Extended regular expressions

Syntax guide for extended regular expressions in FCFORINVOICES — special [% %] brackets and word sets like DIGITS account for common OCR errors.

Formats are specified by means of extended regular expressions.

Extended regular expressions include the following additions:

1. Special brackets [% and %]. Characters inside the brackets are supplemented with popular OCR errors.
   For example, [%S%] may allow S, $, and 5.
2. Special words inside [%…%] for common character sets and OCR errors:
3. LETTERS - Capital Latin letters and characters commonly recognized as capital Latin letters
4. DIGITS - Digits and characters commonly recognized as digits
5. LETERSANDDIGITS - Capital Latin letters, digits, and characters commonly recognized as capital Latin letters and digits

For example, [%DIGITS%]{9} specifies nine consecutive digits or common OCR errors for digits, e.g. “OI234Sb7B9”.