mmynsted

#Outstanding FP, CS, and other books we like.

Structure and Interpretationof Computer Programsor SICP

...perfection is finally attained not when there is no longer anything to add, but when there is no longer anything to take away...

-- Antoine de Saint-Exupéry

Glossary of Functional Programming Terms

Functor

A type constructor F[_] together with an operation forall A, B. (A => B) => F[A] => F[B] that satisfies FunctorLaw, i.e. that a series of maps may be freely rewritten as a single map on a composed function, and that the identity function, lifted, is a no-op.

A good example from scalaz

def map[A, B](fa: F[A])(f: (A) ⇒ B): F[B]

	# pushd /opt/local/var/macports/registry
	# mv registry.db registry.db.old
	# sqlite3 registry.db.old

	sqlite> .load /opt/local/var/macports/sources/rsync.macports.org/release/base/src/cregistry/macports.sqlext
	sqlite> .mode insert
	sqlite> .output dump_all.sql
	sqlite> .dump
	sqlite> .exit

	#!/bin/bash

	rm -vrf /System/Library/Extensions/zfs.kext
	rm -vrf /System/Library/Filesystems/zfs.fs
	rm -vf /usr/lib/libzfs.dylib
	rm -vrf /usr/lib/libzfs.dylib.dSYM
	rm -vf /usr/lib/libzpool.dylib
	rm -vrf /usr/lib/libzpool.dylib.dSYM
	rm -vf /usr/local/bin/zoink
	rm -vrf /usr/local/bin/zoink.dSYM

	!/bin/sh
	count=0
	interval=60
	while true
	do
	echo -ne "$(date +%Y-%m-%dT%H:%M:%S) \| $((count/interval)) mins : $1"'\r'
	let count+=interval
	sleep $interval
	done

	val scalacFlags = Seq(
	"-deprecation",
	"-encoding", "UTF-8",
	"-feature",
	"-language:existentials",
	"-language:experimental.macros",
	"-language:higherKinds",
	"-language:implicitConversions",
	"-unchecked",
	"-Xfatal-warnings",

	object Main extends App {

	def toOpt(s: Set[String]): Option[String] = s match {
	case x if !x.isEmpty => Some(x.mkString(" "))
	case _ => None
	}
	val a: Set[String] = Set()
	val b: Set[String] = Set("a", "b")
	println(s"a = ${toOpt(a)}")
	println(s"b = ${toOpt(b)}")