In this paper we present Grammatic -- a tool for textual syntax definition. Grammatic serves as a front-end for parser generators (and other tools) and brings modularity and reuse to their development artifacts. It adapts techniques for separation of concerns from Apsect-Oriented Programming to grammars and uses templates for grammar reuse. We illustrate usage of Grammatic by describing a case study: bringing separation of concerns to ANTLR parser generator, which is achieved without a common time- and memory-consuming technique of building an AST to separate semantic actions from a grammar definition.