exception InvalidInputException of string
type token =
| Tok_RParen
| Tok_LParen
| Tok_Equal
| Tok_NotEqual
| Tok_Greater
| Tok_Less
| Tok_GreaterEqual
| Tok_LessEqual
| Tok_Or
| Tok_And
| Tok_Not
| Tok_If
| Tok_Then
| Tok_Else
| Tok_Add
| Tok_Sub
| Tok_Mult
| Tok_Div
| Tok_Concat
| Tok_Let
| Tok_Rec
| Tok_In
| Tok_Def
| Tok_Fun
| Tok_Arrow
| Tok_Int of int
| Tok_Bool of bool
| Tok_String of string
| Tok_ID of string
| Tok_DoubleSemi