(* code to be copied in the scanner module *)
(*
*)
%{
  open Types
%}

(* tokens *)
%token MAIN DEF WITH INPUT OUTPUT AS SKIP ASSIGNMENT SEQUENCE IF THEN ELSE WHILE
%token FOR DO COMMA LEFTPAR RIGHTPAR
%token PLUS MINUS TIMES DIVISION MODULO POWER POWERMOD RAND
%token BAND BOR BNOT BCMP BCMPLESS BCMPLESSEQ BCMPGREATER BCMPGREATEREQ
%token <bool> BOOL
%token <int> INT
%token <string> VARIABLE
%token EOF

%type <c_exp> cexpp
%type <b_exp> bexpp
%type <a_exp> aexpp
%type <p_exp> prg

(* start nonterminal *)
%start prg

(* associativity in order of precedence *)
%left lowest
%left SEQUENCE
%left ELSE
%left PLUS MINUS BOR BAND
%left BNOT
%left DIVISION
%left MODULO
%left TIMES
%right POWER
%left DO

%%

(* grammar *)
prg:
  | DEF; MAIN; WITH; INPUT; a = VARIABLE; OUTPUT; b = VARIABLE; AS; t = cexpp; EOF
    {Main (a, b, t)}                   // def main with input a output b as t
cexpp:
  | SKIP {Skip}                        // skip
  | a = VARIABLE; ASSIGNMENT; body = aexpp
    {Assignment (a, body)}             // a := body
  | t1 = cexpp; SEQUENCE; t2 = cexpp %prec lowest
    {Sequence (t1, t2)}                // t1; t2
  | t = cexpp; SEQUENCE                {t} // t;
  | IF; guard = bexpp; THEN; body1 = cexpp; ELSE; body2 = cexpp
    {If (guard, body1, body2)}         // if ... then ... else ...
  | WHILE; guard = bexpp; DO; body = cexpp;
    {While (guard, body)}              // while ... do ...
  | FOR; LEFTPAR; ass = cexpp; COMMA; guard = bexpp; COMMA; iter = cexpp; RIGHTPAR;
         DO; body = cexpp;
    {For (ass, guard, iter, body)}     // for (..., ..., ...) do ...
  | LEFTPAR; t = cexpp; RIGHTPAR {t}   // (...)
bexpp:
  | b = BOOL                              {Boolean (b)} // true, false
  | b1 = bexpp; BAND; b2 = bexpp          {BAnd (b1, b2)} // &&
  | b1 = bexpp; BOR; b2 = bexpp           {BOr (b1, b2)} // ||
  | BNOT; b = bexpp                       {BNot (b)} // not
  | a1 = aexpp; BCMP; a2 = aexpp          {BCmp (a1, a2)} // ==
  | a1 = aexpp; BCMPLESS; a2 = aexpp      {BCmpLess (a1, a2)} // <
  | a1 = aexpp; BCMPLESSEQ; a2 = aexpp    {BCmpLessEq (a1, a2)} // <=
  | a1 = aexpp; BCMPGREATER; a2 = aexpp   {BCmpGreater (a1, a2)} // >
  | a1 = aexpp; BCMPGREATEREQ; a2 = aexpp {BCmpGreaterEq (a1, a2)} // >=
  | LEFTPAR; b = bexpp; RIGHTPAR          {b} // (b)
aexpp:
  | a = VARIABLE                          {Variable (a)}
  | i = INT                               {Integer (i)}
  | t1 = aexpp; PLUS; t2 = aexpp          {Plus (t1, t2)} // +
  | t1 = aexpp; MINUS; t2 = aexpp         {Minus (t1, t2)} // -
  | MINUS; i = INT                        {Integer (-i)}
  | t1 = aexpp; TIMES; t2 = aexpp         {Times (t1, t2)} // *
  | t1 = aexpp; DIVISION; t2 = aexpp      {Division (t1, t2)} // /
  | t1 = aexpp; MODULO; t2 = aexpp        {Modulo (t1, t2)} // %
  | t1 = aexpp; POWER; t2 = aexpp         {Power (t1, t2)} // ^
  | POWERMOD; LEFTPAR; t1 = aexpp; COMMA;
                       t2 = aexpp; COMMA;
                       t3 = aexpp; RIGHTPAR
    {PowerMod (t1, t2, t3)}               // powmod(..., ..., ...)
  | RAND; LEFTPAR; t = aexpp; RIGHTPAR    {Rand (t)} // rand()
  | LEFTPAR; a = aexpp; RIGHTPAR          {a} // (a)