From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham
	autolearn_force=no version=3.4.4
X-Google-Thread: 103376,ce306343df782d85
X-Google-Attributes: gid103376,public
X-Google-Language: ENGLISH,ASCII-7-bit
Path: 
 g2news1.google.com!news4.google.com!newshub.sdsu.edu!elnk-nf2-pas!newsfeed.earthlink.net!stamper.news.pas.earthlink.net!stamper.news.atl.earthlink.net!newsread2.news.atl.earthlink.net.POSTED!14bb18d8!not-for-mail
Sender: mheaney@MHEANEYX200
Newsgroups: comp.lang.ada
Subject: Re: Newbie - HashMap!
References: <1111061037.535775.69180@l41g2000cwc.googlegroups.com>
 <42399f5c$0$26540$9b4e6d93@newsread4.arcor-online.net>
From: Matthew Heaney <matthewjheaney@earthlink.net>
Message-ID: <uwts1n8hn.fsf@earthlink.net>
User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.3
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Date: Mon, 21 Mar 2005 00:33:08 GMT
NNTP-Posting-Host: 24.149.57.125
X-Complaints-To: abuse@earthlink.net
X-Trace: newsread2.news.atl.earthlink.net 1111365188 24.149.57.125 (Sun,
 20 Mar 2005 16:33:08 PST)
NNTP-Posting-Date: Sun, 20 Mar 2005 16:33:08 PST
Organization: EarthLink Inc. -- http://www.EarthLink.net
Xref: g2news1.google.com comp.lang.ada:9653
Date: 2005-03-21T00:33:08+00:00
List-Id: <comp.lang.ada>

Georg Bauhaus <bauhaus@futureapps.de> writes:

>    package Lookup_tables is
>       new Ada.Containers.Hashed_Maps (Unbounded_String,
>                                       Unbounded_String,
>                                       Equivalent_Keys => "=",
>                                       Hash => Hash);

Strictly speaking, the C++ example used type std::string, and the Ada
analog of that type is probably Unbounded_String, so what you have above
is technically correct.

However, Ada doesn't have constructors like you have in C++, that
automatically convert a const char* to std::string, so what you have
above is going to be awkward to use.  Therefore, I recommend the
indefinite hashed map instead:

package Lookup_Tables is
  new Ada.Containers.Indefinite_Hashed_Map 
    (String,
     String,
     Hash,
     "=");

Now you can using type String directly:

  Include (HM, "Key", "Value");  --yes: Include, not Insert

Note that this code is probably wrong:

>  procedure ex is
>  
>    use Lookup_Tables;
>  
>    hm: Map;
>  begin
>    hm.insert(To_Unbounded_String("key"), To_Unbounded_String("value"));
>  end ex;


The reason is that the 3-parameter Insert will raise Constraint_Error if
the key is already in the map.  You probably want to use Include
instead, which replaces the old value with the new value, if the key
already exists.  See above.