Matt Russell mdr
mdr
/ gist:2753af206f4630421649c1c96f887d85
Created
November 27, 2025 21:52
Advent of Code 2024, Day 1, Part 1: lambda calculus
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| ((λa.λb.λc.(b (a c)) ((λd.λe.λf.(e (d f)) ((λg.λh.λi.(h (g i)) ((λj.λk.((j k) k) λl.λm.λn.(l (m n))) ((λo.λp.λq.(o (p q)) (((λr.(λs.(r λt.((s s) t)) λu.(r λv.((u u) v))) λw.λx.λy.λz.((z λA.λB.λC.(((w x) ((x y) A)) B)) y)) (λD.λE.λF.((D F) E) λG.λH.λI.((I G) H))) λJ.λK.K)) ((λL.(λM.(L λN.((M M) N)) λO.(L λP.((O O) P))) λQ.λR.λS.((S λT.λU.λV.(((R T) ((Q R) U)) S)) λW.λX.X)) ((λY.λZ.λaa.((Y aa) Z) ((λab.λac.(ac ab) λad.λae.(((((λaf.λag.λah.λai.(((ai af) ag) ah) λaj.((((λak.λal.λam.λan.(((an ak) al) am) λao.λap.ao) λaq.λar.λas.as) λat.at) ((λau.(λav.(av av) λaw.(au (aw aw))) λax.(((λay.λaz.λaA.λaB.(((aB ay) az) aA) λaC.λaD.λaE.aC) λaF.(λaG.λaH.λaI.λaJ.(aI (((aG aH) aI) aJ)) (ax aF))) λaK.(λaL.λaM.λaN.λaO.(aO (((aL aM) aN) aO)) (ax aK)))) aj))) λaP.(((λaQ.λaR.λaS.λaT.(((aT aQ) aR) aS) λaU.λaV.aV) λaW.(aP aW)) λaX.λaY.λaZ.aZ)) λba.λbb.(((bb (ba bb)) λbc.λbd.λbe.be) λbf.(ba bf))) ad) ((((λbg.λbh.λbi.λbj.(((bj bg) bh) bi) λbk.λbl.λbm.bk) λbn.λbo.λbp.λbq.(bp bn)) λbr.λbs.λbt.λbu.(bu br)) ae))) (λbv.λbw.λbx.(bv (bw bx) |
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| @file:Suppress("NonAsciiCharacters") | |
| sealed class Either<out A, out B> | |
| data class Left<out A> constructor(val value: A) : Either<A, Nothing>() | |
| data class Right<out B> constructor(val value: B) : Either<Nothing, B>() | |
| typealias `∧`<φ, ψ> = Pair<φ, ψ> | |
| typealias `∨`<φ, ψ> = Either<φ, ψ> |
mdr
/ givenWhenThen.js
Created
April 1, 2021 17:23
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| const loadSpec = async () => ({ | |
| given: () => "I have 100 shares of MSFT stock", | |
| when: () => "When I ask to sell 20 shares of MSFT stock", | |
| then: () => "Then I should have 80 shares of MSFT stock" | |
| }) | |
| const printSpec = async () => { | |
| const { given, when, then } = await loadSpec() | |
| console.log(given()) | |
| console.log(when()) |
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| // Implementation of DAGs based on: | |
| // Jeremy Gibbons, An Initial-Algebra Approach to Directed Acyclic Graphs, 1995 | |
| // https://www.researchgate.net/publication/2423982_An_Initial-Algebra_Approach_to_Directed_Acyclic_Graphs | |
| // | |
| // Good: | |
| // ✅ Immutable, compositional representation that supports structural sharing | |
| // ✅ Correct by construction: no way to create cyclic graphs, so no need to check | |
| // ✅ Some graph operations are easy: topological sort, certain replacement graph transformations | |
| // ✅ Cool underlying theory: graphs are arrows in a symmetric monoidal category | |
| // ⚠️ Extensions to the default idea of a DAG: supports multiple edges between the same vertices, ordered ports, and |
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| ══╡ EXCEPTION CAUGHT BY FLUTTER TEST FRAMEWORK ╞════════════════════════════════════════════════════ | |
| The following assertion was thrown running a test: | |
| 'dart:ui/hash_codes.dart': Failed assertion: line 15: '<optimized out>': is not true. | |
| Either the assertion indicates an error in the framework itself, or we should provide substantially | |
| more information in this error message to help you determine and fix the underlying cause. | |
| In either case, please report this assertion by filing a bug on GitHub: | |
| https://github.com/flutter/flutter/issues/new?template=BUG.md | |
| When the exception was thrown, this was the stack: |
mdr
/ AsyncSerializer.js
Last active
September 12, 2018 16:34
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| class AsyncSerializer { | |
| constructor() { | |
| this._previousPromise = Promise.resolve(null) | |
| } | |
| serialize = f => { | |
| const newPromise = this._previousPromise.then(() => f()) | |
| this._previousPromise = newPromise | |
| return newPromise | |
| } |
mdr
/ MyContainerComponent.jsx
Last active
July 20, 2018 08:52
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| import React from 'react' | |
| import { shallow } from 'enzyme' | |
| const flushPromises = () => new Promise(resolve => setImmediate(resolve)) | |
| const fetchTheData = jest.fn() | |
| class MyContainerComponent extends React.Component { | |
| state = { error: null } |
mdr
/ AuthenticationService.kt
Created
July 19, 2018 11:13
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| package gems.user.service | |
| import com.google.inject.ImplementedBy | |
| import com.google.inject.Inject | |
| import gems.user.dao.UserDao | |
| import gems.user.dao.entity.User | |
| import gems.user.service.dto.Credentials | |
| import gems.user.service.session.Session | |
| import gems.user.service.session.SessionManager |
mdr
/ gist:5bf6a5fd7ec70a043c9dae2773f04d47
Last active
July 9, 2018 16:08
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| backend | 15:51:16.951 [main] DEBUG Application - Class Loader: sun.misc.Launcher$AppClassLoader@75b84c92: [/home/gradle/app/backend/build/classes/java/main, /home/gradle/app/backend/build/classes/kotlin/main/, /home/gradle/app/backend/build/resources/main/, /home/gradle/.gradle/caches/modules-2/files-2.1/io.ktor/ktor-server-netty/0.9.2/3ec623b4e61942af1968f44adf00ed14411705f3/ktor-server-netty-0.9.2.jar, /home/gradle/.gradle/caches/modules-2/files-2.1/io.ktor/ktor-auth-jwt/0.9.2/e156bae7c5e75a2492822c7ebfb4611a51c09b55/ktor-auth-jwt-0.9.2.jar, /home/gradle/.gradle/caches/modules-2/files-2.1/io.ktor/ktor-auth/0.9.2/cc9bcc5bd3fd1604071c6f25aa42fc3dfa9c615c/ktor-auth-0.9.2.jar, /home/gradle/.gradle/caches/modules-2/files-2.1/io.ktor/ktor-jackson/0.9.2/424f4a16296755e21219d65190e03eac53b0843b/ktor-jackson-0.9.2.jar, /home/gradle/.gradle/caches/modules-2/files-2.1/org.mpierce.ktor.csrf/ktor-csrf/0.3.0/defdb620ad156ac64c265f0dcf3bdd1fb78f2bb9/ktor-csrf-0.3.0.jar, /home/gradle/.gradle/caches/modules-2/files-2.1 |
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| strictfp \u0070\u0075\u0062\u006c\u0069\u0063\u0020\u0063\u006c\u0061\u0073\u0073\u0020\u0052\u0065\u0066\u0075\u0063\u0074\u0020\u007b | |
| \uuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu0020 | |
| interface λ<A, B> { | |
| public B call(A x); | |
| } | |
| interface RecursiveFunc<F> extends λ<RecursiveFunc<F>, F> { | |
| } | |
| private static boolean isDivisibleBy(int n, final int m) { |
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