Local declaration with nameref

[uzibalqa]

I have the following bash function that is not making any sense to me,
finding it quite confusing.

After the function call, when I echo "$signal", I are printing the value of the
variable signal that was passed as an argument to the function. Since the 
function
modifies the value of _signal which is passed by reference to signal outside of 
the function, the value of signal is also changed to "SUBSCRIPT".

Yet, the variable gives the impression that it has local context only inside 
the function.


marin () {
  local -n _signal="$1" _modes="$2"
  [[ :"$_modes": != *:"$_signal":* ]] && _signal='SUBSCRIPT'
}

modes="ITERATE:COUNTER"
signal="foo"
marin signal modes
echo "$signal"