RE: FOR op-code

Hans,

I can't read that code? Is it written is some advanced language?  <vbg>

Bob Cozzi
cozzi@rpgiv.com
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> -----Original Message-----
> From: rpg400-l-admin@midrange.com [mailto:rpg400-l-admin@midrange.com]
On
> Behalf Of boldt@ca.ibm.com
> Sent: Wednesday, December 12, 2001 8:13 AM
> To: rpg400-l@midrange.com
> Subject: Re: FOR op-code
>
> Tom wrote:
> >Second the idea about %TRIM.
>
> Your wish is my command!  Here's an RPG procedure that implements
> an extended trim operation:
>
>  //===============================================================//
>  // Procedure:  trimx                                             //
>  //---------------------------------------------------------------//
>  // Trim specified characters from string.                        //
>  //                                                               //
>  // Parameters:                                                   //
>  //    I: string   - string to trim                               //
>  //    I: chars    - list of characters to trim                   //
>  //                                                               //
>  // Returns:  trimmed string                                      //
>  //                                                               //
>  //===============================================================//
> P trimx           b
> D trimx           pi          1000a   varying
> D   string                    1000a   const varying
> D   chars                      256a   const varying
> D start           s             10i 0
>  /free
>     start = %check(chars:string);
>     if start = 0;
>        return '';
>     endif;
>     return %subst(string: start: %checkr(chars:string) - start + 1);
>  /end-free
> P trimx           e
>
> Just put the prototype into a /copy member, compile the procedure,
> and put in into a service program, and you've got your enhancement!
> (I'll leave it to you to implement "trimxl()" and "trimxr()".)
>
>
> >But since we're on the subject of
> >wish-lists...
>
> >I wish the FOR op-code did away with the TO/DOWNTO and instead looked
at
> the
> >sign of the BY increment.  There would also have to be a change in
the way
> >the limit value and the index are compared.
> >
> >So that I can fill an array 'forwards' or 'backwards', for instance.
> This
> >seems more 'natural' to me.
>
> Since that might cause existing FOR loops to behave differently,
> this isn't going to happen.  With the current syntax, it is clear
> exactly which direction the loop interates.
>
> One problem with the proposal is what happens when the sign of
> the increment variable changes during the looping?  The limit
> test would also change sense, and would likely cause the loop
> to exit earlier than expected since the index value would now
> be on the other side of the limit value.
>
> Cheers!  Hans
>
> Hans Boldt, ILE RPG Development, IBM Toronto Lab, boldt@ca.ibm.com
>
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