Neko

If you're looking for an interpreter and programming language that provides a common runtime for multiple languages, you might want to consider Neko. This programming language is designed with ease of use in mind, although it's not recommended to program directly in Neko. Instead, you can use Neko as a runtime to compile, run, and access libraries after writing a generator from your preferred language.

Neko is particularly useful for language designers who want to focus on design and reuse an already well-designed runtime, as well as existing libraries for accessing different features such as network, databases, filesystem, and xml. The language's syntax is created with "easy to parse" and "easy to generate" principles, which means it is not particularly designed to be written by hand by a programmer, but rather to be generated from a higher-level language. For example, you could write a PHP-to-Neko or Java-to-Neko generator that generates equivalent code, but uses Neko syntax and semantics.

The syntax of Neko is particularly noteworthy; there are no multiple levels of expression as in C, and every statement is also an expression. This means that constructs that are not possible in other languages are enabled, e.g., return if (x) { ... } else { ... }. This makes it easier to generate Neko syntax from functional languages.

The syntax is parsed using a lightweight left-to-right LL(1) parser, which means that after reading a token Neko has enough information to know which expression it will produce; this enables a very lightweight parser that can easily be improved without creating ambiguities. The latest version of Neko includes small bug fixes and new APIs for multithread programming (mutexes, deque, and TLS).