This program can help you, when you are a beginner in Qt and in using of
regular expressions. You can plan with this program your regular expressions
for your applications. Run the program, and use it easy. It contains only
two fields for editing. The top field is a LineEdit. Here you can edit
the regular expression, what you need. The bottom field a TextEdit object.
This is a checker (tester) field. Here you can check your edited regular
expression. The apperared text will be coloured. The meaning of character
colours: green - valid chars; blue - intermediate state between valid and
bad states, red - not acceptable chars.