IFS in RPG -- RPG400-L

This is great!  Between this and some of the other
ideas in this thread (Peter Dow, Jim Langston) I'm
getting pretty psyched!  Unfortunately this will
probably not come to pass.  It will likely be
poo-pooed by some (IBMer who shall remain nameless) as
being a waste since we can do this via API.  Well why
waste time with EXFMT when the DSM APIs will do just
fine.  In fact why not just chuck it all and go back
to assembler?  We don't need no stinking HLL!

Recently on MidrangeComputing's forum I floated the
idea of a "Move Corresponding" type operation for RPG
data structures.  This was brushed aside... even
though COBOL has had this functionality for decades.
This would be nice for loading/unloading to/from
screen and DBfile buffers (externally defined DS)...
one operation, done.

I suppose we will have to create our own SRVPGM for
this.  How about opensource but no GNU no nothing,
free to anyone with no strings?  What do you all thing
about that?

JMO -
Tom


 |  -----Original Message-----
 |  From: Buck Calabro
[mailto:Buck.Calabro@commsoft.net]
 |  Sent: Friday, July 12, 2002 13:36
 |  To: rpg400-l@midrange.com
 |  Subject: RE: IFS in RPG
 |
 |
 |  Presume that the compiler can dynamically open any
stream
 |  file we have.
 |  Presume that the compiler can use
OPEN/CLOSE/READ/WRITE and
 |  even UPDATE to
 |  change the pseudo-records size. (why not, it's my
fantasy!)
 |  Presume that the runtime has decoders for all the
popular
 |  formats, and even
 |  allows me to register a decoder for formats that
aren't
 |  (yet) included with
 |  OS/400.
 |  Presume that the compiler can dynamically call the
proper
 |  runtime decoder
 |  and throw errors when the program's receiver
 |  variable/structure/new data
 |  type can't match the decoded file at runtime.
 |  Presume that everything I said about 'decoder'
applies to
 |  'encoder' as well.
 |
 |  What did I miss.... let me see now...  Oh.
 |
 |  How do we tell the runtime what kind of file we're
looking
 |  at?  Do we want
 |  OPEN to examine the first 10kb of the file and
deduce it's
 |  proper decoder?
 |  No, that won't work... too many chances for
overlap.  Oh,
 |  wait; how about
 |  using part of the file NAME to tell us what
decoder, let's
 |  call it a file
 |  EXTENSION!  We can simply DISREGARD those Unix
people or
 |  (heaven forefend)
 |  telephone switches and other devices that don't
use Windows naming
 |  conventions.  And never mind that Microsoft use
the same
 |  extension to mean
 |  different things as well as the same INCOMPATIBLE
thing
 |  depending on version
 |  of Excel you must target.
 |
 |  Work that one out and we have a winner.
 |
 |  Would I like to be able to issue a READ against
any version
 |  of MS Excel and
 |  fetch one row and decode each column or that row
into a
 |  data structure?  Who
 |  could possibly answer no to that request?
 |
 |  Would I like to be able to dynamically shrink and
grow my
 |  HTML by simply
 |  doing a CHAIN then an UPDATE?  Um.  Yes.
 |
 |  Do I want a way to automatically transform my
switch
 |  records in any of
 |  dozens of formats AUTOMATICALLY into my own
database
 |  structure?  What a
 |  dream... no more file transformation issues.
Ever.  XML?
 |  Don't need no
 |  fancy schmancy XML parser.  Use READ.  It'll be
able to go
 |  out and fetch the
 |  appropriate XSLT, DTD or schema and run with it.
Oh, wait
 |  - are there
 |  stream files that span 'records' delimited by
CR/LF?  Icky.
 |   No matter;
 |  we'll posit a DYNAMIC record delimiter so that we
can tell
 |  each READ when to
 |  stop reading.  Glad that's fixed.  Word document
and
 |  embedded formatting?
 |  Pffft.  Have an option to simply strip out the
formatting
 |  leaving only the
 |  text behind.  EDI/multi-format physical files?
Simple as
 |  can be - we'll
 |  just add a file descriptor file to aid the
decoder/encoder,
 |  just as if we
 |  were mapping to an actual EDI program.  WRITE and
you get
 |  the PO850 and all
 |  associated elements.  Binary formatted variable
data like
 |  IOCA or 5250 data
 |  stream or switch records could be handled with a
series of
 |  linked mapping
 |  files, so that one "keyword" triggers one decoding
table,
 |  whilst another
 |  "keyword" triggers another.  Sounds like a finite
state
 |  machine to me.
 |
 |  It's a noble goal; universal file transfer.  It'll
be quite
 |  wonderful to see
 |  iSeries and RPG as the first platform to achieve
it.  Ever.
 |
 |  Submit those PMRs today and let your needs be
known.  If we
 |  don't tell the
 |  powers that be, the work will never get scheduled,
that's
 |  certain.  Until
 |  then, decoding transferred files remain firmly in
the realm
 |  of clever
 |  application programmers.
 |    --buck
 |  _______________________________________________
 |  This is the RPG programming on the AS400 / iSeries

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