PROPOSAL: 'final' without explicit type (update) (original) (raw)

Gabriel Belingueres belingueres at gmail.com
Mon Mar 30 18:06:38 PDT 2009

2009/3/30 Marek Kozieł <develop4lasu at gmail.com>:

W dniu 31 marca 2009 00:45 użytkownik Gabriel Belingueres <belingueres at gmail.com> napisał:

Hi Marek:

- VariableInitializer type is neither primitive nor Object.  --> primitive : they should not be mixed with Object-s to easy.  --> Object : when object type is Object, we mostly deal with situation 'Unknown type', so this should not be hidden. I still don't get why it is so bad to do something like this: final a = 1; // static type is int or final o = new Object(); // static type is Object, no doubt I still don't see the point on not making this feature more orthogonal (unless some convincing argument is presented against it.)

For primitives I would prefer: primitive a = 1; // a is int / short / byte rather than: final a = 1; // static type is int Primitives represent other level of abstraction and mixing them will make people to be confused (more or less).

Why? final a = 1; // static type is int final b = new Integer(6); // static type is Integer

If this is confusing for someone: final c = 1 + new Integer(7);

then declare it as usual.

final o = new Object(); // in this form it's ok

here I see problem: final o = some.getBoo().getLocalization(); // o is Object For some reason we did not ensured valid type to be returned, so we should care about it while declaring 'o', or say that we do not care: final o = (Localization) some.getBoo().getLocalization(); final Object o = some.getBoo().getLocalization();

Assuming that getLocalization() returns a Localization, then the whole point is that you don't need the cast; otherwise this feature is of doubtful utility. The variable type is known at compile type to be a Localization. OTOH, if the getLocalization() returns an Object, then final o = (Localization) some.getBoo().getLocalization(); might throw a ClassCastException at runtime, which is a pity because this is a new feature. If you want to risk to receive a ClassCastException, then declare it as usual: final Localization o = (Localization) some.getBoo().getLocalization();

IMHO, type casts should be forbidden, or at least discouraged.

If we allow final to be ANY type, then backing to declaration will be required just to make correction, this will piss off programmers.

So primitives and Object-s are special types and should be handled in this way. -- Pozdrowionka. / Regards. Lasu aka Marek Kozieł http://lasu2string.blogspot.com/

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