RE: Prototyping printf()

["Richard Jackson" <richardjackson@xxxxxxxxxxxxxxxxxx>]

Barbara:

> |What I have in mind is the ability for a compiler to extract "prototype"
> |information from a module or service program, similar to the way Java can
> |extract information directly from a compiled class.  Just a dream ...

That is my vision as well - just like externally described database files.

Richard Jackson
mailto:richardjackson@richardjackson.net
http://www.richardjacksonltd.com
Voice: 1 (303) 808-8058
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> |-----Original Message-----
> |From: owner-rpg400-l@midrange.com [mailto:owner-rpg400-l@midrange.com]On
> |Behalf Of bmorris@ca.ibm.com
> |Sent: Wednesday, September 27, 2000 11:30 AM
> |To: RPG400-L@midrange.com
> |Subject: Re: Prototyping printf()
> |
> |
> |
> |>Date: Wed, 27 Sep 00 17:13:12 +1000
> |>From: "Simon Coulter" <shc@flybynight.com.au>
> |> ...
> |>I know C simplifies parameter passing by widening or promoting
> |data types
> |but it still
> |>has to check the basic data type and handle it accordingly.  I
> |see no real
> |reason why RPG
> |>couldn't do the same.  It just has more data types to handle so it has a
> |bigger case
> |>statement and it doesn't promote the data types.  The compiler knows how
> |much storage
> |>each declared variable occupies, it can't be too difficult to use that
> |information when
> |>building the argument list.  The only real difficulty is in deciding
> |whether the
> |>arguments occupy contiguous storage or not -- and to support the va_
> |macros used by
> |>printf() it should be contiguous.
> |> ...
> |
> |Simon, the problem is that RPG has too many different numeric
> |types.  What
> |should it pass for say 3.5?  RPG could adopt C's rules and only have 2
> |basic numeric type (integer and double-float), so 3.5 would be passed as
> |8F.  Or it could say that 3.5 was packed(2,1), or perhaps
> |packed(15,5), or
> |maybe packed(30,15).  Once the compiler has figured out what the passed
> |type should be, you're right: it's easy.
> |
> |By the way, for those who would like to venture into the va_list
> |territory,
> |it IS possible to call vprintf and vsprintf with a single argument list
> |(Jim Langston, I don't think it's possible to call printf this
> |way though).
> |But coding a va_list correctly is extremely difficult in RPG.  (*Much*
> |worse than doing the formatting yourself using RPG's own capability.)
> |
> |>>Perhaps someday, ILE will have "externally-described"
> |procedures, and RPG
> |
> |>Isn't that what EXTPGM accomplishes anyway?  Or did you have something
> |else in mind?
> |
> |What I have in mind is the ability for a compiler to extract "prototype"
> |information from a module or service program, similar to the way Java can
> |extract information directly from a compiled class.  Just a dream ...
> |
> |Barbara Morris
> |
> |
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