1 files changed, 9 insertions, 1 deletions
diff --git a/src/smp/__init__.py b/src/smp/__init__.py
index 5358c29..f7cb937 100644
--- a/src/smp/__init__.py
+++ b/src/smp/__init__.py
@@ -35,13 +35,21 @@ def main():
         "-D", nargs="+", metavar="key=value", default=[], action="extend"
     )
     parser.add_argument(
+        "-P",
+        "--prefix-builtins",
+        default=False,
+        action="store_true",
+        help="Prefix builtins with smp_",
+    )
+    parser.add_argument(
         "file", nargs="?", default=None, help='Input file or "-" for stdin'
     )
     args = parser.parse_args()
     args.D = parse_keyval_args(args.D)
 
     macro_processor_state = smp.macro_processor.MacroProcessorState()
-    macro_processor = macro_processor_state.macro_processor()
+    prefix = "smp_" if args.prefix_builtins else ""
+    macro_processor = macro_processor_state.macro_processor(prefix=prefix)
 
     for key, value in args.D.items():
         macro_processor.define_macro(key, value)