TODO

TODO
----

While functional, there's a lot still to be added or considered.  This list is
not necessarily complete, and in some regards just acts as a scratch pad for me
to remember things that need doing.

### Medium priority

 * **ENDM** argument could match the opening MACRO if specified.
 * Check all symbols are valid.  After variable substitution (e.g., in macros),
   they might end up containing invalid characters.
 * Structs.
 * Functions.  I already have an expression evaluator, so why not?
 * Replace simple opcode strings with a new opcode node type - eliminate many
   strcasecmp()s.
 * **SET** should perhaps be incompatible with other assignments.

### Low priority

 * **INCLUDE** could push arguments as new positional variables.
 * **EQU** could permit any value, including lists.  A list could expand
   in-place somehow.
 * Should **DP** default to zero, not disabled?
 * Ability to specify maximum number of passes.
 * As it stands, section names need to be quoted - can this requirement be
   lifted?  Similarly when pasting macro args - maybe pass a simplified ID?
 * 6800, 6801, 6803 ISA support.
 * Support the extended syntax pseudo-ops from the Perl version.
 * For CoCo3 and others, destination addresses could usefully be outside the
   64K range.
 * The limitation on inclusion and macro expansion occurring in the first pass
   could be lifted.  Should just be able to clear all local label tables
   whenever an expansion occurs in a later pass, and then trigger another one.