About Tokeko
Tokeko builds an LR(1) or LALR parser from a grammar you write in the browser. Grammars can include terminals, non-terminals and tokens defined with regular expressions.
You can inspect the FIRST and FOLLOW sets, automaton states and transitions, and ACTION and GOTO tables. Enter an input string to follow the parse one step at a time and see the resulting tree.
The parser generator is dotlr, a Rust library also available on npm as @specy/dotlr.
Features
LR(1) and LALR parsers
Build either parser from the same grammar and compare the results.
FIRST and FOLLOW sets
Inspect the FIRST and FOLLOW sets for the symbols in your grammar.
Automaton
View parser states and transitions in a table or graph.
ACTION and GOTO tables
Inspect the actions and state transitions the parser uses for each input symbol.
Parsing steps and parse tree
Follow the state stack, symbol stack and remaining input at each step. Select a step for details, or inspect the final parse tree.
Editor and TypeScript runner
The grammar editor includes completion and error messages. Run TypeScript code in the app to work with the parser and its output.
Source code and links
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Learn
My computer science notes from university, written in Italian.