[54] in java-interest
Instanceof and type Coercion.
daemon@ATHENA.MIT.EDU (James Cownie)
Fri May 5 14:54:02 1995
Date: Fri, 5 May 1995 14:23:32 +0000
From: jim@meiko.co.uk (James Cownie)
To: java-interest@java.Eng.Sun.COM
> These are the notes on the Java Language meeting of Thursday the 4th of May.
...
> (7) Instanceof and type Coercion. Postponed. It turns out that
> you often write code like:
>
> if (x instanceof Foo) {
> Foo foox = (Foo)x;
> ...
> }
>
> It would be nice if there was some construct where you could
> test if x is an instance of Foo and then use it as a Foo
> without having to cast it. We could not agree on a good syntax
> that would have little impact on the language and the runtime.
It seems like you're after something similar to the C++ "dynamic_cast"
operator (discussed at some length by Stroustroup on page 308 of
Design and Evolution of C++). Of course you don't need all the
grievous syntax associated with it there :-). He does make some
reasonable arguments for why combining the test and cast is a good
thing.
-- Jim
James Cownie
Meiko Limited Meiko Inc.
650 Aztec West 130C Baker Avenue Ext.
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