syntax extensions
example
- syntax create nn: 'und' primary
- syntax epression append nn
function:
- create new syntax rules, reuse and modify existing syntax rules
- how to compile ast
ast handler
formal parameter may be ast: ast[person], togetether with a handler to continue processing
- name resolution (name for lower level, or new from this statement)
- nested design
compile-runt time pipeline
e.g. input a parially parsed/compiled prgram, output further processe file, after processing db description