[gdome@tempest ~] sml
Standard ML of New Jersey v110.78 [built: Wed Jan 14 12:52:09 2015]

- 1 + 2;
val it = 3 : int

- 1 + 2
= +3;  
val it = 6 : int

- 3 + 4
= ;
val it = 7 : int

- 3+4;
val it = 7 : int
-        7
=    +
=            8
= ;
val it = 15 : int

- 3+4*5;
val it = 23 : int

- val a = 2+3;
val a = 5 : int

- a*a;
val it = 25 : int

- a = 5;
val it = true : bool

- it;
val it = true : bool

- a+10;
val it = 15 : int

- it*10;
val it = 150 : int

- 2-5;
val it = ~3 : int

- ~3
= ;
val it = ~3 : int

- -3;
stdIn:21.1 Error: expression or pattern begins with infix identifier "-"
stdIn:21.1-21.3 Error: operator and operand don't agree [overload conflict]
  operator domain: [- ty] * [- ty]
  operand:         [int ty]
  in expression:
    - 3

- ~(2+3);
val it = ~5 : int

- 7/2;
stdIn:22.1-22.4 Error: operator and operand don't agree [overload conflict]
  operator domain: real * real
  operand:         [int ty] * [int ty]
  in expression:
    7 / 2

- 7.0/2.0;
val it = 3.5 : real

- 7.0/2;
stdIn:23.1-23.6 Error: operator and operand don't agree [overload conflict]
  operator domain: real * real
  operand:         real * [int ty]
  in expression:
    7.0 / 2

- 7 div 2;
val it = 3 : int

- 7 mod 3;
val it = 1 : int

- 7 rem 3;
stdIn:25.3-25.6 Error: unbound variable or constructor: rem
stdIn:25.1-25.8 Error: operator is not a function [overload conflict]
  operator: [int ty]
  in expression:
    7 <errorvar>

(* This is a comment. (* And comments nest properly. *) Yay! *)

(* How to know what operators/functions are available in the "top-level" interpreter?
   Look at http://sml-family.org/Basis/top-level-chapter.html *)

- val inc = fn x => x+1;
val inc = fn : int -> int

- val incReal = fn x => x+1.0;
val incReal = fn : real -> real

- inc 10;
val it = 11 : int

- inc 5.0
= ;
stdIn:28.1-28.8 Error: operator and operand don't agree [tycon mismatch]
  operator domain: int
  operand:         real
  in expression:
    inc 5.0

- val dbl = fn y => y*2;
val dbl = fn : int -> int

- dbl 10;
val it = 20 : int

- fun sub5 z = z - 5;
val sub5 = fn : int -> int

- sub5 17;
val it = 12 : int

- sub5;
val it = fn : int -> int

- (fn a => a*3) 10;
val it = 30 : int

- val weird = fn x => (x+2)*(x+3.0);
stdIn:35.28-35.33 Error: operator and operand don't agree [overload conflict]
  operator domain: [+ ty] * [+ ty]
  operand:         [+ ty] * real
  in expression:
    x + 3.0

- Real.fromInt(2);
[autoloading]
[library $SMLNJ-BASIS/basis.cm is stable]
[autoloading done]
val it = 2.0 : real

- val weird = fn x => (Real.fromInt(x+2))*(Real.fromInt(x)+3.0);
val weird = fn : int -> real

- dbl 5;

val it = 10 : int

- dbl(5);
val it = 10 : int

- dbl((5));
val it = 10 : int

- (dbl 5)
= ;
val it = 10 : int

- inc (dbl 5);
val it = 11 : int

- (inc dbl) 5;
stdIn:43.2-43.9 Error: operator and operand don't agree [tycon mismatch]
  operator domain: int
  operand:         int -> int
  in expression:
    inc dbl

- inc dbl 5;
stdIn:1.2-24.1 Error: operator and operand don't agree [tycon mismatch]
  operator domain: int
  operand:         int -> int
  in expression:
    inc dbl