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, 8 insertions, 5 deletions

diff --git a/stream.h b/stream.h
index 254b5cf4..04cdeb26 100644
--- a/stream.h
+++ b/stream.h
@@ -47,7 +47,13 @@ struct strm_ops {
   val (*set_prop)(val, val ind, val);
 };
 
-extern val std_input, std_output, std_debug, std_error, std_null;
+#define std_input (*lookup_var_l(nil, stdin_s))
+#define std_output (*lookup_var_l(nil, stdout_s))
+#define std_debug (*lookup_var_l(nil, stddebug_s))
+#define std_error (*lookup_var_l(nil, stderr_s))
+#define std_null (*lookup_var_l(nil, stdnull_s))
+val *lookup_var_l(val env, val sym);
+
 extern val output_produced;
 
 extern val dev_k, ino_k, mode_k, nlink_k, uid_k;
@@ -56,10 +62,7 @@ extern val atime_k, mtime_k, ctime_k;
 extern val from_start_k, from_current_k, from_end_k;
 extern val real_time_k, name_k;
 
-extern val s_ifmt, s_ifsock, s_iflnk, s_ifreg, s_ifblk, s_ifdir;
-extern val s_ifchr, s_ififo, s_isuid, s_isgid, s_isvtx, s_irwxu;
-extern val s_irusr, s_iwusr, s_ixusr, s_irwxg, s_irgrp, s_iwgrp;
-extern val s_ixgrp, s_irwxo, s_iroth, s_iwoth, s_ixoth;
+val stdin_s, stdout_s, stddebug_s, stderr_s, stdnull_s;
 
 val make_null_stream(void);
 val make_stdio_stream(FILE *, val descr);