[new to smalltalk] confusing problem: BlockContext >> cannot return
herbertkoenig at gmx.net
Wed Nov 24 16:52:42 UTC 2004
I planned to come here with a question if something I did is
acceptable smalltalk (or Squeak) style but as it still doesn't work I
have to come with a bit of code first:
I simplified the problem so it can be copied into a workspace.
"This example string is to be converted into an object"
str := 'G 0.000 38.199 1 2 68150.071 97542.712'.
"As several types of strings have to be converted into different
objects I feed them into a kind of method dictionary: to avoid a
procedural case statement"
dict := Dictionary new.
dict add: 'G' -> ([ :aLine | ^ Random new.]);
"add: 'G' -> ([ :aLine | ^ ProjektAchsenReader myLineToLine:
add: 'B' -> ([ :aLine | ^ ProjektAchsenReader myLineToArc: aLine.]);
add: 'K' -> ([ :aLine | ^ ProjektAchsenReader myLineToKlotho: aLine.]).
"Printing the following to test the method used in the dictionary works as
expected, so any class method returning a value is usable, i used
ProjektAchsenReader myLineToLine: str " results in: an AchselementGerade"
"Trying this gives me a stack walkback and a headche :-)"
(dict at: 'G') value: str.
"The intention was to return an AchselementGerade"
The stack walkback:
" in UndefinedObject>>Doit"
Though "The receiver tried to return result to a method context that
no longer exists." is clear enough in plain english I don't know what
to make of it or how to get rid of it.
I'm sure I missed something fundamental, so please give me a clue!
Herbert mailto:herbertkoenig at gmx.net
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