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From: xorque <xorquewasp@googlemail.com>
Newsgroups: comp.lang.ada
Subject: Generalized serialization for enumeration types
Date: Wed, 26 Aug 2009 03:22:08 -0700 (PDT)
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Date: 2009-08-26T03:22:08-07:00
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Hello.

I'm designing a package that uses a lot of similar but distinct
enumeration types.

At some point, those types need to be encoded to be sent over
the wire. The encoding rules are simple:

  The enumeration values are converted to unsigned 32 bit
  integers with the first value as 0 and increasing sequentially
  with each new value. The 32 bit value is packed into big-endian
  byte order.

The problem is: With so many enumeration types, I now have about 300
lines of almost identical procedures (to be used as stream attributes)
that just call a procedure that packs Unsigned_32 values into
Storage_Element arrays.

Is there some clever way I can just write ONE 'Write attribute
procedure
and ONE 'Read attribute procedure and have all the defined enumeration
types use those?

Freezing rules prevented me from writing a generic
Packed_Enumeration_IO
package ("representation item appears too late").