awk: new feature, res variable.

The res variable captures the specific value of the
condition expression, making it available to the action.

* autoload.c (awk_set_entries): Intern the res symbol

* stdlib/awk.tl (awk): Instead of generating the condition-action
into a simple when, we use whenlet to also bind the res variable.

* tests/015/awk-res.tl: New file.

* txr.1: Documented.

* stdlib/doc-syms.tl: Updated.

1 files changed, 1 insertions, 0 deletions

diff --git a/autoload.c b/autoload.c
index 30d388ba..72e89e9e 100644
--- a/autoload.c
+++ b/autoload.c
@@ -352,6 +352,7 @@ static val awk_set_entries(val fun)
     lit("<-"), lit("!>"), lit("<!"), lit("prn"),
     lit("i"), lit("o"), lit("x"), lit("b"), lit("c"), lit("r"),
     lit("iz"), lit("oz"), lit("xz"), lit("bz"), lit("cz"), lit("rz"),
+    lit("res"),
     nil
   };
   autoload_sys_set(al_struct, sys_sname, fun);