ruby.py

import lldb

def ruby_value(val, dict):
  return 'ruby'

def __lldb_init_module(debugger, dict):
  print 'ready!'

session.log

~ ♢ lldb ruby
Current executable set to 'ruby' (x86_64).
(lldb) version
LLDB-112
(lldb) type summary add -P VALUE
Enter your Python command(s). Type 'DONE' to end.
def function (valobj,dict):
     return 'ruby'
     DONE
Segmentation fault: 11
~ ♢ lldb ruby
Current executable set to 'ruby' (x86_64).
(lldb) command script import ~/ruby.py
ready!
(lldb) type summary add -F ruby_value VALUE
(lldb) p (VALUE)0
(VALUE) $0 = 0
(lldb) type summary add --python-script "return 'ruby'" VALUE
(lldb) p (VALUE)0
(VALUE) $1 = 0 ruby