Re: MOVEA -> EVAL

["Chris Rehm" <javadisciple@xxxxxxxxxxxxx>]

Phil,
    "Undefined operation?" Do you mean that you cannot assign values to
array elements in such a chain in C? If only I hadn't tossed all my C
compilers away. But, in Java it is very much defined. Expressions are
evaluated from left to right, assignments from right to left. So, array[3]
is assigned the value of 1. Clear as can be. To me. Maybe not to the guy who
updates my code.

    Now, you defend the var1 = var2 = var3 ... etc. string as being "pretty
clear." We'll forget for the moment that it is exactly that syntax I was
using. I pointed out that when I have to work on code done that way, it is
annoying and more difficult than need be. Because I need to modify a line of
code which affects far more than my variabe, var6 in my example, I run the
risk of making a mistake that will affect values I am not considering
debugging. Of course I know how to work with it, but that doesn't make his
choice any better.
    You see, what I will know when I do that is that he chose to save a few
keystrokes at the expense of maintainability. I certainly hope the rest of
his code is not so fraught with shortcuts!

Phil wrote:
>On Tue, Jun 19, 2001 at 12:53:56PM -0700, Chris Rehm wrote:
>> Consider this:
>> x=3;
>> array[x] = x = 1;
>
>This is an undefined operation in C (right up there with 'array[x] = x++'),
>and no one reasonably familiar with the language would do it.  I can't
>think of anything off the top of my head, but I would be very surprised if
>RPG were devoid of any statements whose behavior was officially undefined.
>
>> But more common, in your string of var1 = var2 = var3 = ... I have run
>> into this on occasion with dismay. That is because I am usually at that
>> point because I have to change the assignment to var6. Because the
>> original programmer took his cute little shortcut, my maintenance job is
>> peskier. So will the guy's job who must change assignments to var2 and
>> var9.
>
>I think the 'var1 = var2 = var3 = x' syntax is pretty clear.  All of the
>variables are being set to the same value (that value which is rightmost
>in the chain).  Want to set var2 to something else?  Just take it out of
>the chain and put it in a separate statement.

Chris Rehm
javadisciple@earthlink.net


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