DATA SCHEMATA IN PROGRAMMING LANGUAGE CONTRACTS

Systems and methods that integrate data type conversion(s) into a programming language, and describe external formats within a syntax thereof. A mapping component defines a declarative mapping from an external data format to one or more of its internal data types (e.g., expressing external data types in terms of source languages.) Moreover, a rule establishing component can define value-based rules, such as invariants to the external data format, wherein the schema declaration further defines data fields that make up the schema. Accordingly, by expressing rules in form of predicate logic (instead of imperative program logic) the subject innovation increase a likelihood that compilers can reason about the data.