A regular expression may be followed by a repetition operator in
order to indicate the number of times it may be repeated.
NOTE: Under Windows the operation "{X,Y}" has the syntax "{X-Y}"
because Windows will not accept the comma on a command line. Also, N
occurrences of an expression implies infinite repetitions but in
this program N represents the quantity 32768 which should
be a more than adequate substitute in real world text.
An expression followed by the operator "{X,Y}" indicates that
from X to Y occurrences of the expression are to be
located. This notation may take on several forms: "{X}"
means X occurrences of the expression, "{X,}" means
from X to N occurrences of the expression, and
"{,Y}" means from 0 (no occurrences) to Y
occurrences of the expression.
The `?' operator is a synonym for the operation "{0,1}".
Read as: "Zero or one occurrence."
The `*' operator is a synonym for the operation "{0,}".
Read as: "Zero or more occurrences."
The `+' operator is a synonym for the operation "{1,}".
Read as: "One or more occurrences."
The `=' operator is a synonym for the operation "{1}".
Read as: "One occurrence."