`scm_gc_mark', but doesn't mark the argument itself. defined
using an arrangement similar to that in eval.c: `scm_gc_mark' and
`scm_gc_mark_dependencies' are derived from the same "template"
by ugly preprocessor magic.
* gc.h: added prototype for `scm_gc_mark_dependencies'.
* init.c (scm_init_guile_1): call the renamed
`scm_init_guardians'.
* guardians.h: changed prototypes for `scm_make_guardian' and
`scm_init_guardians'.
* guardians.c (guardian_t): added new fields `greedy_p' and
`listed_p'.
(GUARDIAN_P): predicate that says whether its argument is a
guardian.
(GUARDIAN_GREEDY_P, GUARDIAN_LISTED_P): new predicates.
(greedy_guardians, sharing_guardians): new variables. hold the
greedy and sharing live guardian lists, respectively.
(first_live_guardian, current_link_field): removed.
(greedily_guarded_prop): new variable. holds the "is greedily
guarded" object property.
(self_centered_zombies): new variable. stores guarded objects
that are parts of cycles.
(add_to_live_list): new function, introduced to decouple marking a
guardian and adding it to the live list.
(guardian_mark): call `add_to_live_list'.
(guardian_print): print whether the guardian is greedy or not.
also change "live" and "zombie" to "reachable" and "unreachable"
respectively, to be less confusing.
(scm_guard): if the guardian is greedy, test whether the object is
already greedily marked. throw an error if so.
(scm_get_one_zombie): if the guardian is greedy, remove the
"greedily guarded" property from the object.
(scm_make_guardian): add a new optional boolean argument which
says whether the guardian is greedy or sharing.
(guardian_gc_init): init the new live lists.
(mark_dependencies): new function.
(mark_and_zombify): new function.
(guardian_zombify): reworked to support the new guardian
semantics. move some logic to `mark_dependencies' and
`mark_and_zombify'.
(whine_about_self_centered_zombies): new function. installed in
the `after-gc-hook' to complain about guarded objects which are
parts of cycles.
(scm_init_guardians): init the new stuff. renamed from
`scm_init_guardian'.
* values.c, values.h: new files. use a struct to contain multiple
values, similar to the previous Scheme-level implementation.
* Makefile.am: add values.c, values.h, values.x.
* continuations.c (continuation_apply): support R5RS multiple value
continuations.
* init.c: call scm_init_values.
* struct.h: define SCM_SET_STRUCT_PRINTER.
custom tc7 type. This will make it easier to support R5RS
multiple value continuations, without the use of a Scheme-level
wrapper.
* continuations.c (scm_tc16_continuation, continuation_mark,
continuation_free, continuation_print, continuation_apply):
new SMOB support.
(scm_make_continuation): new procedure, replaces scm_make_cont
with a different interface.
(copy_stack_and_call, scm_dynthrow, scm_init_continuations): rewritten.
(CHEAP_CONTINUATIONS): removed non-working code completely.
(scm_call_continuation): removed.
* continuations.h (struct scm_contregs): add num_stack_items and
stack fields. previously stack was stored following this struct:
use a tail array instead.
(SCM_CONTINUATIONP): new macro.
(SCM_CONTINUATION_LENGTH, SCM_SET_CONTINUATION_LENGTH):
rewritten.
(SCM_SET_CONTREGS): removed.
* tags.h: removed scm_tc7_contin (was tag 61).
* debug.c, gc.c, hash.c, print.c, procprop.c, procs.c:
removed scm_tc7_contin support.
* eval.c: use scm_make_continuation instead of scm_make_cont.
don't set jump buffers here. remove scm_tc7_contin support.
* init.c, root.c: create SMOB continuation for rootcont instead
of scm_tc7_contin. call scm_init_continuations before
scm_init_root.
* root.c: remove support for static jmpbuf. It's not used by
default and I broke it. create SMOB continuation for rootcont.
* stacks.c: use SCM_CONTINUATIONP.
