ddd 'Can't open display' on macos

Question

I'd like to debug a cython program (following this tutorial). To do so, I need ddd. So, I run the following command: brew install ddd but when the command ddd python3 leads to:

Error: Can't open display:

What can I do to have more information on what is the problem and identify where it is coming from ?

Answer 1

I don't use ddd, but it appears to need X11, i.e. an X Windows server. As Macs no longer come with an X11 server, you'd need to install XQuartz which you can obtain here.

Also, I would imagine you need:

brew install ddd 

rather than:

brew uninstall ddd