## Nummerical expression detection

If no specialized module is defined to detect nummerical expressions, the default behaviour is to recognize only numbers and codes written in digits (or mixing digits and non-digit characters).

If you want to recognize language dependent expressions (such as numbers expressed in words -e.g. ``one hundred thirthy-six''), you have to program a numbers_mylanguage class derived from abstract class numbers_module. Those classes are finite automata that recognize word sequences. An abstract class automat controls the sequence advance, so your derived class has little work to do apart from defining states and transitions for the automaton.

A good idea to start with this issue is having a look at the numbers_es, numbers_en, and numbers_ca classes. State/transition diagrams of those automata can be found in the directory `doc/diagrams`.