Difference between revisions of "New CAT call"

m (Introcution)
m (Introcution)
Line 13: Line 13:
 
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<code>[eiffel, n]
 
<code>[eiffel, n]
class B
+
class B1
 
inherit A redefine f end
 
inherit A redefine f end
 
feature
 
feature
Line 21: Line 21:
 
|
 
|
 
<code>[eiffel, n]
 
<code>[eiffel, n]
class B
+
class B2
 
inherit A redefine f end
 
inherit A redefine f end
 
feature
 
feature

Revision as of 12:12, 27 October 2006

Introcution

The ECMA standard introduces a new solution to the CAT call problem. Covariant redefinition of a formal argument is only possible to an detatchable type:

class A
feature
   f (a: ANY) do end
end
class B1
inherit A redefine f end
feature
   f (a: STRING) do end   -- not valid
end
class B2
inherit A redefine f end
feature
   f (a: ?STRING) do end   -- valid
end