Yes, it's a prototype editor with interactive example-based synthesis.

Barliman's synthesis can try to fill in "missing" sub-expressions in a Scheme definition. However, there is also a TDD component that might not be obvious. Barliman will attempt to run each test individually, even if the function has not been fully defined. That is, Barliman will attempt to synthesis a definition of the function to make each test pass. If Barliman can prove that there there is no way to fill in the function definition to make the test pass, the test will display an error message.

In other words, Barliman runs unit tests continually, and those tests can fail before you have finished defining the function being tested. Hopefully this feedback will let the programmer know that they are heading down the wrong path as soon as possible. Or, let the programmer double check the test, to make sure the test is correct.