flowchart LR
  Start[Start]
  Stop[Stop]
  Start --> Mant([<tt>0</tt>..<tt>9</tt>])
  Mant --> Mant
  Mant --> E([<tt>E</tt> / <tt>e</tt>])
  Mant --> Dot([<tt>.</tt>])
  Dot --> Frac([<tt>0</tt>..<tt>9</tt>])
  Frac --> Stop
  Frac --> E
  Frac --> Frac
  E --> Sign([<tt>+</tt> / <tt>-</tt>])
  E --> Exp([<tt>0</tt>..<tt>9</tt>])
  Sign --> Exp
  Exp --> Exp
  Exp --> Stop
  Mant --> Stop