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   555 raiseAsQuery

   556     "utility to avoid code duplication.

   557      raise the exception as a query. This means, that if it is unhandled,

   558      a default value is returned (i.e. an implicit resume).

   559      Return the handler's value (if there is one), or the default value, if not.

   560      Invoking the handler is exactly the functionality of Signal>>raiseRequest,

   561      but we can do it faster here (avoiding the construction of an exception instance)."

   562 

   563     |con signal ret|

   564 

   565     self isQuerySignal ifFalse:[ self error:'this may only be used by queries' ].

   566 

   567     con := Context findFirstSpecialHandle:true raise:false.

   568     [con notNil] whileTrue:[

   569         (con selector == #answer:do:) ifTrue:[ 

   570             signal := con receiver.

   571             signal == self ifTrue:[

   572                 ret := con argAt:1.

   573                 con := nil.

   574                 ^ ret

   575             ].

   576             signal isNil ifTrue:[

   577                 self error:'nil receiver in #answer:do: - send'.

   578             ].

   579             (signal accepts:self) ifTrue:[

   580                 ret := con argAt:1.

   581                 con := nil.

   582                 ^ ret

   583             ].

   584         ] ifFalse:[

   585             "ask the the receiver of the #handle:do: or #on:do: or whatever- message for the handler.

   586              nil is returned, if the signal is not accepted"

   587             |r|

   588             r := con receiver.     "receiver of #handle:do: or #on:do:"

   589             (r notNil and:[(r handlerForSignal:self

   590                                  context:con

   591                                  originator:thisContext sender homeReceiver) notNil]

   592             ) ifTrue:[

   593                 "there is another handler block, maybe it will return the answer.

   594                  Call it via raiseRequest"

   595                 con := nil.

   596                 ^ here raiseRequest  "/ <- notice the here, to avoid recursion due

   597                                      "/ to redefined raiseRequest in Query

   598             ].

   599         ].

   600         con := con findSpecialHandle:true raise:false.

   601     ].

   602 

   603     "/ no handler found - return the default value

   604     ^ self defaultAnswer

   605 

   606     "Modified: / 15-06-1998 / 21:27:37 / cg"

   607     "Modified: / 25-07-1999 / 23:15:16 / stefan"

   608     "Modified: / 11-03-2015 / 11:26:45 / sr"

   609 !

   610