trace: new parameter macro :trace for simple static tracing

Just add :trace to the head of the parameter list, and the
function is traced. No dynamic turning on and off though.

* autoload.c (trace_set_entries): Trigger autoload on :trace
keyword.

* stdlib/trace.tl (:trace): New parameter list expander.

* txr.1: Documented.

1 files changed, 4 insertions, 0 deletions

diff --git a/autoload.c b/autoload.c
index 86770c8a..84376173 100644
--- a/autoload.c
+++ b/autoload.c
@@ -405,9 +405,13 @@ static val trace_set_entries(val fun)
   val name[] = {
     lit("trace"), lit("untrace"), nil
   };
+  val kname[] = {
+    lit("trace"), nil
+  };
   autoload_sys_set(al_fun, sys_name, fun);
   autoload_set(al_var, vname, fun);
   autoload_set(al_fun, name, fun);
+  autoload_key_set(al_key, kname, fun);
   return nil;
 }