================================================================================
Escape Sequence - simple
================================================================================

echo \a \e \f \n \r \t \v
echo \1 \11 \111
echo \x \x9 \x09 \X \X9 \x09
echo \u \u9 \u09 \u009 \u0009
echo \U \U9 \U09 \U009 \U0009 \U00009 \U000009 \U0000009 \U00000009
echo \c \cy \ci \cI

--------------------------------------------------------------------------------

(program
  (command
    name: (word)
    argument: (escape_sequence)
    argument: (escape_sequence)
    argument: (escape_sequence)
    argument: (escape_sequence)
    argument: (escape_sequence)
    argument: (escape_sequence)
    argument: (escape_sequence))
  (command
    name: (word)
    argument: (escape_sequence)
    argument: (escape_sequence)
    argument: (escape_sequence))
  (command
    name: (word)
    argument: (escape_sequence)
    argument: (escape_sequence)
    argument: (escape_sequence)
    argument: (escape_sequence)
    argument: (escape_sequence)
    argument: (escape_sequence))
  (command
    name: (word)
    argument: (escape_sequence)
    argument: (escape_sequence)
    argument: (escape_sequence)
    argument: (escape_sequence)
    argument: (escape_sequence))
  (command
    name: (word)
    argument: (escape_sequence)
    argument: (escape_sequence)
    argument: (escape_sequence)
    argument: (escape_sequence)
    argument: (escape_sequence)
    argument: (escape_sequence)
    argument: (escape_sequence)
    argument: (escape_sequence)
    argument: (escape_sequence))
  (command
    name: (word)
    argument: (escape_sequence)
    argument: (escape_sequence)
    argument: (escape_sequence)
    argument: (escape_sequence)))
