//------------------------------------------
// OMNOM LISP
//------------------------------------------


// ##################
// ###   Tokens   ###
// ##################

        $ ";[^\n]*";
        $ "[ \t\r\n]+";
        - "\d+[a-zA-Z]+";

symbol  = "[a-zA-Z][\w-]*\??|=|\+|-|\*|/|<|>";
string  = "\"([^\\\"]*(\\.)?)*\"";
int     = "\d+";
float   = "\d*\.\d+|\d+\.\d*";
bool    = "#[tf]";
quote   = "\'";
op      = "\(";
cp      = "\)";


// ###################
// ###   Symbols   ###
// ###################

INPUT       = EXPRESSION*;
EXPRESSION  = ATOM | LIST | LITERAL;
LITERAL     = $quote @EXPRESSION;
ATOM        = symbol | string | int | float | bool;
LIST        = $op EXPRESSION* $cp;

//------------------------------------------
// LISP CODE
//------------------------------------------

(define divides?
  (lambda (x y)
    (= (modulo y x) 0)))

(define divisors
  (lambda (x)
    (filter
      (lambda (y) (divides? y x))
      (range 2 (+ (sqrt x) 1)))))

(define prime?
  (lambda (x)
    (empty? (divisors x))))

(filter prime? (range 2 100))