Syntax

Types

• num
• bool
• string
• unit

Variables

val age : num = 10;
val name : string = "foobar";
val ishappy? : bool = false;
val dontcare : unit = console.log("hello world");

Operators

// globals
==, !=, >=, <=, >, <

// num
+ , - , / , * , %, 

// string
^ (concat)

// bool
&&, ||, !, 

Lists

val friends : list string = ["foo", "bar", "baz"];
val nums : list num = [1, 2, 3, 4];
val lists_of_friends : list list string = [["foo"], ["bar"], ["baz"]];
val head : string = List.hd(friends);
val rest : list string = List.tl(friends);

Map

val passwords : <string: num> = {
 "foo" : 1245,
 "bar" : 5567,
 "baz" : 5533
};

val students : <string: <string: num>> = {
  "foo": { "marks": 97 },
  "bar": { "marks": 23 },
  "baz": { "marks": 47 }
};

val foo = Map.get(passwords, "foo");
val foo = Map.set(passwords, "foo", 12345);

Control-flow

val iseven? = if (x % 2 == 0) then {true;} else {false;}

Function

// simple expression
def square (x: num) : num { 
   x * x;
}

// function multi-line
def cube (x: num): num {
  val sq = square(x);
  x * sq;
}

// equivalent to def sq (x: num) : num = x * x;
val sq : (num) -> num = (x: num) : num => x * x;

// defining map
def map (f: (T) -> U, l: list T): list U {
   if (List.empty?(l)) 
   then { []; }
   else {
     val res = f(List.hd(l));
     List.cons(res, map(f, List.tl(l)));
   }
} 

// applying map
val squares : list num = map((x: num) : num => x * x, [1, 2, 3, 4]);

// finding factorial
def fact (n: num) : num {
  if (n == 0) then { 
     1;
  } else {
     n * fact(n-1);
  } 
}

// summing a list 
def sumlist (xs: list num) : num {
  val aux = (total: num, l: list num) => {
     if (List.empty?(l)) 
     then { total; }
     else { aux (total + List.hd(l), List.tl(l)); } 
  };
  aux(0, xs);
}

// printing a list
def printlist (xs: list string) : unit {
  List.iter((x: string) : unit => { println(x); } , xs);
}