SLR Parser Online

This tool provides an online SLR parsing workflow for learners and professionals. It accepts a grammar in standard notation, a designated start symbol, and an input sequence of terminals. It builds the canonical collection of LR(0) items and constructs the ACTION and GOTO tables using FOLLOW sets to determine reductions. The system reports conflicts (shift/reduce, reduce/reduce), explains the responsible productions, and presents a stepwise parse trace to help users diagnose ambiguities. Example grammars include arithmetic expressions and token streams such as id, +, and *. The tool is designed for education and debugging, not for code generation, and it emphasizes deterministic parsing behavior where possible. It also supports visualization of item sets and derivations to aid understanding, with optional FIRST and FOLLOW visualization for deeper learning. By separating the required structural computations from optional diagnostics, users can validate grammars quickly or perform in-depth analysis as needed. This yields a practical, self-contained environment for practicing SLR parsing concepts, validating grammar reachability, and observing how grammar changes affect parsing decisions.