Re: RPG read loops

[James Rich <james@xxxxxxxxxxx>]

On Tue, 1 Feb 2005, Tony Carolla wrote:

> > DoW readmyfile();
> > EndDo;
>
> So each file would have it's own subprocedure for reading?  Beautiful.
> Bulky, but beautiful.  And if you wanted to read into a DS, then
> would you define the DS in the subproc and the main, and return the
> DS?  Or would you forego encapsulation and access the Global DS?  And
> then, while maintaining this code, you might find yourself scrolling
> all the way down to the bottom/back to the top,etc.
>
> In my opinion, this overcomplicates the operation.

That's why an earlier post mentioned that it would be nice to be able to 
pass a handle (a pointer to an open file) and use that for the read.  Then 
one subprocedure could read any file.  Psuedo-code follows:

eval filehandle = %open(myfile);

dow (readfile(filehandle) <> %EOF)
...

P readfile    B
D readfile    PR
D filepointer          *
C            read   filepointer
      return %EOF;
P readfile    E

This could read any file at all.  This is essentially the way C works. 
The I/O functions in C take a pointer to a file as an argument, enabling 
them to read a file without knowing the file name.

There's no reason why a read implemented this way couldn't put the results 
into a DS or even from a DS.  Having a %read that worked this way would 
not take anything from the way read works now.

James Rich

It's not the software that's free; it's you.
        - billyskank on Groklaw