Hi everybody,
some time ago I stumbled over the problem that I missed a Qt version of some blocks. In particular I wanted to have a Qt numbersink and a Compass. Thus, I created them [1] with Qt designer and integrated them into a GR block. For now, they use Python. There are '.ui' files that have to be used to generate the '.py' files manually with pyuic4. Then they should install along with the other blocks.
Along with the Qt blocks I converted one of the gr-specest blocks 'DOA MUSIC' to the GR 3.7 API. The code I used for this is from Balint Seeber's gr-baz.
Also I wanted to have a Qt version of uhd_fft. But I didn't want to add code to the generated .py file. This lead to the creation of a 'Catch Function Result' block. It is a pure xml block which calls another blocks member function and stores the result into its own variable. I didn't want to use 'Function Probe' because I don't want to spawn a new thread which constantly calls a function.