PR #3513, developed by @SaidkhojaIftikhor, has been stuck for some time awaiting tests. This is the first of three PRs to replace that one. This PR also allows the use of slash as a thousands separator or decimal separator or currency symbol. These are, of course, very unusual situations; the main reason to support them is so that PhpSpreadsheet code will not crash when users set those options. New Calculation/Engine and AdvancedValueBinder tests confirm these. While making these changes, a few errors were found in AdvancedValueBinder and Calculation/Engine/FormattedNumber, e.g. currencies weren't parsed correctly when period was used as the group separator and comma as the decimal separator. Tests have been added for those situations.
oleibman