1. A system for parsing complex data, the system comprising: a memory device configured to store a set of instructions; and at least one processor configured to execute the set of instructions to perform the following operations: input one or more strings into a parsing pipeline within a parser, and execute, for each inputted string into the parsing pipeline, the following operations: generate a second string, by a first handler, based in part on a current input string to the parsing pipeline, if the current input string to the parsing pipeline matches an expression specified for the first handler in a parser definition; and input the second string, regeneratively, by the first handler, to the parsing pipeline, if the current input string to the parsing pipeline matches an expression specified for the first handler in the parser definition.