From c10f40acd4808137bae6d74d77d09e5e94ca98ab Mon Sep 17 00:00:00 2001
From: Yuichi Nishiwaki <yuichi.nishiwaki@gmail.com>
Date: Thu, 27 Mar 2014 16:19:55 +0900
Subject: [PATCH] change pic_find_rename API

---
 include/picrin/macro.h |  2 +-
 src/codegen.c          |  2 +-
 src/macro.c            | 24 +++++++++++++-----------
 src/vm.c               |  2 +-
 4 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/include/picrin/macro.h b/include/picrin/macro.h
index d6b0814e..14097046 100644
--- a/include/picrin/macro.h
+++ b/include/picrin/macro.h
@@ -42,7 +42,7 @@ struct pic_senv *pic_minimal_syntactic_env(pic_state *);
 struct pic_senv *pic_core_syntactic_env(pic_state *);
 
 pic_sym pic_add_rename(pic_state *, struct pic_senv *, pic_sym);
-pic_sym pic_find_rename(pic_state *, struct pic_senv *, pic_sym); /* may return 0! */
+bool pic_find_rename(pic_state *, struct pic_senv *, pic_sym, pic_sym * /* = NULL */);
 void pic_put_rename(pic_state *, struct pic_senv *, pic_sym, pic_sym);
 
 #if defined(__cplusplus)
diff --git a/src/codegen.c b/src/codegen.c
index 9c662329..aabca6b6 100644
--- a/src/codegen.c
+++ b/src/codegen.c
@@ -51,7 +51,7 @@ static void pop_scope(analyze_state *);
 #define register_renamed_symbol(pic, state, slot, lib, id) do {         \
     pic_sym sym, gsym;                                                  \
     sym = pic_intern_cstr(pic, id);                                     \
-    if ((gsym = pic_find_rename(pic, lib->senv, sym)) == 0) {           \
+    if (! pic_find_rename(pic, lib->senv, sym, &gsym)) {                \
       pic_error(pic, "internal error! native VM procedure not found");  \
     }                                                                   \
     state->slot = gsym;                                                 \
diff --git a/src/macro.c b/src/macro.c
index 7703d5ee..e11fd3ed 100644
--- a/src/macro.c
+++ b/src/macro.c
@@ -28,17 +28,20 @@ pic_put_rename(pic_state *pic, struct pic_senv *senv, pic_sym sym, pic_sym renam
   xh_put(&senv->renames, sym, &rename);
 }
 
-pic_sym
-pic_find_rename(pic_state *pic, struct pic_senv *senv, pic_sym sym)
+bool
+pic_find_rename(pic_state *pic, struct pic_senv *senv, pic_sym sym, pic_sym *rename)
 {
   xh_entry *e;
 
   UNUSED(pic);
 
   if ((e = xh_get(&senv->renames, sym)) == NULL) {
-    return 0;
+    return false;
   }
-  return xh_val(e, pic_sym);
+  if (rename != NULL) {
+    *rename = xh_val(e, pic_sym);
+  }
+  return true;
 }
 
 static pic_value macroexpand(pic_state *, pic_value, struct pic_senv *);
@@ -160,8 +163,7 @@ pic_export(pic_state *pic, pic_sym sym)
 {
   pic_sym rename;
 
-  rename = pic_find_rename(pic, pic->lib->senv, sym);
-  if (rename == 0) {
+  if (! pic_find_rename(pic, pic->lib->senv, sym, &rename)) {
     pic_errorf(pic, "export: symbol not defined %s", pic_symbol_name(pic, sym));
   }
 
@@ -199,7 +201,7 @@ symbol_rename(pic_state *pic, pic_sym sym, struct pic_senv *senv)
     return sym;
   }
   while (true) {
-    if ((rename = pic_find_rename(pic, senv, sym)) != 0) {
+    if (pic_find_rename(pic, senv, sym, &rename)) {
       return rename;
     }
     if (! senv->up)
@@ -318,7 +320,7 @@ macroexpand_node(pic_state *pic, pic_value expr, struct pic_senv *senv)
           pic_error(pic, "binding to non-symbol object");
         }
         sym = pic_sym(var);
-        if ((rename = pic_find_rename(pic, senv, sym)) == 0) {
+        if (! pic_find_rename(pic, senv, sym, &rename)) {
           rename = pic_add_rename(pic, senv, sym);
         }
 
@@ -367,7 +369,7 @@ macroexpand_node(pic_state *pic, pic_value expr, struct pic_senv *senv)
 	  pic_error(pic, "syntax error");
 	}
         sym = pic_sym(var);
-        if ((rename = pic_find_rename(pic, senv, sym)) == 0) {
+        if (! pic_find_rename(pic, senv, sym, &rename)) {
           rename = pic_add_rename(pic, senv, sym);
         }
 
@@ -418,7 +420,7 @@ macroexpand_node(pic_state *pic, pic_value expr, struct pic_senv *senv)
 	    pic_error(pic, "binding to non-symbol object");
 	  }
           sym = pic_sym(a);
-          if (pic_find_rename(pic, senv, sym) == 0) {
+          if (! pic_find_rename(pic, senv, sym, NULL)) {
             pic_add_rename(pic, senv, sym);
           }
 
@@ -436,7 +438,7 @@ macroexpand_node(pic_state *pic, pic_value expr, struct pic_senv *senv)
 	  pic_error(pic, "binding to non-symbol object");
 	}
         sym = pic_sym(formals);
-        if (pic_find_rename(pic, senv, sym) == 0) {
+        if (! pic_find_rename(pic, senv, sym, NULL)) {
           pic_add_rename(pic, senv, sym);
         }
 
diff --git a/src/vm.c b/src/vm.c
index b94c8139..be3fe654 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -336,7 +336,7 @@ global_ref(pic_state *pic, const char *name)
   pic_sym sym, rename;
 
   sym = pic_intern_cstr(pic, name);
-  if ((rename = pic_find_rename(pic, pic->lib->senv, sym)) == 0) {
+  if (! pic_find_rename(pic, pic->lib->senv, sym, &rename)) {
     return SIZE_MAX;
   }
   if (! (e = xh_get(&pic->global_tbl, rename))) {