rearrange builtins

builtins/assert.go

@@ -0,0 +1,31 @@
+package builtins
+
+import "monkey/object"
+
+import (
+	"fmt"
+	"os"
+)
+
+// Assert ...
+func Assert(args ...object.Object) object.Object {
+	if len(args) != 2 {
+		return newError("wrong number of arguments. got=%d, want=2",
+			len(args))
+	}
+	if args[0].Type() != object.BOOLEAN_OBJ {
+		return newError("argument #1 to `assert` must be BOOLEAN, got %s",
+			args[0].Type())
+	}
+	if args[1].Type() != object.STRING_OBJ {
+		return newError("argument #2 to `assert` must be STRING, got %s",
+			args[0].Type())
+	}
+
+	if !args[0].(*object.Boolean).Value {
+		fmt.Printf("Assertion Error: %s", args[1].(*object.String).Value)
+		os.Exit(1)
+	}
+
+	return nil
+}