Contains functions used across packages 'QCA', 'DDIwR', and 'venn'. Interprets and translates SOP - Sum of Products expressions, for both binary and multi-value crisp sets, and extracts information (set names, set values) from those expressions. Other functions perform various other checks if possibly numeric (even if all numbers reside in a character vector) and coerce to numeric, or check if the numbers are whole. It also offers, among others, a highly flexible recoding function.
copied from cf-staging / r-admisc