From e1efd41abe6177b3daf1c02053767a70b71f1b2c Mon Sep 17 00:00:00 2001
From: "Jan (janneke) Nieuwenhuizen" <janneke@gnu.org>
Date: Tue, 18 Aug 2020 09:36:19 +0200
Subject: [PATCH] core: builtins: MES_MINI.

* include/mes/mes.h (g_mini): New global.
* src/mes.c (init): Initialize it with environment variable MES_MINI.
* src/builtins.c (mes_builtins): Register a minimal set of builtins
when g_mini.
---
 include/mes/mes.h |  1 +
 src/builtins.c    | 22 +++++++++++++++++++---
 src/mes.c         |  1 +
 3 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/include/mes/mes.h b/include/mes/mes.h
index 11df1a35..dee7d31f 100644
--- a/include/mes/mes.h
+++ b/include/mes/mes.h
@@ -59,6 +59,7 @@ char *g_buf;
 SCM g_continuations;
 SCM g_symbols;
 SCM g_symbol_max;
+int g_mini;
 
 /* a/env */
 SCM R0;
diff --git a/src/builtins.c b/src/builtins.c
index dae42312..4c0747ad 100644
--- a/src/builtins.c
+++ b/src/builtins.c
@@ -109,11 +109,27 @@ init_builtin (SCM builtin_type, char const *name, int arity, FUNCTION function,
 SCM
 mes_builtins (SCM a)            /*:((internal)) */
 {
-  // TODO minimal: cons, car, cdr, list, null_p, eq_p minus, plus
-  // display_, display_error_, getenv
-
   SCM builtin_type = make_builtin_type ();
 
+  if (g_mini != 0)
+    {
+      a = init_builtin (builtin_type, "cons", 2, &cons, a);
+      a = init_builtin (builtin_type, "car", 1, &car, a);
+      a = init_builtin (builtin_type, "list", -1, &list, a);
+      a = init_builtin (builtin_type, "eq?", 2, &eq_p, a);
+      a = init_builtin (builtin_type, "-", -1, &minus, a);
+      a = init_builtin (builtin_type, "+", -1, &plus, a);
+      a = init_builtin (builtin_type, "core:display", 1, &display_, a);
+      a = init_builtin (builtin_type, "core:write", 1, &write_, a);
+      a = init_builtin (builtin_type, "core:display-error", 1, &display_error_, a);
+      a = init_builtin (builtin_type, "getenv", 1, &getenv_, a);
+      a = init_builtin (builtin_type, "gc", 0, &gc, a);
+      a = init_builtin (builtin_type, ">", -1, &greater_p, a);
+      a = init_builtin (builtin_type, "<", -1, &less_p, a);
+      a = init_builtin (builtin_type, "make-vector", -1, &make_vector, a);
+      return a;
+    }
+
   /* src/builtins.c */
   a = init_builtin (builtin_type, "make-builtin", 4, &make_builtin, a);
   a = init_builtin (builtin_type, "builtin-name", 1, &builtin_name, a);
diff --git a/src/mes.c b/src/mes.c
index 90831590..927b5eb1 100644
--- a/src/mes.c
+++ b/src/mes.c
@@ -177,6 +177,7 @@ init (char **envp)
   char *p;
   if (p = getenv ("MES_DEBUG"))
     g_debug = atoi (p);
+  g_mini = getenv ("MES_MINI");
   open_boot ();
   gc_init ();
 }