The subject disclosure pertains to systems and methods for dynamic parsing. A dynamic parser can perform syntactic analysis or parsing of input data consisting of a set of tokens based upon a provided grammar including conditional tokens. While the parser grammar can be fixed, the dynamic parser can utilize an independent transform function at parse time to translate or replace particular tokens, effectively performing dynamic parsing. The transform function can be utilized in conjunction with conditional tokens to selectively activate and deactivate particular grammar rules. Additionally, systems and methods for automatically generating a dynamic parser from a grammar description are described herein.