1 files changed, 25 insertions, 1 deletions

diff --git a/sloth.c b/sloth.c
index 7c861c8..500c327 100644
--- a/sloth.c
+++ b/sloth.c
@@ -33,6 +33,11 @@ SlothError sloth_init(Sloth *ctx)
 		sloth_deinit(ctx);
 		return err;
 	}
+	err = sloth_dict_append(ctx, SLOTH_DICT_C("neg", sloth_neg));
+	if (err != NULL) {
+		sloth_deinit(ctx);
+		return err;
+	}
 	err = sloth_dict_append(ctx, SLOTH_DICT_C(":", sloth_compile_begin));
 	if (err != NULL) {
 		sloth_deinit(ctx);
@@ -43,6 +48,11 @@ SlothError sloth_init(Sloth *ctx)
 		sloth_deinit(ctx);
 		return err;
 	}
+	err = sloth_dict_append(ctx, SLOTH_DICT_C(".t", sloth_inspect_stack));
+	if (err != NULL) {
+		sloth_deinit(ctx);
+		return err;
+	}
 	return NULL;
 }
 
@@ -283,6 +293,19 @@ SlothError sloth_compare(Sloth *ctx)
 	return NULL;
 }
 
+SlothError sloth_neg(Sloth *ctx)
+{
+	SlothError err;
+	SlothByte a;
+	err = sloth_pop(ctx, &a);
+	if (err != NULL)
+		return err;
+	err = sloth_push(ctx, -a);
+	if (err != NULL)
+		return err;
+	return NULL;
+}
+
 SlothError sloth_compile_begin(Sloth *ctx)
 {
 	if (ctx->compile)
@@ -311,9 +334,10 @@ SlothError sloth_compile_end(Sloth *ctx)
 	return NULL;
 }
 
-void sloth_inspect_stack(const Sloth *ctx)
+SlothError sloth_inspect_stack(Sloth *ctx)
 {
 	printf("<%lu> ", ctx->stack_size);
 	for (size_t i = 0; i < ctx->stack_size; i++)
 		printf("%d ", ctx->stack[i]);
+	return NULL;
 }