FTE: Bug in the regular expression compiler

[Sian Mountbatten <poenikatu@fastmail.co.uk>]

Dear People

I shall issue a reportbug, but I wanted to communicate with you more 
directly.
The test suite of regular expressions which the upstream author of FTE used
did not test properly one of the properties of the regular expression 
compiler.
It is true that it will successfully deal with the regular expression 
"{a|b|c|d|e}",
but it will NOT deal with "{ab|cd|ef|gh}". The only way to match alternative
strings which are more than one character long is to put each one between
braces: "{ab}|{cd}|{ef}".

I used the regular expression compiler and matcher code from FTE as the
basis of my Unicode regular expression library for use with Algol 68 
programs.
The code for the compiler is the same except that sets are specified 
differently.
The code for the matcher is more or less the same.

I have had to document the above compiler error as a feature of the library.
I did check with a working binary of xfte and discovered that the editor 
would
not search for alternative strings as described above.

Sincerely

--
Sian Mountbatten
Algol 68 Specialist