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javascript - What is the purpose of double curly braces in React's JSX syntax? - Stack Overflow
The exterior set of curly braces are letting JSX know you want a JS expression. The interior set of curly braces represent a JavaScript object, meaning you’re passing in an object to the style attribute.
q-n-a  stackex  programming  explanation  trivia  gotchas  syntax  javascript  frontend  DSL  intricacy  facebook  libraries  frameworks 
october 2019 by nhaliday
What does it mean when a CSS rule is grayed out in Chrome's element inspector? - Stack Overflow
It seems that a strike-through indicates that a rule was overridden, but what does it mean when a style is grayed out?

--

Greyed/dimmed out text, can mean either

1. it's a default rule/property the browser applies, which includes defaulted short-hand properties.
2. It involves inheritance which is a bit more complicated.

...

In the case where a rule is applied to the currently selected element due to inheritance (i.e. the rule was applied to an ancestor, and the selected element inherited it), chrome will again display the entire ruleset.

The rules which are applied to the currently selected element appear in normal text.

If a rule exists in that set but is not applied because it's a non-inheritable property (e.g. background color), it will appear as greyed/dimmed text.

https://stackoverflow.com/questions/34712218/what-does-it-mean-when-chrome-dev-tools-shows-a-computed-property-greyed-out
Please note, not the Styles panel (I know what greyed-out means in that context—not applied), but the next panel over, the Computed properties panel.
--
The gray calculated properties are neither default, nor inherited. This only occurs on properties that were not defined for the element, but _calculated_ from either its children or parent _based on runtime layout rendering_.

Take this simple page as an example, display is default and font-size is inherited:
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october 2019 by nhaliday
Codepip | Learn to code by playing games
I don't really like frontend stuff tbh so this kind of stuff might be path of least resistance to me learning it
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october 2019 by nhaliday
When to use margin vs padding in CSS - Stack Overflow
TL;DR: By default I use margin everywhere, except when I have a border or background and want to increase the space inside that visible box.

To me, the biggest difference between padding and margin is that vertical margins auto-collapse, and padding doesn't.

https://stackoverflow.com/questions/5958699/difference-between-margin-and-padding
One key thing that is missing in the answers here:

Top/Bottom margins are collapsible.

So if you have a 20px margin at the bottom of an element and a 30px margin at the top of the next element, the margin between the two elements will be 30px rather than 50px. This does not apply to left/right margin or padding.
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Note that there are very specific circumstances in which vertical margins collapse - not just any two vertical margins will do so. Which just makes it all the more confusing (unless you're very familiar with the box model).

[ed.: roughly, separation = padding(A) + padding(B) + max{margin(A), margin(B)}, border in between padding and margin]
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october 2019 by nhaliday
Ask HN: Learning modern web design and CSS | Hacker News
Ask HN: Best way to learn HTML and CSS for web design?: https://news.ycombinator.com/item?id=11048409
Ask HN: How to learn design as a hacker?: https://news.ycombinator.com/item?id=8182084

Ask HN: How to learn front-end beyond the basics?: https://news.ycombinator.com/item?id=19468043
Ask HN: What is the best JavaScript stack for a beginner to learn?: https://news.ycombinator.com/item?id=8780385
Free resources for learning full-stack web development: https://news.ycombinator.com/item?id=13890114

Ask HN: What is essential reading for learning modern web development?: https://news.ycombinator.com/item?id=14888251
Ask HN: A Syllabus for Modern Web Development?: https://news.ycombinator.com/item?id=2184645

Ask HN: Modern day web development for someone who last did it 15 years ago: https://news.ycombinator.com/item?id=20656411
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october 2019 by nhaliday
Learn to speak vim — verbs, nouns, and modifiers! - Yan Pritzker
learn some verbs: v (visual), c (change), d (delete), y (yank/copy). these are the most important. there are others
learn some modifiers: i (inside), a (around), t (till..finds a character), f (find..like till except including the char), / (search..find a string/regex)
learn some text objects: w (word), s (sentence) p (paragraph) b (block/parentheses), t (tag, works for html/xml) there are others
techtariat  howto  objektbuch  top-n  list  editors  composition-decomposition  DSL  lexical  atoms  yak-shaving  language 
august 2019 by nhaliday
selenium - What is the difference between cssSelector & Xpath and which is better with respect to performance for cross browser testing? - Stack Overflow
CSS selectors perform far better than Xpath and it is well documented in Selenium community. Here are some reasons,
- Xpath engines are different in each browser, hence make them inconsistent
- IE does not have a native xpath engine, therefore selenium injects its own xpath engine for compatibility of its API. Hence we lose the advantage of using native browser features that WebDriver inherently promotes.
- Xpath tend to become complex and hence make hard to read in my opinion
However there are some situations where, you need to use xpath, for example, searching for a parent element or searching element by its text (I wouldn't recommend the later).
--
I’m going to hold the unpopular on SO selenium tag opinion that XPath is preferable to CSS in the longer run.

This long post has two sections - first I'll put a back-of-the-napkin proof the performance difference between the two is 0.1-0.3 milliseconds (yes; that's 100 microseconds), and then I'll share my opinion why XPath is more powerful.

...

With the performance out of the picture, why do I think xpath is better? Simple – versatility, and power.

Xpath is a language developed for working with XML documents; as such, it allows for much more powerful constructs than css.
For example, navigation in every direction in the tree – find an element, then go to its grandparent and search for a child of it having certain properties.
It allows embedded boolean conditions – cond1 and not(cond2 or not(cond3 and cond4)); embedded selectors – "find a div having these children with these attributes, and then navigate according to it".
XPath allows searching based on a node's value (its text) – however frowned upon this practice is, it does come in handy especially in badly structured documents (no definite attributes to step on, like dynamic ids and classes - locate the element by its text content).

The stepping in css is definitely easier – one can start writing selectors in a matter of minutes; but after a couple of days of usage, the power and possibilities xpath has quickly overcomes css.
And purely subjective – a complex css is much harder to read than a complex xpath expression.
q-n-a  stackex  comparison  best-practices  programming  yak-shaving  python  javascript  web  frontend  performance  DSL  debate  grokkability  trees  grokkability-clarity 
august 2019 by nhaliday
The Compositional Nature of Vim - Ismail Badawi
https://medium.com/@mkozlows/why-atom-cant-replace-vim-433852f4b4d1
1976 was a good year for text editors. At MIT, Richard Stallman and Guy Steele wrote the first version of Emacs. And over at Berkeley, Bill Joy wrote vi (though it wouldn’t be called that for a few years yet).
It’s reductionist to say that these two editors were each built around one big idea, but what the hell, let’s be reductionist. Because what stands out today, looking at modern editors like Sublime Text and Atom, is how Emacs’ big idea has been thoroughly learned — and how vi’s big idea hasn’t.

Emacs and Extensibility
Vi and Composability
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august 2019 by nhaliday
The Existential Risk of Math Errors - Gwern.net
How big is this upper bound? Mathematicians have often made errors in proofs. But it’s rarer for ideas to be accepted for a long time and then rejected. But we can divide errors into 2 basic cases corresponding to type I and type II errors:

1. Mistakes where the theorem is still true, but the proof was incorrect (type I)
2. Mistakes where the theorem was false, and the proof was also necessarily incorrect (type II)

Before someone comes up with a final answer, a mathematician may have many levels of intuition in formulating & working on the problem, but we’ll consider the final end-product where the mathematician feels satisfied that he has solved it. Case 1 is perhaps the most common case, with innumerable examples; this is sometimes due to mistakes in the proof that anyone would accept is a mistake, but many of these cases are due to changing standards of proof. For example, when David Hilbert discovered errors in Euclid’s proofs which no one noticed before, the theorems were still true, and the gaps more due to Hilbert being a modern mathematician thinking in terms of formal systems (which of course Euclid did not think in). (David Hilbert himself turns out to be a useful example of the other kind of error: his famous list of 23 problems was accompanied by definite opinions on the outcome of each problem and sometimes timings, several of which were wrong or questionable5.) Similarly, early calculus used ‘infinitesimals’ which were sometimes treated as being 0 and sometimes treated as an indefinitely small non-zero number; this was incoherent and strictly speaking, practically all of the calculus results were wrong because they relied on an incoherent concept - but of course the results were some of the greatest mathematical work ever conducted6 and when later mathematicians put calculus on a more rigorous footing, they immediately re-derived those results (sometimes with important qualifications), and doubtless as modern math evolves other fields have sometimes needed to go back and clean up the foundations and will in the future.7

...

Isaac Newton, incidentally, gave two proofs of the same solution to a problem in probability, one via enumeration and the other more abstract; the enumeration was correct, but the other proof totally wrong and this was not noticed for a long time, leading Stigler to remark:

...

TYPE I > TYPE II?
“Lefschetz was a purely intuitive mathematician. It was said of him that he had never given a completely correct proof, but had never made a wrong guess either.”
- Gian-Carlo Rota13

Case 2 is disturbing, since it is a case in which we wind up with false beliefs and also false beliefs about our beliefs (we no longer know that we don’t know). Case 2 could lead to extinction.

...

Except, errors do not seem to be evenly & randomly distributed between case 1 and case 2. There seem to be far more case 1s than case 2s, as already mentioned in the early calculus example: far more than 50% of the early calculus results were correct when checked more rigorously. Richard Hamming attributes to Ralph Boas a comment that while editing Mathematical Reviews that “of the new results in the papers reviewed most are true but the corresponding proofs are perhaps half the time plain wrong”.

...

Gian-Carlo Rota gives us an example with Hilbert:

...

Olga labored for three years; it turned out that all mistakes could be corrected without any major changes in the statement of the theorems. There was one exception, a paper Hilbert wrote in his old age, which could not be fixed; it was a purported proof of the continuum hypothesis, you will find it in a volume of the Mathematische Annalen of the early thirties.

...

Leslie Lamport advocates for machine-checked proofs and a more rigorous style of proofs similar to natural deduction, noting a mathematician acquaintance guesses at a broad error rate of 1/329 and that he routinely found mistakes in his own proofs and, worse, believed false conjectures30.

[more on these "structured proofs":
https://academia.stackexchange.com/questions/52435/does-anyone-actually-publish-structured-proofs
https://mathoverflow.net/questions/35727/community-experiences-writing-lamports-structured-proofs
]

We can probably add software to that list: early software engineering work found that, dismayingly, bug rates seem to be simply a function of lines of code, and one would expect diseconomies of scale. So one would expect that in going from the ~4,000 lines of code of the Microsoft DOS operating system kernel to the ~50,000,000 lines of code in Windows Server 2003 (with full systems of applications and libraries being even larger: the comprehensive Debian repository in 2007 contained ~323,551,126 lines of code) that the number of active bugs at any time would be… fairly large. Mathematical software is hopefully better, but practitioners still run into issues (eg Durán et al 2014, Fonseca et al 2017) and I don’t know of any research pinning down how buggy key mathematical systems like Mathematica are or how much published mathematics may be erroneous due to bugs. This general problem led to predictions of doom and spurred much research into automated proof-checking, static analysis, and functional languages31.

[related:
https://mathoverflow.net/questions/11517/computer-algebra-errors
I don't know any interesting bugs in symbolic algebra packages but I know a true, enlightening and entertaining story about something that looked like a bug but wasn't.

Define sinc𝑥=(sin𝑥)/𝑥.

Someone found the following result in an algebra package: ∫∞0𝑑𝑥sinc𝑥=𝜋/2
They then found the following results:

...

So of course when they got:

∫∞0𝑑𝑥sinc𝑥sinc(𝑥/3)sinc(𝑥/5)⋯sinc(𝑥/15)=(467807924713440738696537864469/935615849440640907310521750000)𝜋

hmm:
Which means that nobody knows Fourier analysis nowdays. Very sad and discouraging story... – fedja Jan 29 '10 at 18:47

--

Because the most popular systems are all commercial, they tend to guard their bug database rather closely -- making them public would seriously cut their sales. For example, for the open source project Sage (which is quite young), you can get a list of all the known bugs from this page. 1582 known issues on Feb.16th 2010 (which includes feature requests, problems with documentation, etc).

That is an order of magnitude less than the commercial systems. And it's not because it is better, it is because it is younger and smaller. It might be better, but until SAGE does a lot of analysis (about 40% of CAS bugs are there) and a fancy user interface (another 40%), it is too hard to compare.

I once ran a graduate course whose core topic was studying the fundamental disconnect between the algebraic nature of CAS and the analytic nature of the what it is mostly used for. There are issues of logic -- CASes work more or less in an intensional logic, while most of analysis is stated in a purely extensional fashion. There is no well-defined 'denotational semantics' for expressions-as-functions, which strongly contributes to the deeper bugs in CASes.]

...

Should such widely-believed conjectures as P≠NP or the Riemann hypothesis turn out be false, then because they are assumed by so many existing proofs, a far larger math holocaust would ensue38 - and our previous estimates of error rates will turn out to have been substantial underestimates. But it may be a cloud with a silver lining, if it doesn’t come at a time of danger.

https://mathoverflow.net/questions/338607/why-doesnt-mathematics-collapse-down-even-though-humans-quite-often-make-mista

more on formal methods in programming:
https://www.quantamagazine.org/formal-verification-creates-hacker-proof-code-20160920/
https://intelligence.org/2014/03/02/bob-constable/

https://softwareengineering.stackexchange.com/questions/375342/what-are-the-barriers-that-prevent-widespread-adoption-of-formal-methods
Update: measured effort
In the October 2018 issue of Communications of the ACM there is an interesting article about Formally verified software in the real world with some estimates of the effort.

Interestingly (based on OS development for military equipment), it seems that producing formally proved software requires 3.3 times more effort than with traditional engineering techniques. So it's really costly.

On the other hand, it requires 2.3 times less effort to get high security software this way than with traditionally engineered software if you add the effort to make such software certified at a high security level (EAL 7). So if you have high reliability or security requirements there is definitively a business case for going formal.

WHY DON'T PEOPLE USE FORMAL METHODS?: https://www.hillelwayne.com/post/why-dont-people-use-formal-methods/
You can see examples of how all of these look at Let’s Prove Leftpad. HOL4 and Isabelle are good examples of “independent theorem” specs, SPARK and Dafny have “embedded assertion” specs, and Coq and Agda have “dependent type” specs.6

If you squint a bit it looks like these three forms of code spec map to the three main domains of automated correctness checking: tests, contracts, and types. This is not a coincidence. Correctness is a spectrum, and formal verification is one extreme of that spectrum. As we reduce the rigour (and effort) of our verification we get simpler and narrower checks, whether that means limiting the explored state space, using weaker types, or pushing verification to the runtime. Any means of total specification then becomes a means of partial specification, and vice versa: many consider Cleanroom a formal verification technique, which primarily works by pushing code review far beyond what’s humanly possible.

...

The question, then: “is 90/95/99% correct significantly cheaper than 100% correct?” The answer is very yes. We all are comfortable saying that a codebase we’ve well-tested and well-typed is mostly correct modulo a few fixes in prod, and we’re even writing more than four lines of code a day. In fact, the vast… [more]
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july 2019 by nhaliday
Integrated vs type based shrinking - Hypothesis
The big difference is whether shrinking is integrated into generation.

In Haskell’s QuickCheck, shrinking is defined based on types: Any value of a given type shrinks the same way, regardless of how it is generated. In Hypothesis, test.check, etc. instead shrinking is part of the generation, and the generator controls how the values it produces shrinks (this works differently in Hypothesis and test.check, and probably differently again in EQC, but the user visible result is largely the same)

This is not a trivial distinction. Integrating shrinking into generation has two large benefits:
- Shrinking composes nicely, and you can shrink anything you can generate regardless of whether there is a defined shrinker for the type produced.
- You can _guarantee that shrinking satisfies the same invariants as generation_.
The first is mostly important from a convenience point of view: Although there are some things it let you do that you can’t do in the type based approach, they’re mostly of secondary importance. It largely just saves you from the effort of having to write your own shrinkers.

But the second is really important, because the lack of it makes your test failures potentially extremely confusing.

...

[example: even_numbers = integers().map(lambda x: x * 2)]

...

In this example the problem was relatively obvious and so easy to work around, but as your invariants get more implicit and subtle it becomes really problematic: In Hypothesis it’s easy and convenient to generate quite complex data, and trying to recreate the invariants that are automatically satisfied with that in your tests and/or your custom shrinkers would quickly become a nightmare.

I don’t think it’s an accident that the main systems to get this right are in dynamic languages. It’s certainly not essential - the original proposal that lead to the implementation for test.check was for Haskell, and Jack is an alternative property based system for Haskell that does this - but you feel the pain much more quickly in dynamic languages because the typical workaround for this problem in Haskell is to define a newtype, which lets you turn off the default shrinking for your types and possibly define your own.

But that’s a workaround for a problem that shouldn’t be there in the first place, and using it will still result in your having to encode the invariants into your your shrinkers, which is more work and more brittle than just having it work automatically.

So although (as far as I know) none of the currently popular property based testing systems for statically typed languages implement this behaviour correctly, they absolutely can and they absolutely should. It will improve users’ lives significantly.

https://hypothesis.works/articles/compositional-shrinking/
In my last article about shrinking, I discussed the problems with basing shrinking on the type of the values to be shrunk.

In writing it though I forgot that there was a halfway house which is also somewhat bad (but significantly less so) that you see in a couple of implementations.

This is when the shrinking is not type based, but still follows the classic shrinking API that takes a value and returns a lazy list of shrinks of that value. Examples of libraries that do this are theft and QuickTheories.

This works reasonably well and solves the major problems with type directed shrinking, but it’s still somewhat fragile and importantly does not compose nearly as well as the approaches that Hypothesis or test.check take.

Ideally, as well as not being based on the types of the values being generated, shrinking should not be based on the actual values generated at all.

This may seem counter-intuitive, but it actually works pretty well.

...

We took a strategy and composed it with a function mapping over the values that that strategy produced to get a new strategy.

Suppose the Hypothesis strategy implementation looked something like the following:
...
i.e. we can generate a value and we can shrink a value that we’ve previously generated. By default we don’t know how to generate values (subclasses have to implement that) and we can’t shrink anything, which subclasses are able to fix if they want or leave as is if they’re fine with that.

(This is in fact how a very early implementation of it looked)

This is essentially the approach taken by theft or QuickTheories, and the problem with it is that under this implementation the ‘map’ function we used above is impossible to define in a way that preserves shrinking: In order to shrink a generated value, you need some way to invert the function you’re composing with (which is in general impossible even if your language somehow exposed the facilities to do it, which it almost certainly doesn’t) so you could take the generated value, map it back to the value that produced it, shrink that and then compose with the mapping function.

...

The key idea for fixing this is as follows: In order to shrink outputs it almost always suffices to shrink inputs. Although in theory you can get functions where simpler input leads to more complicated output, in practice this seems to be rare enough that it’s OK to just shrug and accept more complicated test output in those cases.

Given that, the _way to shrink the output of a mapped strategy is to just shrink the value generated from the first strategy and feed it to the mapping function_.

Which means that you need an API that can support that sort of shrinking.

https://hypothesis.works/articles/types-and-properties/
This happens a lot: Frequently there are properties that only hold in some restricted domain, and so you want more specific tests for that domain to complement your other tests for the larger range of data.

When this happens you need tools to generate something more specific, and those requirements don’t map naturally to types.

[ed.: Some examples of how this idea can be useful:
Have a type but want to test different distributions on it for different purposes. Eg, comparing worst-case and average-case guarantees for benchmarking time/memory complexity. Comparing a slow and fast implementation on small input sizes, then running some sanity checks for the fast implementation on large input sizes beyond what the slow implementation can handle.]

...

In Haskell, traditionally we would fix this with a newtype declaration which wraps the type. We could find a newtype NonEmptyList and a newtype FiniteFloat and then say that we actually wanted a NonEmptyList[FiniteFloat] there.

...

But why should we bother? Especially if we’re only using these in one test, we’re not actually interested in these types at all, and it just adds a whole bunch of syntactic noise when you could just pass the data generators directly. Defining new types for the data you want to generate is purely a workaround for a limitation of the API.

If you were working in a dependently typed language where you could already naturally express this in the type system it might be OK (I don’t have any direct experience of working in type systems that strong), but I’m sceptical of being able to make it work well - you’re unlikely to be able to automatically derive data generators in the general case, because the needs of data generation “go in the opposite direction” from types (a type is effectively a predicate which consumes a value, where a data generator is a function that produces a value, so in order to produce a generator for a type automatically you need to basically invert the predicate). I suspect most approaches here will leave you with a bunch of sharp edges, but I would be interested to see experiments in this direction.

https://www.reddit.com/r/haskell/comments/646k3d/ann_hedgehog_property_testing/dg1485c/
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july 2019 by nhaliday
Regex cheatsheet
Many programs use regular expression to find & replace text. However, they tend to come with their own different flavor.

You can probably expect most modern software and programming languages to be using some variation of the Perl flavor, "PCRE"; however command-line tools (grep, less, ...) will often use the POSIX flavor (sometimes with an extended variant, e.g. egrep or sed -r). ViM also comes with its own syntax (a superset of what Vi accepts).

This cheatsheet lists the respective syntax of each flavor, and the software that uses it.

accidental complexity galore
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june 2019 by nhaliday
The End of the Editor Wars » Linux Magazine
Moreover, even if you assume a broad margin of error, the pollings aren't even close. With all the various text editors available today, Vi and Vim continue to be the choice of over a third of users, while Emacs well back in the pack, no longer a competitor for the most popular text editor.

https://www.quora.com/Are-there-more-Emacs-or-Vim-users
I believe Vim is actually more popular, but it's hard to find any real data on it. The best source I've seen is the annual StackOverflow developer survey where 15.2% of developers used Vim compared to a mere 3.2% for Emacs.

Oddly enough, the report noted that "Data scientists and machine learning developers are about 3 times more likely to use Emacs than any other type of developer," which is not necessarily what I would have expected.

[ed. NB: Vim still dominates overall.]

https://pinboard.in/u:nhaliday/b:6adc1b1ef4dc

Time To End The vi/Emacs Debate: https://cacm.acm.org/blogs/blog-cacm/226034-time-to-end-the-vi-emacs-debate/fulltext

Vim, Emacs and their forever war. Does it even matter any more?: https://blog.sourcerer.io/vim-emacs-and-their-forever-war-does-it-even-matter-any-more-697b1322d510
Like an episode of “Silicon Valley”, a discussion of Emacs vs. Vim used to have a polarizing effect that would guarantee a stimulating conversation, regardless of an engineer’s actual alignment. But nowadays, diehard Emacs and Vim users are getting much harder to find. Maybe I’m in the wrong orbit, but looking around today, I see that engineers are equally or even more likely to choose any one of a number of great (for any given definition of ‘great’) modern editors or IDEs such as Sublime Text, Visual Studio Code, Atom, IntelliJ (… or one of its siblings), Brackets, Visual Studio or Xcode, to name a few. It’s not surprising really — many top engineers weren’t even born when these editors were at version 1.0, and GUIs (for better or worse) hadn’t been invented.

...

… both forums have high traffic and up-to-the-minute comment and discussion threads. Some of the available statistics paint a reasonably healthy picture — Stackoverflow’s 2016 developer survey ranks Vim 4th out of 24 with 26.1% of respondents in the development environments category claiming to use it. Emacs came 15th with 5.2%. In combination, over 30% is, actually, quite impressive considering they’ve been around for several decades.

What’s odd, however, is that if you ask someone — say a random developer — to express a preference, the likelihood is that they will favor for one or the other even if they have used neither in anger. Maybe the meme has spread so widely that all responses are now predominantly ritualistic, and represent something more fundamental than peoples’ mere preference for an editor? There’s a rather obvious political hypothesis waiting to be made — that Emacs is the leftist, socialist, centralized state, while Vim represents the right and the free market, specialization and capitalism red in tooth and claw.

How is Emacs/Vim used in companies like Google, Facebook, or Quora? Are there any libraries or tools they share in public?: https://www.quora.com/How-is-Emacs-Vim-used-in-companies-like-Google-Facebook-or-Quora-Are-there-any-libraries-or-tools-they-share-in-public
In Google there's a fair amount of vim and emacs. I would say at least every other engineer uses one or another.

Among Software Engineers, emacs seems to be more popular, about 2:1. Among Site Reliability Engineers, vim is more popular, about 9:1.
--
People use both at Facebook, with (in my opinion) slightly better tooling for Emacs than Vim. We share a master.emacs and master.vimrc file, which contains the bare essentials (like syntactic highlighting for the Hack language). We also share a Ctags file that's updated nightly with a cron script.

Beyond the essentials, there's a group for Emacs users at Facebook that provides tips, tricks, and major-modes created by people at Facebook. That's where Adam Hupp first developed his excellent mural-mode (ahupp/mural), which does for Ctags what iDo did for file finding and buffer switching.
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For emacs, it was very informal at Google. There wasn't a huge community of Emacs users at Google, so there wasn't much more than a wiki and a couple language styles matching Google's style guides.

https://trends.google.com/trends/explore?date=all&geo=US&q=%2Fm%2F07zh7,%2Fm%2F01yp0m

https://www.quora.com/Why-is-interest-in-Emacs-dropping
And it is still that. It’s just that emacs is no longer unique, and neither is Lisp.

Dynamically typed scripting languages with garbage collection are a dime a dozen now. Anybody in their right mind developing an extensible text editor today would just use python, ruby, lua, or JavaScript as the extension language and get all the power of Lisp combined with vibrant user communities and millions of lines of ready-made libraries that Stallman and Steele could only dream of in the 70s.

In fact, in many ways emacs and elisp have fallen behind: 40 years after Lambda, the Ultimate Imperative, elisp is still dynamically scoped, and it still doesn’t support multithreading — when I try to use dired to list the files on a slow NFS mount, the entire editor hangs just as thoroughly as it might have in the 1980s. And when I say “doesn’t support multithreading,” I don’t mean there is some other clever trick for continuing to do work while waiting on a system call, like asynchronous callbacks or something. There’s start-process which forks a whole new process, and that’s about it. It’s a concurrency model straight out of 1980s UNIX land.

But being essentially just a decent text editor has robbed emacs of much of its competitive advantage. In a world where every developer tool is scriptable with languages and libraries an order of magnitude more powerful than cranky old elisp, the reason to use emacs is not that it lets a programmer hit a button and evaluate the current expression interactively (which must have been absolutely amazing at one point in the past).

https://www.reddit.com/r/emacs/comments/bh5kk7/why_do_many_new_users_still_prefer_vim_over_emacs/

more general comparison, not just popularity:
Differences between Emacs and Vim: https://stackoverflow.com/questions/1430164/differences-between-Emacs-and-vim

https://www.reddit.com/r/emacs/comments/9hen7z/what_are_the_benefits_of_emacs_over_vim/

https://unix.stackexchange.com/questions/986/what-are-the-pros-and-cons-of-vim-and-emacs

https://www.quora.com/Why-is-Vim-the-programmers-favorite-editor
- Adrien Lucas Ecoffet,

Because it is hard to use. Really.

However, the second part of this sentence applies to just about every good editor out there: if you really learn Sublime Text, you will become super productive. If you really learn Emacs, you will become super productive. If you really learn Visual Studio… you get the idea.

Here’s the thing though, you never actually need to really learn your text editor… Unless you use vim.

...

For many people new to programming, this is the first time they have been a power user of… well, anything! And because they’ve been told how great Vim is, many of them will keep at it and actually become productive, not because Vim is particularly more productive than any other editor, but because it didn’t provide them with a way to not be productive.

They then go on to tell their friends how great Vim is, and their friends go on to become power users and tell their friends in turn, and so forth. All these people believe they became productive because they changed their text editor. Little do they realize that they became productive because their text editor changed them[1].

This is in no way a criticism of Vim. I myself was a beneficiary of such a phenomenon when I learned to type using the Dvorak layout: at that time, I believed that Dvorak would help you type faster. Now I realize the evidence is mixed and that Dvorak might not be much better than Qwerty. However, learning Dvorak forced me to develop good typing habits because I could no longer rely on looking at my keyboard (since I was still using a Qwerty physical keyboard), and this has made me a much more productive typist.

Technical Interview Performance by Editor/OS/Language: https://triplebyte.com/blog/technical-interview-performance-by-editor-os-language
[ed.: I'm guessing this is confounded to all hell.]

The #1 most common editor we see used in interviews is Sublime Text, with Vim close behind.

Emacs represents a fairly small market share today at just about a quarter the userbase of Vim in our interviews. This nicely matches the 4:1 ratio of Google Search Trends for the two editors.

...

Vim takes the prize here, but PyCharm and Emacs are close behind. We’ve found that users of these editors tend to pass our interview at an above-average rate.

On the other end of the spectrum is Eclipse: it appears that someone using either Vim or Emacs is more than twice as likely to pass our technical interview as an Eclipse user.

...

In this case, we find that the average Ruby, Swift, and C# users tend to be stronger, with Python and Javascript in the middle of the pack.

...

Here’s what happens after we select engineers to work with and send them to onsites:

[Python does best.]

There are no wild outliers here, but let’s look at the C++ segment. While C++ programmers have the most challenging time passing Triplebyte’s technical interview on average, the ones we choose to work with tend to have a relatively easier time getting offers at each onsite.

The Rise of Microsoft Visual Studio Code: https://triplebyte.com/blog/editor-report-the-rise-of-visual-studio-code
This chart shows the rates at which each editor's users pass our interview compared to the mean pass rate for all candidates. First, notice the preeminence of Emacs and Vim! Engineers who use these editors pass our interview at significantly higher rates than other engineers. And the effect size is not small. Emacs users pass our interview at a rate 50… [more]
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june 2019 by nhaliday
package writing - Where do I start LaTeX programming? - TeX - LaTeX Stack Exchange
I think there are three categories which need to be mastered (perhaps not all in the same degree) in order to become comfortable around TeX programming:

1. TeX programming. That's very basic, it deals with expansion control, counters, scopes, basic looping constructs and so on.

2. TeX typesetting. That's on a higher level, it includes control over boxes, lines, glues, modes, and perhaps about 1000 parameters.

3. Macro packages like LaTeX.
q-n-a  stackex  programming  latex  howto  nitty-gritty  yak-shaving  links  list  recommendations  books  guide  DSL 
may 2019 by nhaliday
python - Does pandas iterrows have performance issues? - Stack Overflow
Generally, iterrows should only be used in very very specific cases. This is the general order of precedence for performance of various operations:

1) vectorization
2) using a custom cython routine
3) apply
a) reductions that can be performed in cython
b) iteration in python space
4) itertuples
5) iterrows
6) updating an empty frame (e.g. using loc one-row-at-a-time)
q-n-a  stackex  programming  python  libraries  gotchas  data-science  sci-comp  performance  checklists  objektbuch  best-practices  DSL  frameworks 
may 2019 by nhaliday
bash - How to find/replace and increment a matched number with sed/awk? - Stack Overflow
/e allows you to pass matched part to external command, and do substitution with the execution result. Gnu sed only.
why you need to get first and last part of lines: https://unix.stackexchange.com/questions/180783/sed-e-and-g-flags-not-working-together
That is a bit tortuously written. What it means is that, after the completion of a s/// command for this line, if there was a change, the (new) line is executed as a command and its output used as the replacement for this line.

example of what I had to do to get this to work w/ embedded quotes:
gsed -E 's/^\("(.*)", ([0-9]+)(.*)/echo "(\\\\"\1\\\\", $((\2+54))\3"/e'
maps ("foo", 3... -> ("foo", 57..
q-n-a  stackex  programming  howto  terminal  unix  yak-shaving  multi  gotchas  DSL  gnu 
september 2017 by nhaliday
linux - How do I replace the last occurrence of a character in a string using sed? - Unix & Linux Stack Exchange
You can do it with single command:

sed 's/\(.*\)-/\1 /'
The point is that sed is very greedy, so matches as many characters before - as possible, including others -.
q-n-a  stackex  howto  workflow  yak-shaving  terminal  unix  programming  DSL 
august 2017 by nhaliday
unix - How to split a delimited string into an array in awk? - Stack Overflow
To split a string to an array in awk we use the function split():

awk '{split($0, a, ":")}'
# ^^ ^ ^^^
# | | |
# string | delimiter
# |
# array to store the pieces
If no separator is given, it uses the FS, which defaults to the space:

$ awk '{split($0, a); print a[2]}' <<< "a:b c:d e"
c:d
q-n-a  stackex  programming  howto  yak-shaving  terminal  unix  workflow  DSL 
august 2017 by nhaliday
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