From 818430bb81ac967f8ac69b7ec4828da5bc2c7b5b Mon Sep 17 00:00:00 2001
From: Yuichi Nishiwaki <yuichi.nishiwaki@gmail.com>
Date: Sat, 7 Dec 2013 09:42:34 -0800
Subject: [PATCH] implement import/export syntax

---
 include/picrin.h |  1 +
 src/lib.c        | 12 ++++++++++++
 src/macro.c      | 34 +++++++++++++++++++++++++++++-----
 3 files changed, 42 insertions(+), 5 deletions(-)

diff --git a/include/picrin.h b/include/picrin.h
index d4262b45..fec7bd9d 100644
--- a/include/picrin.h
+++ b/include/picrin.h
@@ -124,6 +124,7 @@ pic_value pic_macroexpand(pic_state *, pic_value);
 
 void pic_make_library(pic_state *, const char *);
 void pic_in_library(pic_state *, const char *);
+struct pic_lib *pic_find_library(pic_state *, pic_value);
 
 void pic_abort(pic_state *, const char *);
 void pic_raise(pic_state *, pic_value);
diff --git a/src/lib.c b/src/lib.c
index 2f7a5dd2..ba7ac212 100644
--- a/src/lib.c
+++ b/src/lib.c
@@ -42,3 +42,15 @@ pic_in_library(pic_state *pic, const char *name)
 
   pic->lib = pic_lib_ptr(pic_cdr(pic, v));
 }
+
+struct pic_lib *
+pic_find_library(pic_state *pic, pic_value spec)
+{
+  pic_value v;
+
+  v = pic_assoc(pic, spec, pic->lib_tbl);
+  if (pic_false_p(v)) {
+    return NULL;
+  }
+  return pic_lib_ptr(pic_cdr(pic, v));
+}
diff --git a/src/macro.c b/src/macro.c
index 7dddcf60..807355b2 100644
--- a/src/macro.c
+++ b/src/macro.c
@@ -238,17 +238,41 @@ macroexpand(pic_state *pic, pic_value expr, struct pic_senv *senv)
         pic_value program;
         struct pic_senv *senv;
 
-        /* FIXME: replace it with null-env once import is implemented */
-        senv = pic_core_syntactic_env(pic);
+        senv = pic_minimal_syntactic_env(pic);
 
+        if (pic_length(pic, expr) < 2) {
+          pic_error(pic, "syntax error");
+        }
         program = macroexpand_list(pic, pic_cddr(pic, expr), senv);
 
         return pic_cons(pic, pic_symbol_value(pic->sBEGIN), program);
       }
-      case PIC_STX_IMPORT:
+      case PIC_STX_IMPORT: {
+        struct pic_lib *lib;
+        struct xh_iterator it;
+
+        lib = pic_find_library(pic, pic_cadr(pic, expr));
+        if (! lib) {
+          pic_error(pic, "library not found");
+        }
+        it = xh_begin(lib->exports);
+        while (! xh_isend(&it)) {
+          xh_put(pic->lib->senv->tbl, it.e->key, it.e->val);
+          xh_next(lib->exports, &it);
+        }
+        return pic_false_value();
+      }
       case PIC_STX_EXPORT: {
-        puts("FIXME: import/export");
-        abort();
+        pic_sym orig, ren;
+        pic_value v;
+
+        orig = ren = pic_sym(pic_car(pic, expr));
+        v = macroexpand(pic, pic_car(pic, expr), senv);
+        if (pic_symbol_p(v)) {
+          ren = pic_sym(v);
+        }
+        xh_put(pic->lib->exports, pic_symbol_name(pic, orig), (int)ren);
+        return pic_false_value();
       }
       case PIC_STX_DEFSYNTAX: {
 	pic_value var, val;