New Lisp feature: param list expander.

* eval.c (pm_table): New static variable.
(expand_param_macro): New static function.
(expand_params): Expand parameter list macros via
expand_param_macro.
(eval_init): gc-protect pm_table and initialize it.
Register *param-macro* variable.

* lisplib.v (pmac_set_entries, pmac_instantiate): New static
functions.
(lisplib_init): Register autoloading of pmac.tl via new
functions.

* share/txr/stdlib/pmac.tl: New file.

* txr.1: Notes under defun, lambds, flet/labels and defmacro
about the existence of parameter macros which add to
the syntax. New Parameter List Macros section.
Documented *param-macro* and define-param-expander.

1 files changed, 17 insertions, 0 deletions

diff --git a/lisplib.c b/lisplib.c
index 2423274a..9d0472e4 100644
--- a/lisplib.c
+++ b/lisplib.c
@@ -465,6 +465,22 @@ static val tagbody_instantiate(val set_fun)
   return nil;
 }
 
+static val pmac_set_entries(val dlt, val fun)
+{
+  val name[] = {
+    lit("define-param-expander"), nil
+  };
+  set_dlt_entries(dlt, name, fun);
+  return nil;
+}
+
+static val pmac_instantiate(val set_fun)
+{
+  funcall1(set_fun, nil);
+  load(format(nil, lit("~apmac.tl"), stdlib_path, nao));
+  return nil;
+}
+
 val dlt_register(val dlt,
                  val (*instantiate)(val),
                  val (*set_entries)(val, val))
@@ -501,6 +517,7 @@ void lisplib_init(void)
   dlt_register(dl_table, package_instantiate, package_set_entries);
   dlt_register(dl_table, getput_instantiate, getput_set_entries);
   dlt_register(dl_table, tagbody_instantiate, tagbody_set_entries);
+  dlt_register(dl_table, pmac_instantiate, pmac_set_entries);
 }
 
 val lisplib_try_load(val sym)