Start of fallback package list implementation.

* eval.c (eval_init): Register package-fallback-list and
set-package-fallback-list intrinsics.

* lib.c (package_fallback_list, set_package_fallback_list,
intern_fallback): New functions

* lib.h (package_fallback_list, set_package_fallback_list,
intern_fallback): Declared.

* parser.y (sym_helper): Slightly restructure function
so that the symbol interning is done separately in
the various cases. In the unqualified symbol case,
use intern_fallback to search the fallback list
of the current package.

* share/txr/stdlib/package.tl (defpackage): Implement
:fallback clause.

1 files changed, 4 insertions, 1 deletions

diff --git a/lib.h b/lib.h
index c55bd23c..e17f0668 100644
--- a/lib.h
+++ b/lib.h
@@ -785,7 +785,6 @@ val package_alist(void);
 val package_name(val package);
 val package_symbols(val package);
 val package_local_symbols(val package);
-val package_foreign_symbols(val package);
 val use_sym(val use_list, val package);
 val unuse_sym(val symbol, val package);
 val use_package(val use_list, val package);
@@ -793,6 +792,10 @@ val unuse_package(val unuse_list, val package);
 val intern(val str, val package);
 val unintern(val sym, val package);
 val rehome_sym(val sym, val package);
+val package_foreign_symbols(val package);
+val package_fallback_list(val package);
+val set_package_fallback_list(val package, val list);
+val intern_fallback(val str, val package);
 val symbolp(val sym);
 val symbol_name(val sym);
 val symbol_package(val sym);