Martin Robson martinprobson

Vim Hints and Tips

A random collection of useful vim commands, hints and features.

1 Use `%:h/new_filename` to create a new file in the same directory as the current file being edited.

% - represents the current file
%:h is a modifier for the current file directory

Functional Programming Notes

Referential Transparency and Purity

An expression e is referentially transparent if, for all programs p, all occurrences of e in p can be replaced by the result of

Implicit Conversions in Scala

Summary

Very simple example showing how implicit conversions work in Scala.

Implicit Conversion Example

Let's try converting a StringBuffer into a List of characters.

Note We are using StringBuffer here instead of String because implicit conversion from String to List is already supported as standard in the Scala PreDef object. If we used String it would break rule 3 below.

	package net.martinprobson.scala.Extractors

	trait User

	class StandardUser(val firstName: String, val lastName:String) extends User

	object StandardUser {
	def unapply(s: StandardUser): Option[(String, String)] = Some((s.firstName,s.lastName))
	}

	import com.google.inject.{AbstractModule,Guice,Inject,ImplementedBy}


	/*
	This example shows how just in time (JIT) DI injection works in Google guice.
	*/
	object Main extends App {
	//
	// First, let us create an injector with a specific binding.
	//