hallettj

Quickstart

Get a development environment and project scaffold set up in a jiffy.

Development environment

First install node and npm. There are instructions here:

hallettj

/* @flow */

type Tree<T> =
  | { type: "Node", value: T, left: Tree<T>, right: Tree<T> }
  | { type: "EmptyTree" }

function find<T>(p: (v: T) => boolean, t: Tree<T>): T | void {
  var l, v

  if (t.type === "Node") {

hallettj

# Category Theory proofs in Idris

Idris is a language with dependent types, and is similar to Agda.
What distinguishes Idris is that it is intended to be a general-purpose language first,
and a theorem prover second.
To that end it supports optional totality checking
and features to support writing DSLs:
type classes,
do notation,
monad comprehensions (i.e., a more general form of list comprehension),

hallettj

module Logic

infixr 1 ==>

(==>) : Bool -> Bool -> Bool
False ==> _ = True
True  ==> x = x

data Exists : (A : Type) -> (P : A -> Bool) -> Type where
  exists : {A : Type} -> {P : A -> Bool} -> (a : A) -> so (P a) -> Exists A P

hallettj

Keybase proof

I hereby claim:

• I am hallettj on github.
• I am hallettj (https://keybase.io/hallettj) on keybase.
• I have a public key whose fingerprint is A378 B079 9F05 93C0 B499 DD02 8FB4 E35F E86B 913B

To claim this, I am signing this object:

hallettj

/*
 * The implementation
 */

function du(comprehension) {
    return function(/* args */) {
        var gen = comprehension.apply(null, arguments)
        return next();

        function next(v) {

hallettj

# open vim in a new split
bind e split-window -h -c "#{pane_current_path}" sensible-editor

# shortcuts for common git operations
bind g split-window -h -c "#{pane_current_path}" 'GIT_PAGER="less -+F" git lg'
bind D split-window -h -c "#{pane_current_path}" 'GIT_PAGER="less -+F" git diff'
bind C split-window -h -c "#{pane_current_path}" 'GIT_PAGER="less -+F" git diff --cached'
bind A split-window -h -c "#{pane_current_path}" 'git add -p'

hallettj

!
! Invert number row
!
! This changes the behavior of keys in the number row, but does not
! affect the number pad.
!
keycode  10 = exclam 1 1 exclam
keycode  11 = at 2 2 at
keycode  12 = numbersign 3 3 numbersign
keycode  13 = dollar 4 4 dollar

hallettj

import Control.Applicative ((<$>), (<*>))
import Control.Concurrent.Async (Concurrently(..), runConcurrently)
import Data.Monoid (Monoid, (<>), mappend, mempty)

instance (Monoid a) => Monoid (IO a) where
    mappend x y = runConcurrently $ (<>) <$> Concurrently x <*> Concurrently y
    mempty = return mempty

-- example:
action = getLine <> getLine

hallettj

var fs = require('fs');
var exec = require('child_process').exec;

var templ_ = fs.readFileSync('package.json.template', { encoding: 'UTF-8' });
var templ  = JSON.parse(templ_);

var deps = {};
exec("npm search substack | grep '=substack' | awk '{ print $1 }'", function(err, stdout) {
    var lines = stdout.toString('UTF-8');
    lines.split("\n").forEach(function(line) {