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Path: utzoo!utgpu!attcan!uunet!lll-winken!ames!mailrus!cornell!uw-beaver!ssc-vax!shuksan!scott
From: scott@shuksan.UUCP (Scott Moody)
Newsgroups: comp.lang.ada
Subject: Re: enumeration literal/internal codes query
Summary: mixed_io
Keywords: enumeration, literal, representation
Message-ID: <1105@shuksan.UUCP>
Date: 19 Jan 89 19:44:28 GMT
References: <1494@wayback.UUCP> <1499@wayback.UUCP> <1074@shuksan.UUCP> <1438@trantor.harris-atd.com>
Organization: The Boeing Co., BAC MMST, Seattle, WA
List-Id: <comp.lang.ada>

In article <1438@trantor.harris-atd.com>, bbadger@x102c.uucp (Badger BA 64810) writes:
> In article <1074@shuksan.UUCP> scott@shuksan.UUCP (Scott Moody) writes:
> 
> I've been wondering why you *want* to access the ``internal'' representation.
> The standard use for representation clauses on enumeration types is to ``hide''
> The only thing I've thought of is to use it as an ``external representation''
> to be written to a file.  Normally, of course, you would just instantiate 
> SEQUENTIAL_IO on the enumeration type, or on a record type with a component

Try:
 type opcodes is
     ( op_no_op,
       op_integer,
       op_string,
       op_long_integer);

    for opcodes use
      (  
         op_no_op               => 16#00#,
         op_integer             => 16#41#,
         op_string              => 16#52#,
         op_long_integer        => 16#63#);

   Note the nice and clean syntax that Ada has supplied.

In my case, I am writing the internal representations 
of a lot of data structures to a file. Unfortunately 
there is no mixed_sequential_io so everything
must be broken into a common data type (unsigned bytes in my case).
Thus someone needs to make this conversion outside of the 'sequential_io' 
package. I supply a function to make this conversion which hides some
of the burden.

I agree that a sequential_io package would be nice, especially a mixed_io.

-- scott