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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]## Re: [tlug] Code Readability (was: perl?)

- Date: Sun, 21 Aug 2016 05:16:54 +0900
From:"Stephen J. Turnbull" <turnbull.stephen.fw@example.com>Subject:Re: [tlug] Code Readability (was: perl?)- References: <22451.6786.829094.726@turnbull.sk.tsukuba.ac.jp> <20160819132402.GC30780@quadratic.cynic.net> <CADR0rnf6FfGtV6atsGGdoKPnVrsh58Ytk4LWnM=QU8MjEVgo-A@mail.gmail.com> <20160819193223.GD30780@quadratic.cynic.net>

Curt Sampson writes: > On 2016-08-19 23:42 +0900 (Fri), Benjamin Kowarsch wrote: > > With all this multi-modality, you can no longer tell for a given > > arbitrary context whether something like \( means a verbatim > > opening parenthesis or an opening group modifier symbol. It could > > be either depending on multi-modal settings and context. > > Correct. And indeed that's a PITA. But basically everything since Perl has decided that escaped punctuation is a literal. And grep is really the only multi-modal application that matters (or ever did). Personally I think that deprecation of "fgrep" and "egrep" was a mistake. > > But now imagine that the ^2 could mean either squared or factorial or some > > other operation, depending on some definition on a different page at the > > end of the current chapter in which the formula is presented. Then imagine > > that more than half the symbols in the formula would be like that, that > > they too could have different meanings depending on something that is not > > actually part of the formula. And in a different book, it could mean > > something different yet again. No two formulas in two different books > > would mean the same, even if they look the same. > > Yes. That's an excellent description of the state of mathematical notation. > > > If mathematical notation worked like that, we would still be in the > > medieval ages.... > > Yet it does work like that, and we're not. In fact, it's arguable that much progress in mathematics is due to recognizing that two notations that look similar are actually similar, and then finding out *why* they are similar and *how* they differ. I suppose sometimes it goes the other way (one notation is used for two concepts that are really different, and a notation is invented to distinguish the two), but I can't think of examples offhand. > > For this reason ISO 80001 states that... I think you mean ISO 80000, perhaps Part 1? > Actually, many mathematicians don't really have much use for > international standards on quantities and units of measurement. > Particularly the mathematicians that don't even get involved with > numbers. Definitely. As far as I can tell, mathematical notation usually standardizes on that of the most popular textbook with an adequate notation, about 100 years after research in the field stops<wink/>. This doesn't cause problems for mathematicians at all. And I've never seen a preface that says "This book conforms to ISO 80000 in notation." > > If there is a chance to interpret symbols in different ways and > > it requires cross reference checks to obtain meaning, that > > diminishes readability, regardless of brevity. > > Seems your mistake here is that you think that just because there > are multiple possible meanings when not given context, the meaning > isn't obvious in context. Well, to be fair he did write "if ... it requires cross reference checks ...". Nevertheless, I agree with you that in programming, readability is mostly a function of style, not ambiguity or redundancy (elif vs elsif vs else if, I'm looking at you!). Even for the leading example of basic vs. extended regular expressions, I just don't find myself having trouble requiring cross-referencing with any language's notation in the context of programming in that language. (I might have trouble switching from PCRE to basic RE if I didn't program in Emacs Lisp a lot. But the rule for extended RE and PCRE -- that escaped punctuation are literals, not operators, is very easy.) And in the theorem-proving side of mathematics, the cross reference checks are needed anyway -- definitions and postulates are generally presented immediately before use and their content explicitly stated in proofs. So, the analogy of programming to mathematics is bogus, except for pure computation. One could even argue that programming languages are the solution to ambiguity and redundancy in computation -- except for the fact that there are so many different languages!

References:

Re: [tlug] perl? (was: Employment for "oldies")

From:Stephen J. Turnbull[tlug] Code Readability (was: perl?)

From:Curt SampsonRe: [tlug] Code Readability (was: perl?)

From:Benjamin KowarschRe: [tlug] Code Readability (was: perl?)

From:Curt Sampson

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