Grammar Definition
- nearley:
nearleyuses a simple and expressive syntax for defining grammars, supporting both ambiguous and unambiguous grammars. It allows for the inclusion of JavaScript code for actions, providing flexibility in how parsed data is handled. - langium:
langiumsupports grammar definition using a DSL (Domain-Specific Language) syntax, which is designed to be intuitive for language designers. It provides rich support for defining syntax, semantics, and tooling features like auto-completion and validation. - antlr4:
antlr4uses a context-free grammar (CFG) format, allowing for complex and hierarchical grammar definitions. It supports features like actions, semantic predicates, and error handling directly within the grammar files. - pegjs:
pegjsuses Parsing Expression Grammar (PEG) notation to define grammars. It is simple and expressive, allowing for clear and concise grammar definitions. PEGs are particularly good at handling ambiguities and provide a deterministic parsing approach. - jison:
jisonallows grammar definition using a BNF-like syntax, which is straightforward and easy to understand. It supports embedding JavaScript code for actions, making it flexible for custom parsing logic.
Parser Generation
- nearley:
nearleygenerates parsers from the defined grammars, producing efficient JavaScript code. It supports both top-down and bottom-up parsing strategies, allowing for flexibility in how the parsing is performed. - langium:
langiumgenerates parsers and accompanying tooling (like editors with syntax highlighting, validation, etc.) from the defined DSL grammar. It focuses on providing a complete ecosystem for language development. - antlr4:
antlr4generates parsers in multiple target languages (JavaScript, Java, C#, etc.) from a single grammar file. It provides a rich set of APIs for traversing and manipulating the parse tree or abstract syntax tree (AST). - pegjs:
pegjsgenerates fast and efficient parsers from PEG grammars. The generated parsers are JavaScript functions that can be easily integrated into any application, providing a simple API for parsing input strings. - jison:
jisongenerates JavaScript parsers from the defined grammars, producing efficient and lightweight parser code that can be easily integrated into web applications or Node.js projects.
Error Handling
- nearley:
nearleyprovides basic error handling capabilities, including the ability to report syntax errors and integrate custom error handling logic within the grammar. However, it is relatively simple compared to other libraries. - langium:
langiumincludes built-in error handling for syntax errors, with support for customizable error messages and integration with IDEs for real-time error feedback. It is designed to provide a good developer experience when working with DSLs. - antlr4:
antlr4provides advanced error handling capabilities, including customizable error messages, recovery strategies, and the ability to define error nodes in the grammar. This makes it suitable for building robust parsers that can handle malformed input gracefully. - pegjs:
pegjsoffers good error handling features, including detailed error messages and the ability to define custom error handling logic within the grammar. It provides clear feedback on parsing errors, which is helpful for debugging. - jison:
jisonsupports error handling through the definition of error rules in the grammar. Developers can specify custom error messages and recovery strategies, making it flexible for handling parsing errors.
Performance
- nearley:
nearleyis known for its performance, especially with unambiguous grammars. It is lightweight and fast, making it suitable for applications that require quick parsing with minimal overhead. - langium:
langiumfocuses more on providing rich tooling and features for DSL development rather than raw parsing performance. While it is efficient for typical use cases, it may not be optimized for parsing very large inputs. - antlr4:
antlr4is optimized for performance, especially when parsing large and complex inputs. It uses efficient algorithms for lexical and syntactic analysis, and the generated parsers are designed to be fast and memory-efficient. - pegjs:
pegjsproduces fast parsers with a small memory footprint, making it ideal for performance-sensitive applications. The use of PEGs allows for efficient parsing, and the generated parsers are highly optimized. - jison:
jisongenerates parsers that are generally efficient, but performance can vary depending on the complexity of the grammar and the amount of embedded JavaScript code. It is suitable for most applications but may not be the best choice for extremely performance-critical scenarios.
Ease of Use: Code Examples
- nearley:
nearleyExample// Define a simple grammar in Nearley syntax @{% const { Parser } = require('nearley'); const grammar = require('./grammar.ne'); const parser = new Parser(grammar); %} // Define the grammar in a separate file (grammar.ne) @{% // This is a simple grammar for parsing greetings # A greeting can be 'hello' followed by a name main -> 'hello' name name -> [a-zA-Z]+ // Match one or more letters // Generate the parser using Nearley // nearleyc grammar.ne -o grammar.js %} // Use the generated parser in JavaScript const input = 'hello Alice'; parser.feed(input); const result = parser.results; console.log(result); - langium:
langiumExample// Define a simple DSL grammar in Langium syntax grammar Simple // Define a rule for a greeting Greeting: 'hello' Name; Name: [a-zA-Z]+; // Generate the parser and tooling using Langium // langium generate // Use the generated parser in JavaScript const { parse } = require('./generated/parser'); const { createLangiumServices } = require('./generated/services'); const services = createLangiumServices(); const parser = services.parser; const input = 'hello John'; const result = parser.parse(input); console.log(result); - antlr4:
antlr4Example// Define a simple grammar in ANTLR syntax grammar Hello; // Parser rules r : 'hello' ID; ID : [a-zA-Z]+; // Lexer rules WS : [ \t\r\n]+ -> skip;// Generate parser using ANTLR tool // antlr4 Hello.g4 -Dlanguage=JavaScript
// Use the generated parser in JavaScript const antlr4 = require('antlr4'); const HelloLexer = require('./HelloLexer'); const HelloParser = require('./HelloParser');
const input = 'hello world'; const chars = new antlr4.InputStream(input); const lexer = new HelloLexer.HelloLexer(chars); const tokens = new antlr4.CommonTokenStream(lexer); const parser = new HelloParser.HelloParser(tokens); const tree = parser.r(); // Parse the input console.log(tree.toStringTree(parser.ruleNames)); // Print the parse tree
- pegjs:
pegjsExample// Define a simple grammar in PEG.js syntax start = 'hello' ' ' name:name / 'goodbye' ' ' name:name / 'invalid' name = [a-zA-Z]+ // Match one or more letters // Generate the parser using PEG.js // pegjs grammar.pegjs // Use the generated parser in JavaScript const peg = require('./grammar'); const result = peg.parse('hello John'); console.log(result); - jison:
jisonExample// Define a simple grammar in Jison syntax %lex %% \s+ ; // Ignore whitespace hello return 'HELLO'; world return 'WORLD'; . return 'INVALID'; %% %start start %% start : HELLO WORLD { console.log('Parsed: hello world'); } | HELLO INVALID { console.log('Parsed: hello with invalid'); } | INVALID WORLD { console.log('Parsed: invalid with world'); } ; // Generate the parser using Jison // jison hello.jison // Use the generated parser in JavaScript const parser = require('./hello'); parser.parse('hello world'); // Parsed: hello world parser.parse('hello invalid'); // Parsed: hello with invalid parser.parse('invalid world'); // Parsed: invalid with world
