| // The two sweetspots are 8-bit and 4-bit tags. In the latter case you can fit 14 32-bit keys in | |
| // a cacheline-sized bucket and still have one leftover byte for metadata. | |
| // As for how to choose tags for particular problems, Google's Swiss table and Facebook's F14 table | |
| // both use hash bits that weren't used for the bucket indexing. This is ideal from an entropy perspective | |
| // but it can be better to use some particular feature of the key that you'd otherwise check against anyway. | |
| // For example, for 32-bit keys (with a usable sentinel value) you could use the 8 low bits as the tag | |
| // while storing the remaining 24 bits in the rest of the bucket; that fits 16 keys per bucket. Or if the keys | |
| // are strings you could store the length as the discriminator: with an 8-bit tag, 0 means an empty slot, | |
| // 1..254 means a string of that length, and 255 means a string of length 255 or longer. With a 4-bit tag |
| {-# LANGUAGE GADTs, RankNTypes, TypeFamilies, DataKinds, PolyKinds, TypeOperators, ScopedTypeVariables #-} | |
| -- Lots of ways you can phrase this, but this works for me | |
| -- For folks who haven't seen it before, this is "the essence of the sum type" and sigma stands for sum. | |
| -- You see it far more often in dependent types than elsewhere because it becomes a lot more pleasant to | |
| -- work with there, but it's doable in other contexts too. Think of the first parameter to the data | |
| -- constructor as a generalized "tag" as we talk about in "tagged union", and the second parameter is the | |
| -- "payload". It turns out that you can represent any simple sum type you could write in Haskell this way | |
| -- by using a finite and enumerable `f`, but things can get more unusual when `f` isn't either. In such | |
| -- cases, it's often easier to think of this as the essence of existential types. |
| let | |
| platform = crossPkgs.platforms.armv7l-hf-multiplatform; | |
| crossSystem = { | |
| config = "arm-linux-gnueabihf"; | |
| platform = platform; | |
| libc = "glibc"; | |
| arch = "arm"; | |
| float = "hard"; | |
| fpu = "vfp"; |
| ;;; sow.el --- Variable commands for scrolling the other window. | |
| ;; Copyright (C) 2016 Andreas Politz | |
| ;; Author: Andreas Politz <[email protected]> | |
| ;; Keywords: extensions, frames | |
| ;; This program is free software; you can redistribute it and/or modify | |
| ;; it under the terms of the GNU General Public License as published by | |
| ;; the Free Software Foundation, either version 3 of the License, or |
| {-# LANGUAGE DeriveFunctor #-} | |
| {-# LANGUAGE MultiParamTypeClasses #-} | |
| {- | |
| Explores Free Monads (DSLs) and Cofree Comonads (interpreters) and | |
| their relationship. | |
| Most of the code in this file comes from (1) below. Only minor | |
| modifications are made - semantics are preserved. |
| #!/bin/bash -e | |
| name=$(sed -n -e 's/^[nN]ame:\s\+\(.\+\)/\1/p' *.cabal) | |
| old_ver=$(sed -n -e 's/^[vV]ersion:\s\+\(.\+\)/\1/p' *.cabal) | |
| has_docs=1 | |
| grep -i '^Library' *.cabal || has_docs=0 | |
| echo "Package name: $name" | |
| echo "Current version: $old_ver" | |
| echo "Has documentation: $has_docs" |
| -- | simple/basic Scala -> Haskell translation of Runar's presentation | |
| -- | (https://dl.dropboxusercontent.com/u/4588997/ReasonablyPriced.pdf) | |
| -- | trying to use minimal extensions and magic. | |
| -- | (earlier I had a version using MultiParamTypeClasses for Runar's | |
| -- | Inject class, but scraped it opting for simplicity) | |
| -- | my question: what do we lose by moving towards simplicity? | |
| -- | Future work: use DataKinds, TypeOperators, and potentially TypeFamilies | |
| -- | to maintain and automate the folding of types in Coproduct. | |
| {-# LANGUAGE Rank2Types, DeriveFunctor #-} |
| -- in reply to http://www.reddit.com/r/haskell/comments/21mja6/make_lllegal_state_transitions_unrepresentable/ | |
| -- | |
| -- We implement a tiny language with three commands: Open, Close, and Get. | |
| -- The first Get after an Open returns 1, the second Get returns 2, and so on. | |
| -- | |
| -- Get is only valid while the state is open, and | |
| -- Open must always be matched by a Close. | |
| -- We enforce both restrictions via the type system. | |
| -- | |
| -- There are two valid states: Opened and Closed. |
This simple script will take a picture of a whiteboard and use parts of the ImageMagick library with sane defaults to clean it up tremendously.
The script is here:
#!/bin/bash
convert "$1" -morphology Convolve DoG:15,100,0 -negate -normalize -blur 0x1 -channel RBG -level 60%,91%,0.1 "$2"
| #! /bin/bash | |
| thedate=$(date "+%Y-%m-%d-%Hh-%Mm-%Ss") | |
| thecommit=$(git log --format=%H HEAD^1..HEAD) | |
| if git status | grep "Changes"; then | |
| echo "the are uncommited changes in the repo. We can't benchmark that."; | |
| exit 1; |