Eidola

Eidola:

Eidola is a representation-independent, object-oriented, visual programming language.

Eidola is an experiment which takes a wild new approach to the structure and representation of programming languages. Traditional programming languages are heavily tied to their representation as textual source code, which is unfortunate -- pure text is a very poor notation system for the concepts of a high-level language. An Eidola program, however, exists independent of any representation; its "fundamental" form is as a set of carefully defined mathematical abstractions, opening the possibility of having many different notations. Representations of the language thus exist for the benefit of the programmer instead of the compiler, and freed from the constraints of text files, we can tackle the question of how to notate a program well.

Be warned: Eidola is a very large project its very early phases. It is still mostly theory and vaporware. Because there are no full-fledged notation systems for Eidola yet, you will not find any substantive code examples. Have your imagination warmed up and ready to go -- you're going to need it!

A programming language without a specified syntax, hmm...