1. make \n inside macro argument angles terminate the argument and the macro expansion.
2. If missing ">", have parse error msg give better line number.
3. show full address in listing?
4. .deassign symbol
5. able to concate strings to make symbol names i.e. sym_'numsym'
6. macro and symbol exists checkers
7. say .quad x, then later x = . + ~~~ produces "x is sym and label error"
8. ".if b" and ".if nb" require <> for macro arg names
9. support delim style ^_~~~~~~_
10. ".endx" checking stack
11. Add more location info to absolute expression checker.
12. .pragma support for macro 'arg' use checking
13. eliminate requirement that a .mar file must end with \n
14. support \n,\t,.. in ASCII strings
15. .byte, .word support
16. .local symbol (note: still have the ?sym idea half implemented)
17. put error/warning messages in listing also
18. redirect .do_cmd info to listing?
19. HAL pixie idea (keeps track of how much time in each macro, # of calls, etc.)
20. HAL debugger idea (Allows breakpoints around macro calls, shown stack, symbol table, etc.)
21. Increase performance by doing multiple "skipargck" lines instead of just one
22. Delay if body preprocessing until executing it. (%extract uses symbol set in body)
23. nesting macro definitions and still using "'" in nested def arg's
24. %locate(<sub_text>, arg_name, start_pos)  -> arg_name wrong -> no error msg
25. %locate(<sub_text>, arg_name, start_pos)  -> no checking arg3 is a symbol
26. Floating point data types
27. Logical operators (use for complicated if conditions)