Semantics-Based Language Prototyping in SLANG

SLANG is a software for generating rapid prototype implementations of formal languages from their specifications. Your task is to study a particular formal language from literature (a simple programming language, a modeling language, a query language, any kind of domain-specific language). You define the syntax of the language,  give it a type system (in the form of a logical inference system), and a semantics (as a mathematical mapping from syntactic domains to semantic domains). You formalize the definitions in the SLANG software and thus generate a prototypical implementation of the language.