Add if primitive procedure

2 files changed, 23 insertions, 1 deletions

diff --git a/src/bootstrap/main.c b/src/bootstrap/main.c
index a8ba7bc..8ec1231 100755
--- a/src/bootstrap/main.c
+++ b/src/bootstrap/main.c
@@ -40,6 +40,7 @@ init(void) {
     environment[env_n++] = (EnvSymbol){MAKE_SYM("not"), make_procedure(proc_not)};
     environment[env_n++] = (EnvSymbol){MAKE_SYM("and"), make_procedure(proc_and)};
     environment[env_n++] = (EnvSymbol){MAKE_SYM("or"), make_procedure(proc_or)};
+    environment[env_n++] = (EnvSymbol){MAKE_SYM("if"), make_procedure(proc_if)};
     environment[env_n++] = (EnvSymbol){MAKE_SYM("display"), make_procedure(proc_display)};
     environment[env_n++] = (EnvSymbol){MAKE_SYM("print"), make_procedure(proc_print)};
 }
diff --git a/src/bootstrap/primitives.c b/src/bootstrap/primitives.c
index 97058f9..61ce360 100644
--- a/src/bootstrap/primitives.c
+++ b/src/bootstrap/primitives.c
@@ -309,5 +309,26 @@ proc_or(Object *args) {
     return obj_false;
 }
 
-// TODO: if/cond
+Object *
+proc_if(Object *args) {
+    if (args->type != OBJ_TYPE_PAIR || args->cdr->type != OBJ_TYPE_PAIR) {
+        fprintf(stderr, "error: wrong number of arguments.\n");
+        return NULL;
+    }
+
+    Object *condition = eval(args->car);
+    if (condition == obj_true) {
+        Object *ret = eval(args->cdr->car);
+        return ret;
+    }
+    if (args->cdr->cdr != obj_nil) {
+        Object *ret = eval(args->cdr->cdr->car);
+        return ret;
+    }
+
+    return obj_nil;
+}
+
+// TODO: cond
+// TODO: equality greater than smaller than...
 // TODO: fixnum left/right shift, mask, invert