%%

optionnal_delimited(opening, X, closing):
    | v = delimited(opening, X, closing) { v }
    | v = X { v }

(* Redefine the arguments from expression here because we accept 
 * values without parens. *)
argument(X):
    | a =  optionnal_delimited(L_PAREN, arguments(X), R_PAREN) { a }
    | a = X { [ a ] }

(** At the opposite of an expression, an instruction does not return anything. *)
%public instruction:
    | s = single_instruction { s }

(** Action like act or if in a single line *)
%public inline_action:
    | a = onliner(ACT)
      { let loc, label, statements, _, _ = a in 
        let label = Analyzer.Expression.v label in
        Analyzer.Instruction.act loc ~label statements
      }
    | a = onliner(IF)
      else_opt = preceded(ELSE, instruction)?
      { let loc, expr, statements, loc_s, _body = a in 
        let elifs = []
        and else_ = match else_opt with 
          | None -> None
          | Some instructions -> Some ($loc(else_opt), [ instructions ]) in
        Analyzer.Instruction.if_
            loc 
            (loc_s, Analyzer.Expression.v expr, statements) 
            ~elifs
            ~else_
      }
    | a = onliner(IF)
      else_ = preceded(ELSE, inline_action)
      { let loc, expr, statements, loc_s, _body = a in 
        let elifs = []
        and else_ = Some ($loc(else_), [ else_ ]) in

        Analyzer.Instruction.if_
            loc 
            (loc_s, Analyzer.Expression.v expr, statements) 
            ~elifs
            ~else_
      }
single_instruction:
    | expr = expression
    { 
        let expr = Analyzer.Expression.v expr in
        Analyzer.Instruction.expression expr
    }
    | e = let_assignation   { e }
    | k = keyword
      args = argument(expression)
    {
        let args = List.map args ~f:(Analyzer.Expression.v) in
        Analyzer.Instruction.call $loc k args
    }

keyword:
    | k = KEYWORD  { k }

let_assignation:
    | assignation
      variable = variable
      op = assignation_operator
      value = expression 
    { 
        let variable = Helper.variable variable
        and value = Analyzer.Expression.v value in

        Analyzer.Instruction.assign $loc variable op value
    }

%inline assignation: 
    |
    | LET 
    | SET {}

assignation_operator:
    | EQUAL { T.Eq'  }
    | INCR  { T.Inc  }
    | DECR  { T.Decr }
    | MULT_EQUAL { T.Mult }
    | DIV_EQUAL { T.Div_assign }

inline_instruction:
    | hd = inline_instruction
      tl = single_instruction
      AMPERSAND+
      { tl :: hd }
    | 
      { [] }

final_inline_instruction:
    | hd = inline_instruction 
      tl = instruction  
    | hd = inline_instruction 
      tl = inline_action
      { tl :: hd }
    | hd = inline_instruction 
      COMMENT
      { (Analyzer.Instruction.comment $loc) :: hd }
    | hd = inline_instruction
      { hd }

onliner(TOKEN):
      | TOKEN
        e = expression
        COLUMN
        s = rev (final_inline_instruction)
      { $loc, e, s, $loc(s), None }