Deprecate symbol properties.

* libguile/strings.c (scm_i_make_symbol): Remove 'props' argument.  Use
3 words instead of 'scm_double_cell'.
* libguile/strings.h: Adjust accordingly.
* libguile/symbols.c (scm_i_str2symbol, scm_i_str2uninterned_symbol):
Likewise.
(scm_symbol_fref, scm_symbol_pref, scm_symbol_fset_x,
scm_symbol_pset_x): Move to...
* libguile/deprecated.c: ... here.  Rewrite in terms of object
properties.
(symbol_function_slot, symbol_property_slot): New variables.
* libguile/symbols.h (SCM_SYMBOL_FUNC, SCM_SET_SYMBOL_FUNC)
(SCM_SYMBOL_PROPS, SCM_SET_SYMBOL_PROPS)
(scm_symbol_fref, scm_symbol_pref, scm_symbol_fset_x)
(scm_symbol_pset_x): Move to...
* libguile/deprecated.h: ... here.  Mark declarations as 'SCM_DEPRECATED'.
* module/system/base/types.scm (cell->object): Remove 'props' field for
%TC7-SYMBOL.
* doc/ref/api-data.texi (Symbol Props): Remove.
* NEWS: Update.

1 files changed, 8 insertions, 0 deletions

diff --git a/NEWS b/NEWS
index 17a4c3961..93eac87b8 100644
--- a/NEWS
+++ b/NEWS
@@ -175,6 +175,14 @@ SCM_SET_ARRAY_CONTIGUOUS_FLAG, SCM_CLR_ARRAY_CONTIGUOUS_FLAG,
 SCM_I_ARRAY_CONTP preprocessor interfaces, as they were internal and
 there is no longer a sensible way of using them.
 
+** Deprecate symbol properties
+
+Symbols used to have a "function slot" and a "property slot", inherited
+from Emacs Lisp and early Lisps, which one would access with
+'symbol-pref', 'symbol-fref', 'symbol-pset!', and 'symbol-fset!'.  These
+procedures have been discouraged in favor of object properties; they are
+now deprecated.  This saves a few words of memory per symbol.
+
 * Bug fixes
 
 ** Fix compilation of (ash x N), where N is a literal, at -O1 and below