ENH: Add LLDB pretty printers for a few SIMPLNX classes.

[imikejackson]

• More to come later

There is a bit of setup that one must do in order to get LLDB to use these pretty
printers. Namely create a file called .lldbinit at the top level of your home
directory and put the following code in it:

command script import /Users/${USER}/Workspace1/simplnx/scripts/lldb_pretty_printers/data_path_pretty_printer.py

command script import /Users/${USER}/Workspace1/simplnx/scripts/lldb_pretty_printers/nx_core_array_pretty_printer.py

Where you will need to adjust the path to the actual python files based on how you have your environment setup.

[JDuffeyBQ]

We could combine all pretty printers into one package so that you only have one import to do for lldb. It would also let use share utility code between printers.

[JDuffeyBQ]

This uses the libc++ implementation which means it won't work with libstdc++ which is typical when using clang and lldb on linux.

[imikejackson]

What is the other option?

[JDuffeyBQ]

I have this script for testing:

nxprinter.py

import lldb

def data_path_summary(valobj: lldb.SBValue, internal_dict: dict) -> str:
  path_valobj: lldb.SBValue = valobj.GetChildMemberWithName('m_Path')

  elements = []
  element: lldb.SBValue
  for element in path_valobj:
    str_val: str = element.GetSummary()
    if str_val is None:
      str_val = '<NULL>'
    else:
      if len(str_val) >= 2 and str_val.startswith('"') and str_val.endswith('"'):
        str_val = str_val[1:-1]
    elements.append(str_val)

  return f"\"{'/'.join(elements)}\""

def array_summary(valobj: lldb.SBValue, internal_dict: dict) -> str:
  array_valobj: lldb.SBValue = valobj.GetChildMemberWithName('m_Array')

  # should "_M_elems" for libstdc++ and "__elems" for libc++
  std_array_elements: lldb.SBValue = array_valobj.child[0]

  if std_array_elements is None:
    return '<unavailable>'

  elements = []
  element: lldb.SBValue
  for element in std_array_elements:
    elem_value = element.GetValue()
    if elem_value is None:
      elem_value = element.GetSummary()
    if elem_value is None:
      elem_value = '<unavailable>'
    elements.append(elem_value)

  return f"({', '.join(elements)})"


def add_type_summary(debugger: lldb.SBDebugger, func_name: str, type_name: str, type_name_is_regex: bool = False) -> None:
  regex_flag = '-x' if type_name_is_regex else ''
  debugger.HandleCommand(
    f'type summary add -F nxprinter.{func_name} {regex_flag} "{type_name}"'
  )

def __lldb_init_module(debugger: lldb.SBDebugger, internal_dict: dict):
  add_type_summary(debugger, 'data_path_summary', 'nx::core::DataPath')
  add_type_summary(debugger, 'array_summary', 'nx::core::Array<.*,.*>', type_name_is_regex=True)