blacktaxi

(ns monad-explore.core
  (:use clojure.algo.monads))

(defmacro let?
  "Almost the same as let. If you add the :ensure keyword paired with
  some predicate as a var in the let form, let? will not continue
  unless the predicate evaluates to true. (The predicate will have
  access to all bindings above.)"
  [bindings & body]
  (let [[bind [kwd pred & more]] (split-with (complement #{:ensure}) bindings)]

blacktaxi

(defmacro defconst [const-name const-val]
  `(def
     ~(with-meta const-name
       (assoc (meta const-name) :const true)) 
     ~const-val))

(defmacro defconsts [bindings]
  `(do
     ~@(map (fn [[const-name const-val]]
               `(defconst ~const-name ~const-val))

blacktaxi

One-line Tree in Python

Using Python's built-in defaultdict we can easily define a tree data structure:

def tree(): return defaultdict(tree)

That's it!

blacktaxi

##########################################################
# How to properly use Python. An efficient and yet educa-#
# tonal guide to the proper use of the lambda constru-   #
# ct in Python 2.x.     [DO USE THIS AT ALL TIMES]       #
#                                   by: e000 (13/6/11)   #
##########################################################

## Part 1. Basic LAMBDA Introduction ##
# Well, it's worth diving straight into what lambdas are.
# Lambdas are pretty much anonymous "one line" functions

blacktaxi

$snapins = Get-PSSnapin -Registered
$snapins | Add-PSSnapin
 
Get-Module -ListAvailable | Import-Module

Get-PSSnapin | Format-Table -autosize PSVersion, Name
Get-Module | Format-Table -autosize ModuleType, Name
 
function ff ([string] $glob) { get-childitem -recurse -include $glob }

blacktaxi

One of my favorite past times is to look at the notebooks of famous scientists. Da Vinci's notebook is well known, but there plenty others. Worshipping Da Vinci like no other, I bought a Think/Create/Record journal, used it mostly to keep jot down random thoughts and take notes. This was great in the beginning, but the conformity of lines drove me nuts. Only moleskines made blank notebooks, so I had to buy one.

At the same time I started a freelance project. The project itself is irrelevant, but suffice to say it was very complex and spanned several months. It seemed like a perfect opportunity to use the moleskine. Looking back, all my entries fell under few categories:

• Todo
• Question
• Thought
• Bug
• Feature

blacktaxi

def enum_class(cls):
    """Decorates a class to set it's attributes to values of their
    literal names. This is cool to use to make an 'enum' class and
    have PyCharm also infer it's members.

    Use it like so:
    >>> @enum_class
    ... class KindOfFruit:
    ...     Apple, Orange, Banana, Passionfruit = range(4)
    ...

blacktaxi

#!/usr/bin/env stack
-- stack --resolver lts-3.11 --install-ghc runghc --package array --package containers
{-# LANGUAGE ScopedTypeVariables #-}
module Main where

import qualified Data.ByteString.Char8 as B
import qualified Data.IntMap.Strict as IM
import qualified Data.Map.Strict as M
import qualified Data.Sequence as Seq
import Data.Sequence ((<|), (><))

blacktaxi

type SomethingViewModel() as this =
    inherit ViewModelBase()
    let (<<+) (_ : unit) (e : Microsoft.FSharp.Quotations.Expr) =
        this.OnPropertyChanged e

    let mutable somePropertyValue = ""
    member x.SomeProperty
        with get() = somePropertyValue
        and set value = (somePropertyValue <- value) <<+ <@ x.SomeProperty @>

blacktaxi

// This operator is used in the slides for this talk: http://fwaris.wordpress.com/2013/01/31/unraveling-the-mystery-of-monads/
// I haven't seen all the slides yet but I took a shot on implementing it myself.

let (<||>) a b = async {
	let! a = Async.StartChild a
	let! b = Async.StartChild b
	
	let! ar = a
	let! br = b