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From: "Robert I. Eachus" <eachus@mitre.org>
Subject: Re: Ammo-zilla
Date: 1999/10/29
Message-ID: <3819C484.224F12C9@mitre.org>#1/1
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Laurent Guerby wrote:
 
> Quite the contrary, garbage collection is allowed (but not mandated)
> by the language (see section 13.11.3 of the Ada 95 RM), and it's of
> course available for Ada compilers targetting the JVM.

    Actually there are some types for which it is mandated:

"Implementation Requirements

"No storage associated with an Unbounded_String object shall be lost
upon assignment or scope exit."  RM A.4.5(88)

    And those for which it is not recommended:

"Implementation Advice

"Bounded string objects should not be implemented by implicit pointers
and dynamic allocation."

    However I think that one of the easiest and most needed language
extensions is to have storage pools with reference counting and with
garbage collection predefined.  (Probably as generic children of
Ada.Finalization.)  The first is easily written in a portable manner,
but doing GC right for arbitrary types requires compiler
support/modifications.  (There are various methods, but all require that
access values for that storage pool contain more than a simple
pointer.)  You can create a storage pool with garbage collection
semantics without compiler support, but it requires discipline on the
part of the programmer.  (For example, you create a handle type, and
objects designated by handles are treated as referenced during GC, while
pointers and 'Access do not cause an object to be recognized as in use.)
-- 

                                        Robert I. Eachus

with Standard_Disclaimer;
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function Message (Text: in Clever_Ideas) return Better_Ideas is...