media-expr-grammar.ohm

MediaExpr {
  // Syntax Grammar
  Main        = Expression
  
  Expression  = LogicOr
  LogicOr     = LogicAnd ("or" LogicAnd)*
  LogicAnd    = Equality ("and" Equality)*
  Equality    = Comparison (("!=" | "==") Comparison)*
  Comparison  = Term ((">" | ">=" | "<" | "<=") Term)*
  
  Term        = Factor (("-" | "+") Factor)*
  Factor      = Exponent (("/" | "*" | "%") Exponent)*
  Exponent    = Unary ("^" Unary)*
  Unary       = ("!" | "-") Unary --unary
                  | Literal
  
  Literal     = "(" Expression ")" --parens
                  | bool
                  | number
                  | variable

  // Lexical Grammar
  bool       = "true" | "false"
  number     = decimal | whole
  decimal    = digit* "." digit+
  whole      = digit+
  
  variable   = letter alnum*

  /*
  alnum (an alpha-numeric character) = letter
      | digit
  digit (a digit) = "0".."9"
  letter (a letter) = lower
      | upper
      | unicodeLtmo
  */
}