You cannot add characters to a string or delete characters from a string.
If you want a read an entire line from a file stream, then instantiate
the following pattern:
stream nextLine
If you want to determine a stream is empty, then instantiate the
following pattern:
stream atEnd
If you want to determine whether a string is empty, then instantiate one of
the following patterns:
string isEmpty
string notEmpty
If you want to extract a character from a string, then instantiate the
following pattern:
string at: index
If you want to read information from a string as though it were a stream,
then instantiate the following pattern to produce a stream, and then
read from the stream using, for example, nextWord.