jcoglan

class Mailer < ApplicationMailer
  def self.my_class_method
    build_the_mail.deliver_now        # this invokes (B)
  end
  
  def build_the_mail                  # (A) this is the instance method you write
    mail(
      # ...
    )
  end

jcoglan

// a.c

size_t Chunk_copy(Chunk *src, size_t src_start, Chunk *dst, size_t dst_start, size_t n)
{
    if (!Chunk_bounds_check(src, src_start, n)) return 0;
    if (!Chunk_bounds_check(dst, dst_start, n)) return 0;

    memcpy(dst->data + dst_start, src->data + src_start, n);

jcoglan

require "./diff"

class MyersLinear
  Window = Struct.new(:left, :top, :right, :bottom) do
    def width
      right - left
    end

    def height
      bottom - top

jcoglan

module Lambda where

import Control.Monad (when)
import Data.List (nub, sort)


data LTerm = Var String
           | Lambda String LTerm
           | Apply LTerm LTerm
           deriving (Eq)

jcoglan

require_relative './pattern'

Pattern.define  :TmIf,
                :TmTrue,
                :TmFalse,
                :TmZero,
                :TmSucc,
                :TmPred,
                :TmIsZero

jcoglan

require_relative "../myers/linear"

class Diff3
  def self.merge(o, a, b, differ: MyersLinear)
    o = o.lines if o.is_a?(String)
    a = a.lines if a.is_a?(String)
    b = b.lines if b.is_a?(String)

    new(o, a, b, differ).tap(&:run)
  end

jcoglan

The Myers diff algorithm

The following based on Myers' original paper.

The edit graph

To use the example from the paper, say you want to calculate the difference between two strings:

jcoglan

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

typedef char * BLOB;

typedef struct BufferChunk {
    int length;
    int cursor;
    BLOB data;

jcoglan

#include <stdio.h>
#include <assert.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>

struct Address {
    int id;
    int set;
    char *name;

jcoglan

var crypto = require('crypto');


var key  = crypto.randomBytes(32),
    iv   = crypto.randomBytes(12),
    mode = 'aes-256-gcm';

var message = new Buffer('Hello, world!', 'utf8');