New methods rplaca and rplacd.

* eval.c (eval_init): Register rplaca and rplacd using new
rplaca_s and rplacd_s symbol variables.

* lib.c (rplaca_s, rplacd_s): New symbol variables.
(rplaca): Handle struct object via rplaca method, if it has
one, otherwise lambda-set, if it has that, or else error
out.
(rplacd): Handle struct object via rplacd method.

* lib.h (rplaca_s, rplacd_s): Declared.

* txr.1: Documented rplaca and rplacd methods.

1 files changed, 2 insertions, 2 deletions

diff --git a/eval.c b/eval.c
index 0ffe88f4..81c62d11 100644
--- a/eval.c
+++ b/eval.c
@@ -5847,8 +5847,8 @@ void eval_init(void)
   reg_fun(intern(lit("lcons-fun"), user_package), func_n1(lcons_fun));
   reg_fun(car_s, car_f);
   reg_fun(cdr_s, cdr_f);
-  reg_fun(intern(lit("rplaca"), user_package), func_n2(rplaca));
-  reg_fun(intern(lit("rplacd"), user_package), func_n2(rplacd));
+  reg_fun(rplaca_s, func_n2(rplaca));
+  reg_fun(rplacd_s, func_n2(rplacd));
   reg_fun(intern(lit("rplaca"), system_package), func_n2(sys_rplaca));
   reg_fun(intern(lit("rplacd"), system_package), func_n2(sys_rplacd));
   reg_fun(intern(lit("first"), user_package), func_n1(car));