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@t0yv0
t0yv0 / subtyping.v
Last active February 28, 2021 01:47
Demonstrating TypeScript 0.8 type system to be unsound. The subtyping relationship is defined in a way that admits the following code that results in TypeError exception being thrown.
Require Import Utf8.
Inductive subtype (a b : Set) : Set :=
| ST : (a -> b) -> subtype a b.
Infix ":>" := subtype (at level 50).
Definition st {x y} f := ST x y f.
Definition unpack {a b : Set} (st : a :> b) :=
/*
* http://dysphoria.net/code/hindley-milner/HindleyMilner.scala
* Andrew Forrest
*
* Implementation of basic polymorphic type-checking for a simple language.
* Based heavily on Nikita Borisov’s Perl implementation at
* http://web.archive.org/web/20050420002559/www.cs.berkeley.edu/~nikitab/courses/cs263/hm.html
* which in turn is based on the paper by Luca Cardelli at
* http://lucacardelli.name/Papers/BasicTypechecking.pdf
*
@twanvl
twanvl / Sorting.agda
Last active December 2, 2022 16:44
Correctness and runtime of mergesort, insertion sort and selection sort.
module Sorting where
-- See https://www.twanvl.nl/blog/agda/sorting
open import Level using () renaming (zero to ℓ₀;_⊔_ to lmax)
open import Data.List hiding (merge)
open import Data.List.Properties
open import Data.Nat hiding (_≟_;_≤?_)
open import Data.Nat.Properties hiding (_≟_;_≤?_;≤-refl;≤-trans)
open import Data.Nat.Logarithm
open import Data.Nat.Induction
Address Ordinal Name Library
------- ------- ---- -------
4A781000 AllocateAndInitializeSid ADVAPI32
4A781004 InitializeAcl ADVAPI32
4A781008 RegCloseKey ADVAPI32
4A78100C RegOpenKeyExW ADVAPI32
4A781010 GetTokenInformation ADVAPI32
4A781014 GetLengthSid ADVAPI32
4A781018 LsaLookupNames ADVAPI32
4A78101C AddAccessAllowedAce ADVAPI32
@david-christiansen
david-christiansen / PlusRewrite.idr
Last active August 8, 2016 20:31
Simplifying "plus" expressions with rewrite-rule combinators and quasiquotes in Idris
module PlusRewrite
import Language.Reflection
import Language.Reflection.Utils
rewrite_plusSuccRightSucc : TT -> Maybe Tactic
rewrite_plusSuccRightSucc `(plus ~n (S ~m)) = Just $ Rewrite `(plusSuccRightSucc ~n ~m)
rewrite_plusSuccRightSucc `(S ~n) = rewrite_plusSuccRightSucc n
rewrite_plusSuccRightSucc `(plus ~n ~m) = rewrite_plusSuccRightSucc n <|> rewrite_plusSuccRightSucc m
rewrite_plusSuccRightSucc _ = Nothing
@agrif
agrif / PeirceLEM.hs
Last active March 14, 2017 20:14 — forked from ion1/PeirceLEM.hs
-- Exercise: prove Peirce’s law <=> law of excluded middle in Haskell
{-# LANGUAGE Rank2Types #-}
import Data.Void
import Data.Bifunctor
import Data.Functor.Identity
type Not a = a -> Void
@fay59
fay59 / Quirks of C.md
Last active January 23, 2024 04:24
Quirks of C

Here's a list of mildly interesting things about the C language that I learned mostly by consuming Clang's ASTs. Although surprises are getting sparser, I might continue to update this document over time.

There are many more mildly interesting features of C++, but the language is literally known for being weird, whereas C is usually considered smaller and simpler, so this is (almost) only about C.

1. Combined type and variable/field declaration, inside a struct scope [https://godbolt.org/g/Rh94Go]

struct foo {
   struct bar {
 int x;
@rxwei
rxwei / ad-manifesto.md
Last active November 9, 2023 09:58
First-Class Automatic Differentiation in Swift: A Manifesto
@racerxdl
racerxdl / LFE5U-25F.cfg
Created June 4, 2020 22:17
FPGA Board FT232
jtag newtap ecp5 tap -irlen 8 -expected-id 0x41111043
@Gadgetoid
Gadgetoid / Makefile
Last active August 25, 2023 01:50
Pi 400 KB
CFLAGS_ALL=-I../libusbgx/build/include -I../bcm2835-1.68/build/include -L../bcm2835-1.68/build/lib -I../lua-5.4.0/src -L../libusbgx/build/lib -L../libserialport/build/lib -L../lua-5.4.0/src -lpng -lz -lpthread -llua -lm -lbcm2835 -ldl
pi400: CFLAGS+=-static $(CFLAGS_ALL) -lusbgx -lconfig -DPI400_USB
pi400: pi400.c gadget-hid.c
$(CC) $^ $(CFLAGS) -o $@
pi400test: CFLAGS+=-static $(CFLAGS_ALL) -lusbgx -lconfig
pi400test: pi400.c gadget-hid.c
$(CC) $^ $(CFLAGS) -o $@