;; TODO very WIP
(define-syntax
  "rust"
  :styles
  ("keyword" :fg 'red)
  ("symbol" :fg 'cyan)
  ("comment" :fg 'white :bold)
  ("string" :fg 'yellow)
  ("number" :fg 'cyan :bold)
  ("constant" :fg 'cyan :bold)
  :rules
  ;; Keywords
  (:keyword
    "use" "pub" "mod" "enum" "struct" "impl"
    "for" "=>" "->" "match" "for" "while" "loop"
    "if" "fn" "&mut" "&" "let" "where" "?"
    :category "keyword"
    )
  ;; Identifiers
  (:keyword
    "Rc" "RefCell" "Clone" "Copy" "PartialEq" "Eq"
    "PartialOrd" "Ord" "Debug" "Result" "Option"
    "bool" "i8" "i16" "i32" "i64" "i128" "u8" "u16"
    "u32" "u64" "u128" "str" "&str"
    "Self" "self" "&self" "&mut self" "Ok" "Err"
    :category "symbol"
    )
  (:keyword "true" "false" :category "constant")
  ;; strings
  (:regex "." "string" :prev-state 1)
  (:regex "[^\\\\]*\"" "string" :prev-state 1 :next-state 0)
  (:regex "\"" "string" :next-state 1)
  ;; numbers
  (:regex "(0x|0o|0b)?\\d+" "number")
  ;; Comments
  (:regex "//.*$" "comment")
  )