Hi Antonio, last year I posted a tool to help working regular expressions with vfp you may like to test:
( Check attached image )

It allows to paste sample text , write & test regular expressions and save for later reference.
This version uses the rft control and solves for most cases the vb regex lack of functionallity to show sub matches position.

Note: This one works ok for most cases, but was a "cow-boy coded" version.. I already have a new one that is just a class that encapsulate the functionallity - no gui- that also solves getting proper matching positions for regex "aa(a)" testing "aaa" like exposed on http://stackoverflow.com/questions/27110305/how-to-get-the-position-of-a-javascript-regexp-sub-match that I hope to share soon.

You can download at:
https://vfpx.codeplex.com/wikipage?title=VfpRegexTool&referringTitle=Home