[boost] Preliminary submission: format3 version 0.1

From: Karl Nelson (kenelson_at_[hidden])
Date: 2002-01-31 12:28:03

Updated the submission to incorperate suggested improvements.

Changes
  * supports positional only for those to lazy to
    write "%1$s"
      cout << format("I have %1% %2%.", num_items, item_type);

  * switched __ to _p_ to meet standard.
  * moved internals to directory.
  * changed headers to hpp.
  * macrod group.
  * switched group to take by value for "hex"

Unanswered questions:

Should it try to support all of printf output options or
simply support that which iostreams allow and eat them for
compatiblity?

Should non-iostream things like truncate be affectable
by manipulators?

Does cout << format("%#010x" , complex<int>(20,21) ); mean
  A) the user wants all integers output to be show base with
     12 charactors zero padded.    0x00000016+0x00000017i
  B) The total width should be 10 with showbase and zero padding?
     0x16+0x17i
?

Should formating of int and float be in iostream instead 
Ie.
   os.float_format("##.####");
   os.int_format("0x0######",hex);
rather than the simple state machine?

Suggestions not yet incorperated.
  - Checking for too many parameters.

  - The following should silently swallow the "foo" argument:

    cout << format("%2$s", "foo", "bar");

    Right now, it invokes undefined behavior.

  - 'bad_format_string' should derive from 'std::exception'.

--Karl