Change in the design of how special variables work, to fix the broken

re-binding. C code now has to go through the dynamic environment lookup
to access things like *random-state*, or *stdout*.  As part of this,
I'm moving some intrinsic variable and function initializations out of
eval.c and into their respective modules.  Macros are are used to make
global variables look like ordinary C variables.  This is very similar
to the errno trick in POSIX threads implementations.

* eval.c (looup_var, lookup_var_l): Restructured to eliminate silly
goto, the cobjp handling is gone.
(reg_fun, reg_var): Internal function becomes external.
reg_var registers a simple cons cell binding now, without any
C pointer tricks to real C global variables.
(c_var_mark): Static function removed.
(c_var_ops): Static struct removed.
(eval_init): Numerous initializations for streams, syslog, rand,
signals and others moved to their respective modules.
The new symbol variables user_package_s, keyword_package_s
and system_package_s are interned here, and the variables are
created in a special way.

* eval.h (reg_var, reg_fun): Declared.

* gc.c (prot1): Added assert that the loc pointer isn't null.
This happened, and blew up during garbage collection.

* lib.c (system_package, keyword_package, user_package): Variables
removed these become macros.
(system_package_var, keyword_package_var, user_package_var): New
global variables.
(system_package_s, keyword_package_s, user_package_s): New
symbol globals.
(get_user_package, get_system_package, get_keyword_package): New
functions.
(obj_init): Protect new variables. Initialization order of modules
tweaked: the modules sig_init, stream_init, and rand_init are moved
after eval_init because they register variables.

* lib.h (keyword_package, system_pckage, user_package): Variables
turned into macros.
(system_package_var, keyword_package_var, user_package_var): Declared.
(system_package_s, keyword_package_s, user_package_s): Declared.
(get_user_package, get_system_package, get_keyword_package): Declared.

* rand.c (struct random_state): Renamed to struct rand_state to
avoid clash with new random_state macro.
(random_state): Global variable removed.
(random_state_s): New symbol global.
(make_state, rand32, make_random_state, random_fixnum, random):
Follow rename of struct random_state.

1 files changed, 9 insertions, 1 deletions

diff --git a/lib.h b/lib.h
index d2548e09..cf6b02e0 100644
--- a/lib.h
+++ b/lib.h
@@ -316,7 +316,12 @@ INLINE val chr(wchar_t ch)
 
 #define lit(strlit) lit_noex(strlit)
 
-extern val keyword_package, system_package, user_package;
+#define keyword_package (*get_keyword_package())
+#define user_package (*get_user_package())
+#define system_package (*get_system_package())
+
+extern val system_package_var, keyword_package_var, user_package_var;
+extern val keyword_package_s, system_package_s, user_package_s;
 extern val null_s, t, cons_s, str_s, chr_s, fixnum_sl;
 extern val sym_s, pkg_s, fun_s, vec_s;
 extern val stream_s, hash_s, hash_iter_s, lcons_s, lstr_s, cobj_s, cptr_s;
@@ -568,6 +573,9 @@ val symbolp(val sym);
 val symbol_name(val sym);
 val symbol_package(val sym);
 val keywordp(val sym);
+val *get_user_package(void);
+val *get_system_package(void);
+val *get_keyword_package(void);
 val func_f0(val, val (*fun)(val env));
 val func_f1(val, val (*fun)(val env, val));
 val func_f2(val, val (*fun)(val env, val, val));