From bf6a337a5f943ed69e3f7f3ba0890c28365b0c64 Mon Sep 17 00:00:00 2001
From: Yuichi Nishiwaki <yuichi.nishiwaki@gmail.com>
Date: Tue, 26 Nov 2013 02:42:13 -0800
Subject: [PATCH] add pic_cxxr functions

---
 include/picrin/pair.h |  5 +++++
 src/pair.c            | 24 ++++++++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/include/picrin/pair.h b/include/picrin/pair.h
index 28c722bf..5fd18e62 100644
--- a/include/picrin/pair.h
+++ b/include/picrin/pair.h
@@ -15,4 +15,9 @@ pic_value pic_reverse(pic_state *, pic_value);
 pic_value pic_assq(pic_state *, pic_value key, pic_value assoc);
 pic_value pic_acons(pic_state *, pic_value key, pic_value val, pic_value assoc);
 
+pic_value pic_caar(pic_state *, pic_value);
+pic_value pic_cadr(pic_state *, pic_value);
+pic_value pic_cdar(pic_state *, pic_value);
+pic_value pic_cddr(pic_state *, pic_value);
+
 #endif
diff --git a/src/pair.c b/src/pair.c
index c1c78af1..193d4c77 100644
--- a/src/pair.c
+++ b/src/pair.c
@@ -134,6 +134,30 @@ pic_acons(pic_state *pic, pic_value key, pic_value val, pic_value assoc)
   return pic_cons(pic, pic_cons(pic, key, val), assoc);
 }
 
+pic_value
+pic_caar(pic_state *pic, pic_value v)
+{
+  return pic_car(pic, pic_car(pic, v));
+}
+
+pic_value
+pic_cadr(pic_state *pic, pic_value v)
+{
+  return pic_car(pic, pic_cdr(pic, v));
+}
+
+pic_value
+pic_cdar(pic_state *pic, pic_value v)
+{
+  return pic_cdr(pic, pic_car(pic, v));
+}
+
+pic_value
+pic_cddr(pic_state *pic, pic_value v)
+{
+  return pic_cdr(pic, pic_cdr(pic, v));
+}
+
 static pic_value
 pic_pair_pair_p(pic_state *pic)
 {