mcc.erl

apply f args = eval [f, ...[[QUOTE, a] | a <- args]...] []                                     % McCarthy-original-LISP-paper

eval e a | atom e    = case [v | [n, v] <- a, n == e] of {[v, ...]  ->  v}                     % first matching name's value 
         | otherwise =
  case e of
    [QUOTE,    x]    ->  x                                                                           % "expression"
    [FUNCTION, x]    ->  [FUNARG, x, a]                                                              % closure (new)
    [ATOM,     x]    ->  atom (eval x a)                                                 
    [EQ,    x, y]    ->  eval x a == eval y a                                            
    [CONS,  x, y]    ->  [eval x a, ...eval y a...]                                      
    [CAR,      x]    ->  case eval x a of {[v, ...]       ->  v }                                    % "expression", "value"
    [CDR,      x]    ->  case eval x a of {[_, ...vs...]  ->  vs}                                    % "values"
    [COND,           ...xs...]  ->  case [eval c a | [t, c] <- xs, eval t a] of {[v, ...]  ->  v}    % "test", "consequent"
    [[LAMBDA, b, c], ...xs...]  ->  eval c  [...[[n, eval x a] | n <- b | x <- xs]..., ...a...]      % "binds", "code"
    [[LABEL,  n, x], ...xs...]  ->  eval [x, ...xs...]  [[n, [LABEL, n, x]], ...a...]                % "name" 
    [[FUNARG, f, d], ...xs...]  ->  eval [f, ...[[QUOTE, eval x a] | x <- xs]...] d                  % closure (new)
    [x,              ...xs...]  ->  eval [eval x a, ...xs...] a                                      % fix the bug,
                                %%  eval [eval x a, ...[eval x a | x <- xs]...] a                    % args twice eval'd


apply [LAMBDA, [X,Y], [CONS, [CAR, X], Y]] [[A,B],[C,D]] =
eval [[LAMBDA, [X,Y], [CONS, [CAR, X], Y]], [QUOTE, [A,B]], [QUOTE, [C,D]]]  [] =
eval [CONS, [CAR, X], Y] [ [X, eval [QUOTE, [A,B]] []], [Y, eval [QUOTE, [C,D]] []], ...[]...] =
eval [CONS, [CAR, X], Y] [ [X, [A,B]], [Y, eval [QUOTE, [C,D]] []], ...[]...] =
eval [CONS, [CAR, X], Y] [ [X, [A,B]], [Y, [C,D]], ...[]...] =
eval [CONS, [CAR, X], Y] [ [X, [A,B]], [Y, [C,D]]] =
[eval [CAR, X]  [ [X, [A,B]], [Y, [C,D]]], ...eval Y  [ [X, [A,B]], [Y, [C,D]]]...] =
[eval [CAR, X]  [ [X, [A,B]], [Y, [C,D]]], ...[C,D]...] =
[eval [CAR, X]  [ [X, [A,B]], [Y, [C,D]]], C, D] =
[case eval X [ [X, [A,B]], [Y, [C,D]]] of [v, ...] -> v, C, D ] =
[case [A,B] of [v, ...] -> v, C, D ] =
[case [A, ...[B]...] of [A, ...] -> A, C, D ] =
[A, C, D].                                           %%%% YES!!! 





          eval e = \a -> case e of [QUOTE, x] -> x

          compile e = case e of [QUOTE, x] -> \a -> x