pub(all) enum Argument {
  Positional(Expr)
  Keyword(String, Expr)
  Star(Expr)
  DoubleStar(Expr)
} derive(Eq, Show, ToJson)

pub(all) enum AssignOp {
  PlusEq
  MinusEq
  StarEq
  SlashEq
  FloorDivEq
  PercentEq
  AmpEq
  PipeEq
  CaretEq
  LShiftEq
  RShiftEq
} derive(Eq, Show, ToJson)

pub(all) enum BinaryOp {
  Add
  Sub
  Mul
  Div
  FloorDiv
  Mod
  BitAnd
  BitOr
  BitXor
  LShift
  RShift
  Eq
  NotEq
  Lt
  Gt
  LtEq
  GtEq
  And
  Or
  In
  NotIn
} derive(Eq, Show, ToJson)

pub(all) enum CompClause {
  For(Expr, Expr)
  If(Expr)
} derive(Eq, Show, ToJson)

pub(all) enum Expr {
  NoneLiteral(Span)
  BoolLiteral(Bool, Span)
  IntLiteral(Int64, Span)
  StringLiteral(String, Span)
  Identifier(String, Span)
  UnaryOp(UnaryOp, Expr, Span)
  BinaryOp(Expr, BinaryOp, Expr, Span)
  IfExpr(Expr, Expr, Expr, Span)
  Call(Expr, Array[Argument], Span)
  Index(Expr, Expr, Span)
  Slice(Expr, Expr?, Expr?, Expr?, Span)
  Dot(Expr, String, Span)
  ListExpr(Array[Expr], Span)
  TupleExpr(Array[Expr], Span)
  DictExpr(Array[(Expr, Expr)], Span)
  ListComp(Expr, Array[CompClause], Span)
  DictComp(Expr, Expr, Array[CompClause], Span)
} derive(Eq, Show, ToJson)

pub(all) struct Parameter {
  name : String
  default : Expr?
} derive(Eq, Show, ToJson)

pub(all) struct Position {
  file : String
  line : Int
  column : Int
} derive(Eq, Show, ToJson)

pub(all) struct Span {
  start : Position
  end : Position
} derive(Eq, Show, ToJson)

pub(all) enum Stmt {
  Def(String, Array[Parameter], Array[Stmt], Span)
  If(Array[(Expr, Array[Stmt])], Array[Stmt]?, Span)
  For(Expr, Expr, Array[Stmt], Span)
  Return(Expr?, Span)
  Assign(Expr, AssignOp?, Expr, Span)
  Expr(Expr, Span)
  Load(String, Array[(String, String)], Span)
  Pass(Span)
  Break(Span)
  Continue(Span)
} derive(Eq, Show, ToJson)

pub(all) enum UnaryOp {
  Negate
  Pos
  BitNot
  LogNot
} derive(Eq, Show, ToJson)