/*
 * parser.mly
 * Parser for lambda
 * There should be 8 shift-reduce errors.
 */

%{
  (* This is where ocaml declarations go *)
  open Node 
%}

/* %token <int> INT */
%token <string> IDENT
%token LET EQUAL LAMBDA LPAREN RPAREN DOT EOF SEMI

%start program /* the entry point */

%type <Node.exp list> program



%%

program:
    declaration SEMI program { $3 }
  | expression SEMI program { $1::$3 }
  | SEMI program { $2 }
  | EOF { [] };

declaration:
    LET IDENT EQUAL expression
    {
      print_string "Parsed: ";
      print_exp $4;
      print_newline();
      global_env := ($2,bruijnize $4)::!global_env
    };

expression:
    simpexp
    { $1 }
  | application
    { $1 };

simpexp:
    IDENT
    { StrVar($1) }
/*  | INT
    { Num($1) } */
  | LPAREN expression RPAREN
    { $2 }
  | abstraction
    { $1 }
    

abstraction:
    LAMBDA IDENT DOT expression
    { Lambda($2,$4) };

application:
    application simpexp
    { Apply($1,$2) }
  | simpexp simpexp
    { Apply($1,$2) }; 


%%

(* End of parser.mly *)