README.md

YegorIfThenElseSketch

This is a couple of sketches (overloading, visitor) I put together to illustrate a potential way to eliminate an IfThenElse block with polymorphism and decorators

http://www.yegor256.com/2016/08/10/if-then-else-code-smell.html

According to Yegor this is bad:

class DyTalk implements Talk {
	void modify(Collection<Directive> dirs) {
		if (!dirs.isEmpty()) {
			// Apply the modification
			// and save the new XML document
			// to the DynamoDB table.
		}
	}
}

I implemented illustrations using simple method overloading as well as a visitor pattern approach. The examples are in Swift so here's a couple of reminders for Java programmers:

• Protocols are essentially analogous to Interfaces
• Contructors are init()
• Parameters are given as "variableName: Type"
• Array types are [ObjectType]

I think everything else is pretty self explanatory

Example usage of Vistor code that does not have an if statement:

class ExampleUsage {
	var dirs: Collection
	init() {
		dirs = EmptyCollection()
	}

	func add(dir: Dir) {
		self.dirs = dirs.add(dir)
	}

	func talk() {
		dirs.letsHaveATalk(DyTalk())
	}
}