use nreverse

3 files changed, 17 insertions, 2 deletions

diff --git a/src/interp.c b/src/interp.c
index a8c9ad7..befd28d 100644
--- a/src/interp.c
+++ b/src/interp.c
@@ -566,6 +566,20 @@ SExpRef lisp_reverse(Interp *interp, SExpRef lst) {
     return ret;
 }
 
+SExpRef lisp_nreverse(Interp *interp, SExpRef lst) {
+    SExpRef prev = NIL;
+    SExpRef cur = lst;
+    SExpRef next_node;
+
+    while (!NILP(cur)) {
+        next_node = CDR(cur);
+        REF(cur)->pair.cdr = prev;
+        prev = cur;
+        cur = next_node;
+    }
+    return prev;
+}
+
 SExpRef lisp_eval_args(Interp *interp, SExpRef args) {
     SExpRef ret = interp->nil;
     SExpRef cur = args;
@@ -583,7 +597,7 @@ SExpRef lisp_eval_args(Interp *interp, SExpRef args) {
         ret = CONS(evalres, ret);
         cur = CDR(cur);
     }
-    ret = lisp_reverse(interp, ret);
+    ret = lisp_nreverse(interp, ret);
 end:
     Interp_gc(interp, ret);
     return ret;
diff --git a/src/interp.h b/src/interp.h
index 36fd1e0..d4940e0 100644
--- a/src/interp.h
+++ b/src/interp.h
@@ -77,6 +77,7 @@ SExpRef Interp_load_file(Interp *interp, const char *filename);
 
 const char* lisp_to_string(Interp *interp, SExpRef val);
 SExpRef lisp_macroexpand1(Interp *interp, SExpRef macro, SExpRef args);
+SExpRef lisp_nreverse(Interp *interp, SExpRef lst);
 SExpRef lisp_reverse(Interp *interp, SExpRef lst);
 void lisp_defun(Interp *interp, SExpRef name, SExpRef val);
 void lisp_defvar(Interp *interp, SExpRef name, SExpRef val);
diff --git a/src/primitives.c b/src/primitives.c
index 1c0d1e3..b66f357 100644
--- a/src/primitives.c
+++ b/src/primitives.c
@@ -453,7 +453,7 @@ static SExpRef quasi_on_list(Interp *interp, SExpRef lst) {
         iter = CDR(iter);
     }
 
-    return lisp_reverse(interp, newlst);
+    return lisp_nreverse(interp, newlst);
 }
 
 SExpRef primitive_quasi(Interp *interp, SExpRef args, bool istail) {