Re: idempotent (was Re: exif --remove not idempotent, and a Debian man page bug)

[rhkramer@gmail.com]

On Sunday, September 25, 2022 08:42:57 AM The Wanderer wrote:
> On 2022-09-25 at 08:22, rhkramer@gmail.com wrote:
> > Oops, ignore that previous response ...
> > 
> > On second thought, what hede wrote is correct, it is just stated in a
> > way that I wasn't famiiar with (and I haven't had my morning coffee
> > yet)
> 
> Are you sure?

No ;-)

I'm sure that what I wrote is correct (e.g., as simple examples, 
multiplication by 1 or addition of 0), and I'm sure what you wrote (below) is 
correct, but I had trouble interpreting Hede's words, and eventually decided 
that maybe what he said is equivalent but using different words.

I'm not going to go back and look at his words again atm, but even if they are 
correct, I don't like them, it is too difficult (for me ;-) to interpret them / 
read them as equivalent to other (correct) definitions of idempotent (like 
yours, mine, Wikipedia's, and others that have been mentioned on the list). 

I'm debating whether this is worth sending this to the list or if will just 
contribute to the noise (and somehow "justify" my two previous responses) -- I 
wrote it so I'll probably send it, although I could instead send it just to 
you (The Wanderer).

Sending to the list.

> 
> Because it doesn't seem to match my understanding of the meaning of the
> word, and what you gave as an alternative seems closer.
> 
> 
> If I had to describe the concept of idempotence, I might choose
> something like:
> 
> Take object A.
> 
> Apply it as input to operation O, and get object B as output.
> 
> Take object B, apply it as input to operation O, and get object C as
> output.
> 
> If the nature of operation O is such that objects B and C are guaranteed
> to always be identical, no matter what object A was, then operation O is
> categorized as being idempotent.
> 
> 
> That's not producing the same output with the same input (which is how I
> read the explanation that hede gave); that's producing the same output
> with both the original input *and* the output obtained by processing
> that original input.
> 
> 
> The definitions found in foldoc and in the Jargon File seem compatible
> with that.

-- 
rhk

If you reply: snip, snip, and snip again; leave attributions; avoid HTML; 
avoid top posting; and keep it "on list".  (Oxford comma included at no 
charge.)  If you change topics, change the Subject: line. 

Writing is often meant for others to read and understand (legal agreements 
excepted?) -- make it easier for your reader by various means, including 
liberal use of whitespace and minimal use of (obscure?) jargon, abbreviations, 
acronyms, and references.

If someone else has already responded to a question, decide whether any 
response you add will be helpful or not ...

A picture is worth a thousand words -- divide by 10 for each minute of video 
(or audio) or create a transcript and edit it to 10% of the original.