From d9e47bdd052a1f68ac526cfc0ac48a02727e9065 Mon Sep 17 00:00:00 2001
From: Yuichi Nishiwaki <yuichi.nishiwaki@gmail.com>
Date: Thu, 17 Oct 2013 17:54:28 +0900
Subject: [PATCH] add begin syntax

---
 include/picrin.h |  3 ++-
 src/state.c      |  1 +
 src/vm.c         | 12 +++++++++++-
 3 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/include/picrin.h b/include/picrin.h
index 6ae5eef3..a83b1df9 100644
--- a/include/picrin.h
+++ b/include/picrin.h
@@ -23,7 +23,8 @@ typedef struct {
   pic_callinfo *ci;
   pic_callinfo *cibase, *ciend;
 
-  pic_value sDEFINE, sLAMBDA, sIF, sCONS;
+  pic_value sDEFINE, sLAMBDA, sIF, sBEGIN;
+  pic_value sCONS;
   pic_value sADD, sSUB, sMUL, sDIV;
   struct pic_env *global_env;
 
diff --git a/src/state.c b/src/state.c
index 48740e64..58ccbc47 100644
--- a/src/state.c
+++ b/src/state.c
@@ -48,6 +48,7 @@ pic_open()
   pic->sDEFINE = pic_intern_cstr(pic, "define");
   pic->sLAMBDA = pic_intern_cstr(pic, "lambda");
   pic->sIF = pic_intern_cstr(pic, "if");
+  pic->sBEGIN = pic_intern_cstr(pic, "begin");
   pic->sCONS = pic_intern_cstr(pic, "cons");
   pic->sADD = pic_intern_cstr(pic, "+");
   pic->sSUB = pic_intern_cstr(pic, "-");
diff --git a/src/vm.c b/src/vm.c
index 90be78f0..910c2b73 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -227,11 +227,12 @@ static struct pic_irep *pic_gen_lambda(pic_state *, pic_value, struct pic_env *)
 static void
 pic_gen(pic_state *pic, struct pic_irep *irep, pic_value obj, struct pic_env *env)
 {
-  pic_value sDEFINE, sLAMBDA, sIF, sCONS, sADD, sSUB, sMUL, sDIV;
+  pic_value sDEFINE, sLAMBDA, sIF, sBEGIN, sCONS, sADD, sSUB, sMUL, sDIV;
 
   sDEFINE = pic->sDEFINE;
   sLAMBDA = pic->sLAMBDA;
   sIF = pic->sIF;
+  sBEGIN = pic->sBEGIN;
   sCONS = pic->sCONS;
   sADD = pic->sADD;
   sSUB = pic->sSUB;
@@ -309,6 +310,15 @@ pic_gen(pic_state *pic, struct pic_irep *irep, pic_value obj, struct pic_env *en
       irep->code[t].u.i = irep->clen - t;
       break;
     }
+    else if (pic_eq_p(pic, proc, sBEGIN)) {
+      pic_value v, seq;
+
+      seq = pic_cdr(pic, obj);
+      for (v = seq; ! pic_nil_p(v); v = pic_cdr(pic, v)) {
+	pic_gen(pic, irep, pic_car(pic, v), env);
+      }
+      break;
+    }
     else if (pic_eq_p(pic, proc, sCONS)) {
       pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, pic_cdr(pic, obj))), env);
       pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, obj)), env);