F# Tricks: Concise BoolToInt

As a C# programmer, you'd probably write BoolToInt as follows in F#:

	let boolToInt3 b = 
	   if b = true then 
		1
	   elif b = false
		0

Not a big win over C# yet, but a few things to point out about the concise syntax: Indentation implies blocks. There is no 'return' keyword. This function is statically typed, you don't see types since the compiler infers the types.

As a novice F# programmer a trick you learn is pattern matching. Pattern matching is like a case statement, but it's an expression and it's really powerful. I'll go into more details on pattern matching in future posts. For now, notice the elegance of the below:

	let boolToInt2 b = 
	    match b with 
		| true -> 1 
		| false -> 0 

Pattern matching is so useful to F# there is a syntax for creating a function of one parameter that only pattern matches, using that syntax, we define boolToInt in the final form of:

	let boolToInt3 = function 
	    | true -> 1 
	    | false -> 0 

Posted in: f#