what is Exception>>#return:?

What is the difference between:

[ "something" ]
    on: Error
    do: [ : err | err return: nil ]

and:

[ "something" ]
    on: Error
    do: [ : err | nil ]

?

Thanks.

There's no difference in your example. #return: is useful if your error
handler code is not in argument block of #on:do:. E.g.:

handler := [ :anError |
  anError messageText = 'boo' ifTrue: [
  anError return: 'It was boo.' ].
  "We only reach this point if the message was not 'boo'"
  'Not boo.' ].

{
[ self error: 'boo' ]
  on: Error
  do: [ :err | handler value: err ].
[ self error: 'foo' ]
  on: Error
  do: [ :err | handler value: err ] }


Levente

On Wed, 20 Nov 2013, Chris Muller wrote:

Hi Chris,

>    do: [ : err | err return: nil ]

 #on:do: send will return the result of sending
 #return: message to the object that is named
 "err" in the argument context...
 incase that message succeded to return... ;-)

>    do: [ : err | nil ]

is granted to return nil by "black box magic" of exceptions
 mechanism; and there is no way to change that
 without modifying the method.

cheers,
Ale.


----- Original Message -----
From: "Chris Muller" <[hidden email]>
To: "squeak dev" <[hidden email]>
Sent: Wednesday, November 20, 2013 10:59 PM
Subject: [squeak-dev] what is Exception>>#return:?