TODO

Little things
DONE	Change all make_foo() to make_foo_fill().
DONE	Verify all ASSERTs are needed.
DONE	Remove all #include <assert.h>.
DONE	Enable selftest.
DONE	Align function declarations in *.h.
DONE	Rename all "hdr" to "hobj".
DONE	Rename "normal pointer" to "heap object".
DONE	Rename check_obj() to CHECK_OBJ().
DONE	Refactor mem.h.
DONE	Make is_TYPE() inline by exporting the mem_ops_t structures.
DONE	Move is_null() and is_undefined() to their own files.
DONE	Find better names for EMPTY_LIST and UNDEFINED.
DONE	Make pair_car() and pair_cdr() inline.
DONE	Rename obj_procedure.{h,c} -> obj_proc.{h,c}
DONE	Rename proc.{h,c} -> prim.{h,c}
DONE	Write comments about DEFINE_* macros in prim.h.
DONE	Clean up obj_proc.h.
DONE	Implement get_who().
DONE	Rename all ASSERT to assert.
DONE	Rename RAISE to THROW.
DONE	Remove 2nd arg from CHECK and RAISE (aka THROW).
DONE	read.c should use &lexical, not &syntax.
DONE	Move apply_proc() from prim.c to eval.c.
DONE	Most exceptions shouldn't supply irritants.
drop	Move env from cont to dyn_env.
DONE	Split cont4 into cont3 and cont4. (cont4 and cont5?)
DONE	Define cont_proc_t in obj_proc.h and adjust function prototypes.
	There should be some field accessors in conditions.h.
DONE	Rewrite string->number in terms of char_to_number().
DONE	Remove #ifdef'd code in test.c
DONE	Remove #ifdef'd code in repl.c
DONE	Remove "#if OLD_PORTS" all over.
DONE	Remove "#if OLD_READER" in read.c.
DONE	Remove "#if OLD_SCANNER" in scan.c.
DONE	Remove read_stream() and yylex().
	Remove core_eval?
	Remove default-exception-handler in eval.c.

Heap
DONE	Implement records.
	Write comments about record layout.
DONE	Hook GC into setjmp (after eval).
drop	Reintroduce debug GC on every allocation.
	Automatically grow heap when out of memory.
	Implement transactional checks.
	Speed up environments.
	Speed up symbol lookup.
	Implement a mutability flag.  Possibly a separate mem_ops_t
	    for mutable types.

Data
DONE	Implement binding.
DONE	Implement continuation.
DONE	Implement procedure.
DONE	Implement condition as record.
DONE	Implement compound condition as record (not derived from condition)
	Check whether Unicode data is current rev.
	Rationalize wchar_t and char_t.

Eval
DONE	Design eval main loop.
DONE	  -- setjmp
DONE	  -- exceptions
DONE	  -- call/cc
	  -- multiple values
	  -- arg lists
	  -- nice calling convention for primitive procs