Seed7

Seed7 is an extensible, general-purpose programming language designed by Thomas Mertes and released as open source in 2005. Its defining idea is that the syntax and semantics of the language are not hard-coded: a programmer can define new statements and operator symbols in Seed7 itself, using a syntax description notation and ordinary Seed7 functions, so that even arrays, hash maps and structs are ordinary library types rather than built-in features. The language is statically typed, supports imperative, object-oriented and generic programming with multiple dispatch and operator overloading, and omits macros, pointers and manual memory management. It descends from Mertes's earlier extensible language MASTER and its interpreter HAL, begun in 1989. The Seed7 project ships both an interpreter and a compiler that translates programs to C, together with a large portable library covering networking, graphics, databases and its own implementation of Transport Layer Security.