Metaprogramming Use Cases

Back to Metaprogramming -- language mechanisms

• Matrix of use case vs. metaprogramming technique: https://lobste.rs/s/aqdixr/gentle_introduction_compile_time#c_0cuoc9

• Notes about metaprogramming use cases, e.g. polyglot type systems and partial evaluation: https://www.reddit.com/r/ProgrammingLanguages/comments/73ldwj/the_lux_programming_language_strange_loop_2017/dnx309q/

  • Python 2.7 namedtuple
    • uses exec class_definition in namespace
  • Python 3.6 namedtuple
    • each field is an operator.itemgetter,
    • put on the class dict with with type() constructor
    • itemgetter calls:
      • item = PyTuple_GET_ITEM(ig->item, i);
      • val = PyObject_GetItem(obj, item);
  • interesting change!!!

• Oil Startup

  • core/id_kind.py -- every token/entity in OSH/Oil
  • Lexer State machine can be frozen
  • Lexer regexes can be compiled to gotos (a la re2c)
  • OPy parse tables using pgen2 (but not the Oil parser)
  • ASDL schema
  • Builtin Flags and Help could be frozen
  • misc regexes: to validate variable names, etc.