From 53f76b7a474dab06648f6bbf5e063e52ae137dc2 Mon Sep 17 00:00:00 2001
From: Yuichi Nishiwaki <yuichi.nishiwaki@gmail.com>
Date: Tue, 3 Jun 2014 23:54:51 +0900
Subject: [PATCH] support renaming export

---
 src/lib.c   | 16 ++++++++++++++++
 src/macro.c | 24 ++++++++++++++++++++++--
 2 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/src/lib.c b/src/lib.c
index c33f694f..0cdcff73 100644
--- a/src/lib.c
+++ b/src/lib.c
@@ -97,3 +97,19 @@ pic_export(pic_state *pic, pic_sym sym)
 
   xh_put(&pic->lib->exports, sym, &rename);
 }
+
+void
+pic_export_as(pic_state *pic, pic_sym sym, pic_sym as)
+{
+  pic_sym rename;
+
+  if (! pic_find_rename(pic, pic->lib->senv, sym, &rename)) {
+    pic_errorf(pic, "export: symbol not defined %s", pic_symbol_name(pic, sym));
+  }
+
+#if DEBUG
+  printf("* exporting %s as %s\n", pic_symbol_name(pic, as), pic_symbol_name(pic, rename));
+#endif
+
+  xh_put(&pic->lib->exports, as, &rename);
+}
diff --git a/src/macro.c b/src/macro.c
index bcea0909..59e53c0c 100644
--- a/src/macro.c
+++ b/src/macro.c
@@ -267,14 +267,34 @@ macroexpand_import(pic_state *pic, pic_value expr)
 static pic_value
 macroexpand_export(pic_state *pic, pic_value expr)
 {
+  extern pic_value pic_export_as(pic_state *, pic_sym, pic_sym);
   pic_value spec;
+  pic_sym sRENAME, sym, as;
+
+  sRENAME = pic_intern_cstr(pic, "rename");
 
   pic_for_each (spec, pic_cdr(pic, expr)) {
-    if (! pic_sym_p(spec)) {
+    if (pic_sym_p(spec)) {
+      sym = as = pic_sym(spec);
+    }
+    else if (pic_list_p(spec) && pic_eq_p(pic_car(pic, spec), pic_sym_value(sRENAME))) {
+      if (pic_length(pic, spec) != 3) {
+        pic_error(pic, "syntax error");
+      }
+      if (! pic_sym_p(pic_list_ref(pic, spec, 1))) {
+        pic_error(pic, "syntax error");
+      }
+      sym = pic_sym(pic_list_ref(pic, spec, 1));
+      if (! pic_sym_p(pic_list_ref(pic, spec, 2))) {
+        pic_error(pic, "syntax error");
+      }
+      as = pic_sym(pic_list_ref(pic, spec, 2));
+    }
+    else {
       pic_error(pic, "syntax error");
     }
     /* TODO: warn if symbol is shadowed by local variable */
-    pic_export(pic, pic_sym(spec));
+    pic_export_as(pic, sym, as);
   }
 
   return pic_none_value();