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Window Manager Languages

C
9wm, aewm, Firebox, and pretty much every other WM not named here
C++
aewm++, Clementine, IceWM, Jewel, miwm, pekwm, qlwm, tsubasa, wm2/wmx
Objective C
Interface WM, GNUStep
Eiffel
Framer (dead)
Haskell
XMonad
Java
JD4X, Looking Glass 3D, Puppet, Wizard Desktop
Lisp and variants (see also Scheme)
clfswm (Common Lisp), Eclipse (no longer available), gwm, sawfish (scripting, not whole WM(?)), StumpWM, XWEM (XEmacs Lisp)
Lua (for scripting, not the WM itself)
Ion, TrsWM
OCAML
GwML (nearly dead)
Pascal
fpcbol, MonkeyWM, XPde (Kylix)
Perl
PerlWM
Python
JoyWM (written using pygame), Parti, PLWM, PycaWM, PyWM, tritium, Whimsy
Ruby (for scripting, not the WM itself)
subtle
Scheme
Anarchy, scwm, wimpwm

https://gilesorr.com/wm/languages.html 
by giles