diff --git a/include/picrin.h b/include/picrin.h
index 11287003..ffb8d341 100644
--- a/include/picrin.h
+++ b/include/picrin.h
@@ -127,6 +127,15 @@ void pic_in_library(pic_state *, pic_value);
 struct pic_lib *pic_make_library(pic_state *, pic_value);
 struct pic_lib *pic_find_library(pic_state *, pic_value);
 
+#define DEFLIBRARY(pic,name)                                    \
+  {                                                             \
+    struct pic_lib *lib__ = pic->lib;                           \
+    pic_make_library(pic, pic_parse(pic, name));                \
+    pic_in_library(pic, pic_parse(pic, name));
+#define ENDLIBRARY(pic)                                         \
+    pic->lib = lib__;                                           \
+  }
+
 void pic_export(pic_state *, pic_sym);
 void pic_export_as(pic_state *, pic_sym, pic_sym);
 
diff --git a/src/file.c b/src/file.c
index 7c15d28d..307a6688 100644
--- a/src/file.c
+++ b/src/file.c
@@ -105,10 +105,14 @@ pic_file_delete(pic_state *pic)
 void
 pic_init_file(pic_state *pic)
 {
-  pic_defun(pic, "open-input-file", pic_file_open_input_file);
-  pic_defun(pic, "open-input-binary-file", pic_file_open_input_binary_file);
-  pic_defun(pic, "open-output-file", pic_file_open_output_file);
-  pic_defun(pic, "open-output-binary-file", pic_file_open_output_binary_file);
-  pic_defun(pic, "file-exists?", pic_file_exists_p);
-  pic_defun(pic, "delete-file", pic_file_delete);
+  DEFLIBRARY(pic, "(scheme file)")
+  {
+    pic_defun(pic, "open-input-file", pic_file_open_input_file);
+    pic_defun(pic, "open-input-binary-file", pic_file_open_input_binary_file);
+    pic_defun(pic, "open-output-file", pic_file_open_output_file);
+    pic_defun(pic, "open-output-binary-file", pic_file_open_output_binary_file);
+    pic_defun(pic, "file-exists?", pic_file_exists_p);
+    pic_defun(pic, "delete-file", pic_file_delete);
+  }
+  ENDLIBRARY(pic)
 }
diff --git a/src/port.c b/src/port.c
index fb5abd3c..312a57c1 100644
--- a/src/port.c
+++ b/src/port.c
@@ -331,11 +331,16 @@ pic_init_port(pic_state *pic)
   pic_defun(pic, "port?", pic_port_port_p);
   pic_defun(pic, "input-port-open?", pic_port_input_port_open_p);
   pic_defun(pic, "output-port-open?", pic_port_output_port_open_p);
-  pic_defun(pic, "write", pic_port_write);
-  pic_defun(pic, "newline", pic_port_newline);
   pic_defun(pic, "eof-object?", pic_port_eof_object_p);
   pic_defun(pic, "eof-object", pic_port_eof_object);
   pic_defun(pic, "close-port", pic_port_close_port);
   pic_defun(pic, "close-input-port", pic_port_close_port);
   pic_defun(pic, "close-output-port", pic_port_close_port);
+
+  DEFLIBRARY(pic, "(scheme write)")
+  {
+    pic_defun(pic, "write", pic_port_write);
+    pic_defun(pic, "newline", pic_port_newline);
+  }
+  ENDLIBRARY(pic)
 }
diff --git a/src/system.c b/src/system.c
index 097389e0..8d7f2e00 100644
--- a/src/system.c
+++ b/src/system.c
@@ -115,9 +115,13 @@ pic_system_getenvs(pic_state *pic)
 void
 pic_init_system(pic_state *pic)
 {
-  pic_defun(pic, "command-line", pic_system_cmdline);
-  pic_defun(pic, "exit", pic_system_exit);
-  pic_defun(pic, "emergency-exit", pic_system_emergency_exit);
-  pic_defun(pic, "get-environment-variable", pic_system_getenv);
-  pic_defun(pic, "get-environment-variables", pic_system_getenvs);
+  DEFLIBRARY(pic, "(scheme process-context)")
+  {
+    pic_defun(pic, "command-line", pic_system_cmdline);
+    pic_defun(pic, "exit", pic_system_exit);
+    pic_defun(pic, "emergency-exit", pic_system_emergency_exit);
+    pic_defun(pic, "get-environment-variable", pic_system_getenv);
+    pic_defun(pic, "get-environment-variables", pic_system_getenvs);
+  }
+  ENDLIBRARY(pic)
 }
diff --git a/src/time.c b/src/time.c
index e6076b24..9bdd8aa0 100644
--- a/src/time.c
+++ b/src/time.c
@@ -37,7 +37,11 @@ pic_jiffies_per_second(pic_state *pic)
 void
 pic_init_time(pic_state *pic)
 {
-  pic_defun(pic, "current-second", pic_current_second);
-  pic_defun(pic, "current-jiffy", pic_current_jiffy);
-  pic_defun(pic, "jiffies-per-second", pic_jiffies_per_second);
+  DEFLIBRARY(pic, "(scheme time)")
+  {
+    pic_defun(pic, "current-second", pic_current_second);
+    pic_defun(pic, "current-jiffy", pic_current_jiffy);
+    pic_defun(pic, "jiffies-per-second", pic_jiffies_per_second);
+  }
+  ENDLIBRARY(pic)
 }