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."