PHP has many built-in functions to validate numbers but they all expect input in computer format: 1234.56. I need to validate stuff like 1,234.56 (English) or 1.234,56 (Spanish), together with some typical attributes (accepted range, max number of decimals, etc.).

I started writing my own function but I soon got lost. It's easy to read the user input into a float variable but I want to be able to detect numbers with invalid formats like 1,23456.7 or 1..25.

Do you have any recommendation on the subject?

(Decimal and thousand characters are known beforehand and it's okay to hard-code digit groups as three, there's no need to cover Indian number format.)