I think if you step back, you can ask what the purpose of an error message is and who designs it.
Is the message for the developer or others on their team or something an end-user knowing nothing about R will see. This reminds me a bit of legal mumbo jumbo that turns many reading it off as it keeps talking about the party of the first part or the plaintiff as compared to somewhat straighter talk. The scenario is that you are comparing two things. Their names are not things like "target" or "current" so even other programmers not involved in your code will pause and wonder. One view is to use phrases like first and second arguments/lists/whatever. You might talk about the one on the left (but using LHS is a bit opaque) versus the one on the right. But sometimes it can be too verbose. Sometimes the error message is being generated not where everything is clear. So ideally you could say: WARNING Danger Will Robinson. Comparing two things for equality. Result finds mismatches. There were NA found on the (left or right) that were not matched on the other side. Number of such found: 2 If you had a Systems Engineer write detailed requirements that included something a bit better than the example and the programmer was able to supply the data using the words and guidelines, it might fit some needs but maybe not satisfy other programmers. But there are human factors people whose job it is to help choose among alternatives and although they may not choose well, letting a programmer come up with whatever they feel like is generally worse. Yes, in their microcosm centered on a dozen lines of code, "current" and "target" may have meaning. But are they the intended user of the product? -----Original Message----- From: R-devel <r-devel-boun...@r-project.org> On Behalf Of Antoine Fabri Sent: Thursday, March 2, 2023 12:23 PM To: peter dalgaard <pda...@gmail.com> Cc: R-devel <r-devel@r-project.org> Subject: Re: [Rd] confusing all.equal output Good points. I don't mind the terminology since target and current are the names of the arguments. As the function is already designed to stop at the first failing check we might not need to enumerate or count the mismatches, instead we could have "`NA` found in `target` but not in `current` at position <FIRST_MISMATCH>" [[alternative HTML version deleted]] ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel