoHandlerSignal
+!
+
+recursiveRaiseSignal
+    "return the signal used to handle recursive signal raises"
+
+    ^ RecursiveRaiseSignal
 ! !
 
 !Signal methodsFor:'instance creation'!
 
 newSignalMayProceed:aBoolean
-    "create a new signal, using the receiver as a prototype"
+    "create a new signal, using the receiver as a prototype and
+     setting the parent of the new signal to the receiver."
 
-    ^ (self copy) mayProceed:aBoolean
+    |newSignal|
+
+    newSignal := (self copy) mayProceed:aBoolean.
+    newSignal parent:self.
+    ^ newSignal
 !
 
 newSignal
-    "create a new signal, using the receiver as a prototype"
+    "create a new signal, using the receiver as a prototype and
+     setting the parent of the new signal to the receiver."
+
+    ^ (self copy) parent:self
+! !
 
-    ^ (self copy)
+!Signal methodsFor:'copying'!
+
+deepCopy
+    "raise an error - deepCopy is not allowed for signals"
+
+    ^ self deepCopyError
 ! !
 
 !Signal methodsFor:'accessing'!
 
 nameClass:aClass message:aSelector
-    "I dont know what that is used for (yet)"
+    "this sets the class & selector of a method which returns
+     that signal - this is simply for documentation purposes -
+     see Signal>>printOn: implementation.
+     (took me a while to find that one out ;-)"
 
     nameClass := aClass.
     message := aSelector
@@ -181,6 +211,18 @@
     mayProceed := aBoolean
 !
 
+parent:aSignal 
+    "set the parent-signal of the receiver."
+
+    parent := aSignal
+!
+
+parent
+    "return the parent-signal of the receiver"
+
+    ^ parent
+!
+
 notifierString:aString
     "set the notifier string"
 
@@ -200,6 +242,20 @@
     handlerBlock := aOneArgBlock
 ! !
 
+!Signal methodsFor:'printing'!
+
+printOn:aStream
+    "append a printed representation of the receiver on aStream"
+
+    nameClass notNil ifTrue:[
+	aStream nextPutAll:nameClass name.
+	aStream space.
+	aStream nextPutAll:message.
+	^ self
+    ].
+    ^ super printOn:aStream
+! !
+
 !Signal methodsFor:'save evaluation'!
 
 handle:handleBlock do:aBlock
@@ -215,10 +271,10 @@
 
       "
        Object messageNotUnderstoodSignal handle:[:ex |
-          'oops' printNL.
-          ex return
+	  'oops' printNL.
+	  ex return
        ] do:[
-          123 size open   
+	  123 size open   
        ]
       "
 
@@ -227,18 +283,18 @@
 
        num := 0.
        Number divisionByZeroSignal handle:[:ex |
-          'oops' printNL.
-          ex return
+	  'oops' printNL.
+	  ex return
        ] do:[
-          123 / num   
+	  123 / num   
        ]
       "
 !
 
 catch:aBlock
-     "evaluate the argument, aBlock; return false.
+     "evaluate the argument, aBlock.
       If the receiver-signal is raised during evaluation, abort
-      the evaluation and return true. 
+      the evaluation and return true; otherwise return false. 
       This is the catch & throw mechanism found in other languages,
       where the returned value indicates if an exception occured."
 
@@ -250,13 +306,43 @@
 
       "
        Object messageNotUnderstoodSignal catch:[
-          123 size open   
+	  123 size open   
+       ]
+      "
+!
+
+ignore:aBlock
+     "evaluate the argument, aBlock.
+      Ignore the receiver-signal during evaluation - i.e. simply
+      continue. This makes only sense for some signals, such as UserInterrupt
+      or AbortSignals, because continuing after an exception without any cleanup
+      will often lead to followup-errors."
+
+      ^ self handle:[:ex | ex proceed] do:aBlock.
+
+      "
+       Object messageNotUnderstoodSignal ignore:[
+	  123 size open   
        ]
       "
 ! !
 
 !Signal methodsFor:'queries'!
 
+accepts:aSignal
+    "return true, if the receiver accepts the argument, aSignal.
+     (i.e. the recevier is aSignal or a parent of it). False otherwise."
+
+    |s|
+
+    s := aSignal.
+    [s notNil] whileTrue:[
+	self == s ifTrue:[^ true].
+	s := s parent
+    ].
+    ^ false
+!
+
 isHandled
     "return true, if there is a handler for the receiver signal.
      Raising an unhandled signal will usually lead into the debugger,
@@ -267,19 +353,18 @@
     con := thisContext.
     con := con sender.
     [con notNil] whileTrue:[
-        (con selector == #handle:do:) ifTrue:[
-            "
-             is this is the Signal>>handle:do: context
-             or a SignalSet>>handle:do: context with self in it ?
-            "
-            ((con receiver == self) 
-            or:[(con receiver isMemberOf:SignalSet) and:[con receiver includes:self]]) ifTrue:[
-                "found it"
+	(con selector == #handle:do:) ifTrue:[
+	    "
+	     is this is the Signal>>handle:do: context
+	     or a SignalSet>>handle:do: context with self in it ?
+	    "
+	    (con receiver accepts:self) ifTrue:[
+		"found a handler context"
 
-                ^ true
-            ].
-        ].
-        con := con sender
+		^ true
+	    ].
+	].
+	con := con sender
     ].
     ^ false
 ! !
@@ -298,34 +383,41 @@
     |ex block|
 
     ex := Exception new 
-              signal:self
-              parameter:nil 
-              errorString:notifierString
-              suspendedContext:thisContext sender.
+	      signal:self
+	      parameter:nil 
+	      errorString:notifierString
+	      suspendedContext:thisContext sender.
 
     ex resumeBlock:[:value | ^ value].
     self evaluateHandlerWith:ex.
 
     (block := handlerBlock) isNil ifTrue:[
-        "
-         if I am not the NoHandlerSignal, raise it ...
-         passing the exception as parameter.
-        "
-        self == NoHandlerSignal ifFalse:[
-            ^ NoHandlerSignal 
-                  raiseRequestWith:ex
-                       errorString:('unhandled exception: ' , ex errorString)
-        ].
+	"
+	 if I am not the NoHandlerSignal, raise it ...
+	 passing the exception as parameter.
+	"
+	self == NoHandlerSignal ifFalse:[
+	    ^ NoHandlerSignal 
+		  raiseRequestWith:ex
+		       errorString:('unhandled exception: ' , ex errorString)
+	].
 
-        "
-         otherwise,
-         take either a per-process emergencyHandlerBlock 
-         or the global emergencyHandler (from Exception) ...
-        "
-        block := Processor activeProcess emergencySignalHandler.
-        block isNil ifTrue:[
-            block := Exception emergencyHandler
-        ]
+	"
+	 otherwise,
+	 take either a per-process emergencyHandlerBlock 
+	 or the global emergencyHandler (from Exception) ...
+	"
+	Processor notNil ifTrue:[ 
+	    "care for signal during startup (Processor not yet created)"
+	    block := Processor activeProcess emergencySignalHandler.
+	].
+	block isNil ifTrue:[
+	    block := Exception emergencyHandler
+	].
+	block isNil ifTrue:[
+	    "care for error during startup (Exception not yet initialized)"
+	    ^ MiniDebugger enterWithMessage:ex errorString
+	]
     ].
 
     "... and call it"
@@ -344,34 +436,41 @@
     |ex block|
 
     ex := Exception new 
-              signal:self
-              parameter:aParameter 
-              errorString:notifierString
-              suspendedContext:thisContext sender.
+	      signal:self
+	      parameter:aParameter 
+	      errorString:notifierString
+	      suspendedContext:thisContext sender.
 
     ex resumeBlock:[:value | ^ value].
     self evaluateHandlerWith:ex.
 
     (block := handlerBlock) isNil ifTrue:[
-        "
-         if I am not the NoHandlerSignal, raise it ...
-         passing the exception as parameter.
-        "
-        self == NoHandlerSignal ifFalse:[
-            ^ NoHandlerSignal 
-                  raiseRequestWith:ex
-                       errorString:('unhandled exception: ' , ex errorString)
-        ].
+	"
+	 if I am not the NoHandlerSignal, raise it ...
+	 passing the exception as parameter.
+	"
+	self == NoHandlerSignal ifFalse:[
+	    ^ NoHandlerSignal 
+		  raiseRequestWith:ex
+		       errorString:('unhandled exception: ' , ex errorString)
+	].
 
-        "
-         otherwise,
-         take either a per-process emergencyHandlerBlock 
-         or the global emergencyHandler (from Exception) ...
-        "
-        block := Processor activeProcess emergencySignalHandler.
-        block isNil ifTrue:[
-            block := Exception emergencyHandler
-        ]
+	"
+	 otherwise,
+	 take either a per-process emergencyHandlerBlock 
+	 or the global emergencyHandler (from Exception) ...
+	"
+	Processor notNil ifTrue:[ 
+	    "care for signal during startup (Processor not yet created)"
+	    block := Processor activeProcess emergencySignalHandler.
+	].
+	block isNil ifTrue:[
+	    block := Exception emergencyHandler
+	].
+	block isNil ifTrue:[
+	    "care for error during startup (Exception not yet initialized)"
+	    ^ MiniDebugger enterWithMessage:ex errorString
+	]
     ].
 
     "... and call it"
@@ -387,34 +486,41 @@
     |ex block|
 
     ex := Exception new 
-              signal:self
-              parameter:nil
-              errorString:something printString
-              suspendedContext:thisContext sender.
+	      signal:self
+	      parameter:nil
+	      errorString:something printString
+	      suspendedContext:thisContext sender.
 
     ex resumeBlock:[:value | ^ value].
     self evaluateHandlerWith:ex.
 
     (block := handlerBlock) isNil ifTrue:[
-        "
-         if I am not the NoHandlerSignal, raise it ...
-         passing the exception as parameter.
-        "
-        self == NoHandlerSignal ifFalse:[
-            ^ NoHandlerSignal 
-                  raiseRequestWith:ex
-                       errorString:('unhandled exception: ' , ex errorString)
-        ].
+	"
+	 if I am not the NoHandlerSignal, raise it ...
+	 passing the exception as parameter.
+	"
+	self == NoHandlerSignal ifFalse:[
+	    ^ NoHandlerSignal 
+		  raiseRequestWith:ex
+		       errorString:('unhandled exception: ' , ex errorString)
+	].
 
-        "
-         otherwise,
-         take either a per-process emergencyHandlerBlock 
-         or the global emergencyHandler (from Exception) ...
-        "
-        block := Processor activeProcess emergencySignalHandler.
-        block isNil ifTrue:[
-            block := Exception emergencyHandler
-        ]
+	"
+	 otherwise,
+	 take either a per-process emergencyHandlerBlock 
+	 or the global emergencyHandler (from Exception) ...
+	"
+	Processor notNil ifTrue:[ 
+	    "care for signal during startup (Processor not yet created)"
+	    block := Processor activeProcess emergencySignalHandler.
+	].
+	block isNil ifTrue:[
+	    block := Exception emergencyHandler
+	].
+	block isNil ifTrue:[
+	    "care for error during startup (Exception not yet initialized)"
+	    ^ MiniDebugger enterWithMessage:ex errorString
+	]
     ].
 
     "... and call it"
@@ -429,34 +535,41 @@
     |ex block|
 
     ex := Exception new 
-              signal:self
-              parameter:aParameter 
-              errorString:aString
-              suspendedContext:thisContext sender.
+	      signal:self
+	      parameter:aParameter 
+	      errorString:aString
+	      suspendedContext:thisContext sender.
 
     ex resumeBlock:[:value | ^ value].
     self evaluateHandlerWith:ex.
 
     (block := handlerBlock) isNil ifTrue:[
-        "
-         if I am not the NoHandlerSignal, raise it ...
-         passing the exception as parameter.
-        "
-        self == NoHandlerSignal ifFalse:[
-            ^ NoHandlerSignal 
-                  raiseRequestWith:ex
-                       errorString:('unhandled exception: ' , ex errorString)
-        ].
+	"
+	 if I am not the NoHandlerSignal, raise it ...
+	 passing the exception as parameter.
+	"
+	self == NoHandlerSignal ifFalse:[
+	    ^ NoHandlerSignal 
+		  raiseRequestWith:ex
+		       errorString:('unhandled exception: ' , ex errorString)
+	].
 
-        "
-         otherwise,
-         take either a per-process emergencyHandlerBlock 
-         or the global emergencyHandler (from Exception) ...
-        "
-        block := Processor activeProcess emergencySignalHandler.
-        block isNil ifTrue:[
-            block := Exception emergencyHandler
-        ]
+	"
+	 otherwise,
+	 take either a per-process emergencyHandlerBlock 
+	 or the global emergencyHandler (from Exception) ...
+	"
+	Processor notNil ifTrue:[ 
+	    "care for signal during startup (Processor not yet created)"
+	    block := Processor activeProcess emergencySignalHandler.
+	].
+	block isNil ifTrue:[
+	    block := Exception emergencyHandler
+	].
+	block isNil ifTrue:[
+	    "care for error during startup (Exception not yet initialized)"
+	    ^ MiniDebugger enterWithMessage:ex errorString
+	]
     ].
 
     "... and call it"
@@ -465,9 +578,10 @@
 
 !Signal methodsFor:'private'!
 
-evaluateHandlerWith:anException
+evaluateHandlerWith:ex
     "search through the context-calling chain for a 'handle:do:'-context 
-     to the receiver or a SignalSet which includes the receiver.
+     to the receiver or a parent of the receiver or a SignalSet which includes 
+     the receiver.
      If found, take its 2nd argument (the handler) and evaluate
      it with the exception as argument.
      If none found, just return."
@@ -477,34 +591,43 @@
     con := thisContext.
     con := con sender.
     con isRecursive ifTrue:[
-        "
-         mhmh - an error while in a handler
-         go immediately into the debugger.
-        "
-        ^ self enterDebuggerWith:anException
-                         message:'recursive signal raise'
+	"
+	 mhmh - an error while in a handler
+	"
+	((self == RecursiveRaiseSignal)
+	or:[RecursiveRaiseSignal isNil]) ifTrue:[
+	    "
+	     ... either while handling RecursiveSignal
+	     or at startup when RecursiveSignal is not yet
+	     created -
+	     - go immediately into the debugger.
+	    "
+	    ^ self enterDebuggerWith:ex
+			     message:'recursive signal raise'
+	].
+	^ RecursiveRaiseSignal 
+	    raiseRequestWith:ex
+		 errorString:('recursive signal raise: ' , ex errorString)
     ].
 
     [con notNil] whileTrue:[
-        (con selector == #'handle:do:') ifTrue:[
-            "
-             if this is the Signal>>handle:do: context
-             or a SignalSet>>handle:do: context with self in it,
-             call the handler
-            "
-            ((con receiver == self) 
-            or:[(con receiver isMemberOf:SignalSet) 
-                and:[con receiver includes:self]]) ifTrue:[
-                "call the handler"
+	(con selector == #'handle:do:') ifTrue:[
+	    "
+	     if this is the Signal>>handle:do: context
+	     or a SignalSet>>handle:do: context with self in it,
+	     call the handler
+	    "
+	    (con receiver accepts:self) ifTrue:[
+		"call the handler"
 
-                anException handlerContext:con.
-                self doCallHandler:(con args at:1) with:anException.
+		ex handlerContext:con.
+		self doCallHandler:(con args at:1) with:ex.
 
-                "if the handler rejects or falls through we arrive here"
-                "continue search for another handler"
-            ].
-        ].
-        con := con sender
+		"if the handler rejects or falls through we arrive here"
+		"continue search for another handler"
+	    ].
+	].
+	con := con sender
     ].
 
     "