Parser, Syntax Checker and Interpreter (PSCI) tools provide a simple means for parsing strings, perform syntax checking, and interpreting the parameters and/or values of the parsed strings. The basis for parsing and syntax checking is "rules-based", as opposed to constructing a complex syntax tree, which is data structure used by compiler writers. The "rules-based" structure is not as comprehensive as a syntax tree, but it is easier to implement and understand, and more than suffices for tool builders.