JML

An experimental Parser and Java-Interpreter for a functional language inspired by SML

This is a toy project that I've created to learn more about functional programming languages and particularly Standard ML. Although this interpreter lacks some key features of SML like compile-time type checking and type inference, I've implemented much of the language's core features and added means to interact with Java-Objects.

I'm not actively working on this project and did never have any serious plans with it. If you're interested in functional programming on the JVM take a look at Scala that has been influenced by SML.

Build from source:

mvn clean install

Run the interactive read-eval-print-loop:

java -jar target/jml-*-jar-with-dependencies.jar

Now type in expressions and declarations separated by ";" and terminated by ";;"

Define the function "factorial"

fun factorial 0 = 1
	| factorial n = n * factorial (n-1)
;;

and then call it factorial 10 ;;

The function that append an element to a list might be implemented like this:

val rec append = fn
		(list,x) => 
		case list of
			nil => x::nil
			|
			h::t => h::(append(t,x))

append ([1,2,3],4)

will then return [1,2,3,4]. Note that nil is a synonym for the empty list [], [1] equals 1::nil and [1,2] equals 1::2::nil and so on.

The language's grammar is defined in FL.g.

See test.fl and global.fl to get a glimpse of the supported syntax and functionality.