%{
  open Ast
%}

%token <int>    INT
%token <bool>   BOOL
%token <float>  FLOAT
%token <string> VAR
%token <string> OPER
%token LET EQ IN
%token IF THEN ELSE
%token LPAREN RPAREN BEGIN END
%token LBRACKET RBRACKET
%token PIPE
%token SEMISEMI SEMI COMMA
%token EOF

%start <Ast.ast list> main

%%

main:
  | expr SEMISEMI main { $1 :: $3 }
  | expr EOF           { [$1] }
  | EOF                { [] }
  ;

simple_expr:
  | INT
    { Int $1 }
  | FLOAT
    { Float $1 }
  | BOOL
    { Bool $1 }
  | VAR
    { Var $1 }
  | LPAREN expr RPAREN
    { $2 }
  | BEGIN expr END
    { $2 }
  | LBRACKET separated_list(SEMI, avg_expr) RBRACKET
    { List $2 }
  ;

avg_expr:
  | simple_expr { $1 }
  | call        { $1 }
  ;

expr:
  | avg_expr
    { $1 }
  | IF c = avg_expr THEN t = expr ELSE e = expr
    { If (c, t, e) }
  | LET b = bindings IN e = expr
    { Let (b, e) }
  | LET PIPE b = bindings IN e = expr
    { Let (b, e) }
  | tuple
    { Tuple $1 }
  ;

tuple:
  rev_tuple { List.rev $1 };

rev_tuple:
  | rev_tuple COMMA avg_expr
    { $3 :: $1 }
  | avg_expr COMMA avg_expr
    { [$3; $1] }
  ;

call:
  | avg_expr simple_expr
    { Call ($1, $2) }
  | e = avg_expr; o = OPER; f = avg_expr
    { Call (Call (Var ("(" ^ o ^ ")"), e), f) };
  ;

bindings:
  b = separated_list(PIPE, binding) { b }
  ;

binding:
  v = VAR; EQ; e = expr { (v, e) }
  ;