Python interface

[tillmo]

Build a python interface, using e.g. hyphen. Start with the core #2107 API #1790. The python interface could be used to interface Hets with https://github.com/gavel-tool and to build new interfaces, like a new GUI.

[b-gehrke]

Notes for hyphen

Building it:

• A PR prepares an automatic build for debian
  • not yet approved, but being actively review
• Systemwide installation not included
  • Build setup.py for local pip installation?
  • Extend import path env variable PYTHONPATH to build dir?
  • Symlinking build dir to python import paths?

Things to keep in mind:

• Parent modules
  • In python, when we import a module a.b.c, we necessarily also import the packages a and a.b first
  • In Haskell those package must not exist
  • Such packages must be added to hyphen.importing.EXPECTED_EMPTY manually
  • For example in Hets the Common namespace

Library

• Hyphen loads installed modules or source files.

In general, the preferred way of accessing Haskell code from Python via hyphen is to install the Haskell code as a ghc-pkg visible library; such libraries can always be directly imported into Python with hyphen (as we have been doing so far).

• Hets needs to be library as well (at least parts needed for core API)

[b-gehrke]

Is building a GUI still the best case? Do a quick research for a framework e.g. Gtk/GI, Qt. Preference is on Gtk