In a recent note, Skip Robinson said:
> Date: Wed, 5 Oct 2005 17:41:35 -0700
>
> For me, the primary reason for coding CLC =C'IOLQ',3(R6) is that the
> generated length of a byte instruction, unless it's explicitly coded, is
> taken from the first operand. This instruction will compare (correctly, I
> presume) four bytes of data because the first operand is four bytes long.
>
> If the operands were simply reversed, the instruction would compare only
> one byte of data.: CLC 3(R6),=C'IOLQ'
>
> So why not code CLC 3(4,R6),=C'IOLQ' ? For future maintenance, if it
> were determined that the proper string to check for is =C'IOL' , then two
> changes would be required: the literal string and the length value in the
> first operand. Although it could be argued otherwise, I don't generally see
> a good reason for redundantly carrying the same value in two places.
>
> I don't think this is about natural language influence. It's just about
> programming convention based on experience.
>
> .
> .
> .
> JO.Skip Robinson
>
> IBM Mainframe Discussion List <[log in to unmask]> wrote on 10/05/2005
> 07:06:22 AM:
>
> > In a recent note, Gerhard Postpischil said:
> >
> > > Date: Wed, 5 Oct 2005 08:59:02 -0400
> > >
> > >
> > > I'm wondering about a few things, since this does not do what you said
> > > you wanted. The code will change a job with any program name beginning
> > > with IOLQ (e.g., IOLQTEST, IOLQFAKE). If this is your intent, it would
> > > be easier to maintain as
> > > CLC =C'IOLQ',3(R6)
> > >
> > For some reason, it's very customary to code the variable on the
> > left and the constant on the right. (Does this arise from word
> > order in English sentences? Might it be otherwise for native
> > speakers of other languages?) I sometimes work with code by
> > a colleague who prefers the opposite convention. Cognitive
> > dissonance.
> >
> <snip>
>
Humph! You then <snip>ed my immediately following paragraph:
But you suggest a valid reason, here, for placing the constant
on the left.
... removing essential context and making my general agreement with
Gerhard's point ("easier to maintain") appear to be disagreement.
-- gil
--
StorageTek
INFORMATION made POWERFUL
----------------------------------------------------------------------
For IBM-MAIN subscribe / signoff / archive access instructions,
send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO
Search the archives at http://bama.ua.edu/archives/ibm-main.html
