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From: Jeffrey Carter <spam.jrcarter.not@spam.not.acm.org>
Newsgroups: comp.lang.ada
Subject: Re: Generics vs. O-O?
Date: Thu, 01 Aug 2013 13:35:57 -0700
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Date: 2013-08-01T13:35:57-07:00
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On 08/01/2013 01:10 PM, optikos@verizon.net wrote:
>
> Conversely, Ada utilizes a single instance of machine code & static data for
> an Ada generic, regardless of the type parameters passed at compile-time.
> This single instance of machine-code accommodates different type parameters
> by either branching (around different per-type-parameter treatment) or table
> look-up (of the size & structure of entities).  No such branching or
> table-lookup is present in the corresponding combinatorial explosion of C++
> template instantiation.  This conflation by branching or table look-up in Ada
> is precisely why the combinatorial explosion does not occur in Ada generics,
> as it does in C++ templates.

While Ada generics /can/ be implemented this way (see Janus/Ada for an instance 
proof), most Ada compilers do not implement generics this way, but do macro 
expansion (see GNAT for an example).

-- 
Jeff Carter
"I feel as though somebody stepped on my tongue
with muddy feet."
Never Give a Sucker an Even Break
112