From d0abe2d193b3d1bfb11a1bee6a915e664a9cb25a Mon Sep 17 00:00:00 2001
From: Yuichi Nishiwaki <yuichi.nishiwaki@gmail.com>
Date: Wed, 10 Sep 2014 01:41:10 +0900
Subject: [PATCH] add pic->feature

---
 gc.c             | 2 ++
 include/picrin.h | 5 ++++-
 init.c           | 9 +++++++++
 state.c          | 4 ++++
 4 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/gc.c b/gc.c
index 9520e40a..f52d2fd7 100644
--- a/gc.c
+++ b/gc.c
@@ -618,6 +618,8 @@ gc_mark_phase(pic_state *pic)
     }
   }
 
+  gc_mark(pic, pic->features);
+
   /* readers */
   gc_mark_trie(pic, pic->reader->trie);
 
diff --git a/include/picrin.h b/include/picrin.h
index fff10cbb..ac03feb6 100644
--- a/include/picrin.h
+++ b/include/picrin.h
@@ -87,6 +87,8 @@ typedef struct {
   struct pic_lib *PICRIN_BASE;
   struct pic_lib *PICRIN_USER;
 
+  pic_value features;
+
   xhash syms;                   /* name to symbol */
   xhash sym_names;              /* symbol to name */
   int sym_cnt;
@@ -137,10 +139,11 @@ void pic_gc_arena_restore(pic_state *, size_t);
 pic_state *pic_open(int argc, char *argv[], char **envp);
 void pic_close(pic_state *);
 
+void pic_add_feature(pic_state *, const char *);
+
 void pic_define(pic_state *, const char *, pic_value); /* automatic export */
 pic_value pic_ref(pic_state *, struct pic_lib *, const char *);
 void pic_set(pic_state *, struct pic_lib *, const char *, pic_value);
-
 pic_value pic_funcall(pic_state *pic, const char *name, pic_list args);
 
 struct pic_proc *pic_get_proc(pic_state *);
diff --git a/init.c b/init.c
index a5e70d71..77e16524 100644
--- a/init.c
+++ b/init.c
@@ -8,6 +8,12 @@
 #include "picrin/macro.h"
 #include "picrin/error.h"
 
+void
+pic_add_feature(pic_state *pic, const char *feature)
+{
+  pic_push(pic, pic_sym_value(pic_intern_cstr(pic, feature)), pic->features);
+}
+
 void pic_init_bool(pic_state *);
 void pic_init_pair(pic_state *);
 void pic_init_port(pic_state *);
@@ -42,6 +48,9 @@ pic_init_core(pic_state *pic)
 {
   size_t ai = pic_gc_arena_preserve(pic);
 
+  pic_add_feature(pic, "picrin");
+  pic_add_feature(pic, "ieee-float");
+
   pic_deflibrary (pic, "(picrin base)") {
     pic_define_syntactic_keyword(pic, pic->lib->env, pic->sDEFINE, pic->rDEFINE);
     pic_define_syntactic_keyword(pic, pic->lib->env, pic->sSETBANG, pic->rSETBANG);
diff --git a/state.c b/state.c
index 0b2b5123..07d85892 100644
--- a/state.c
+++ b/state.c
@@ -57,6 +57,9 @@ pic_open(int argc, char *argv[], char **envp)
   /* macros */
   xh_init_int(&pic->macros, sizeof(struct pic_macro *));
 
+  /* features */
+  pic->features = pic_nil_value();
+
   /* libraries */
   pic->libs = pic_nil_value();
   pic->lib = NULL;
@@ -184,6 +187,7 @@ pic_close(pic_state *pic)
   pic->arena_idx = 0;
   pic->err = NULL;
   xh_clear(&pic->macros);
+  pic->features = pic_nil_value();
   pic->libs = pic_nil_value();
 
   /* free all heap objects */