Ciro Santilli @cirosantilli 37

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sudo Updated 2025-07-16

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Availability: unix.stackexchange.com/questions/48522/how-universal-is-sudo

xkcd.com/149/

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The Linux kernel responds to ICMP directly Updated 2025-07-16

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There is no userland process for it, it is handled directly by the Linux kernel: unix.stackexchange.com/questions/439801/what-linux-process-is-responsible-for-responding-to-pings/768739#768739

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Type-I superconductor Updated 2025-07-16

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Figure 1.
Sketch of the typical superconducting phase diagram of a Type-I superconductor
. Source.

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TypeScript Updated 2025-07-16

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TypeScript is good. It does find errors in your JavaScript. But it is a form of "turd polishing". But Ciro Santilli would rather have a polished turd than a non-polished one.

Part of the reason TypeScript became popular is due to the universality of asset bundlers. Once you are already using an asset bundler, changing the .js extension into .ts to get a less shitty experience is an easy choice.

The other big reason is that JavaScript is so lose with type conversions, notably undefined happily converting to strings without problems, and any missing properties of Object happily being undefined. We should actually use ES6 Map everywhere instead of using Objects as maps.

Since TypeScript is not the default form of the language however, it inevitably happens that you need to add external types for a gazillion projects that are using raw JavaScript, and sometimes fight a lot to get things to work. And so we have: github.com/DefinitelyTyped/DefinitelyTyped. Not sure if this is beautiful, or frightening.

But in the end, as with other type of static linters, TypeScript generally transforms a few hard to debug runtime issues, into a bunch of stupid to solve compile time issues, which is generally a good thing.

The fact that this it parses comments JSDoc comments in JavaScript files is quite amazing.

Examples under typescript. Run each one of them with:

npx tsc example.ts
node example.js

Helper:

tsr() (
  # ts Run
  f="$1"
  npx tsc "$f"
  node "${f%.*}.js"
)
tsr example.ts

typescript/inferFromInit.ts. Should fail with:
hello.ts:2:1 - error TS2322: Type 'string' is not assignable to type 'number
since TypeScript infers the type of i from first assignment as string, and we then attempt a number assignment later on
typescript/inferAfterInit.ts. Does not fail, as the first assignment cannot be computationally determined at runtime without breaking computer science.
typescript/js-from-ts/main.ts: call JavaScript file typescript/js-from-ts/notmain.js from TypeScript.
```
npx tsc jsFromTs.ts && node jsFromTs.js
```
TODO we are unable to make it typecheck that require, i.e. make that fail, but we've seen cases in complex codebases where that did happen and www.typescriptlang.org/docs/handbook/intro-to-js-ts.html has infinite information on supporting it. So... how to make it fail??
typescript/functionArgument.ts: basic argument tests
- typescript/functionOptionalArgument.ts: f(n?: number)
typescript/functionOptions.ts: f({n, s}: {n: number, s: string})

Some major annoyances of TypeScript:

destructuring assignment in function arguments requires repeating all arguments:
stackoverflow.com/questions/12710905/how-do-i-dynamically-assign-properties-to-an-object-in-typescript how to dynamically assign properties to objects without defining explicit interfaces? We really need a syntax of type:
```
const myobj = {
  i: 2,
  [s string],
}
if (something) {
  myobj.s = 'asdf'
}
```

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1D Ising model Updated 2025-07-16

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Bibliography:

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3D Ising model Updated 2025-07-16

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DC Josephson effect Updated 2025-07-16

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IBM Spectrum LSF Updated 2025-07-16

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JAR (file format) Updated 2025-07-16

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Monaco (editor) Updated 2025-07-16

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Either extracted from, or designed for, vscode by Microsoft:

However also at the same time very limited integration with vscode, that makes using it for VScode compatibility almost useless, e.g.:

you can't reuse the syntax defintions!
- stackoverflow.com/questions/37936919/writing-visual-studio-code-syntaxes-in-monarch
- github.com/Microsoft/vscode/issues/216

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The product of a exponential of the compact algebra with that of the non-compact algebra recovers a simple Lie from its algebra Updated 2025-07-16

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Example at: Lie Groups, Physics, and Geometry by Robert Gilmore (2008) Chapter 7 "EXPonentiation".

Furthermore, the non-compact part is always isomorphic to

R^{n}

, only the non-compact part can have more interesting structure.

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United States Department of Defense Updated 2025-07-16

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Upsert Updated 2025-07-16

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UPSERT is extremely handy, and reduces the number of find, check on server, update loops. But RETURNING is a fundamental part of that (to get the updated/existing) ID. Can't believe SQL hasn't standardized it yet as of 2022. But both SQLite and Postgres support it with similar syntax thankfully.

nodejs/sequelize/raw/upsert.js

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URL Updated 2025-07-16

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Varun-Hegde/Conduit_NodeJS Updated 2025-07-16

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Very raw. Easy to understand. Relatively well organiezd. But also very buggy at 3ab8d9f849a1cdf2985a8d123b1893f0fd4e79ab: github.com/Varun-Hegde/Conduit_NodeJS/issues/3, I just can't trust it. There must be several helper libraries that would greatly DRY up the repetitive CRUD. Ciro hates the style :-) 4 space indents, no space after commas, no semicolon. Not based on github.com/gothinkster/node-express-realworld-example-app which is essentially one of the reference implementations, so from scratch apparently, which is a bad sign.

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Water Margin adaptation Updated 2025-07-16

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