Grammar to be agnostic to the target programming language. However, ANTLR separates this concern, allowing the Mentioned earlier, yacc requires language specific code to be embedded The Listener then allows us to make use of the the parsed input. The Parser uses the Lexer’s output and applies the Grammar’s rules.īuilding higher level constructs, such as expressions that can be used Input such as 1 + 2 * 3, the Lexer would return the following tokens: The Lexer takes arbitrary input and returns a stream of tokens. The generated files consist of three main components, the Lexer, Parser, Parser is built only Go and the ANTLR runtimeĭocumentation on how to install this on multiple platforms, but in brief, During development Java is needed, but once the Unlikeīison/Yacc which typically embeds target language code into theĪNTLR is a Java 1.7 application, that generates the Go code needed to A single grammarĬan be used to generate parsers in Java, Go, C, etc. Whereas LL(*) parsers encode the logic in its control flow, makingįinally ANTLR is agnostic to the target language. This is because LALR parsers are commonly table driven, The generated code for a LL(*) parser is more understandable than a Has a bearing on how the grammar is written, making some languages Simply LALR works bottom-up, and LL(*) works top-down. Whereas most other parser generators (e.g Bison and Yacc) areīetween LL(*) and LALR is out of scope for this article, but Syntax to define the grammar, instead of a bespoke configurationĪNTLR is an Adaptive LL(*) parser, ALL(*) for short, Makes writing and debugging grammars easy. Version of yacc, goyacc, which is written in Go and was part of the main Specific way, and generates code to parse that language. There are many parser generators that take a grammar expressed in an domain. This process can be complex, error prone, and hard to change. ThisĪrticle will explain some of the benefits of ANTLR, and walk us through Support was recentlyĪdded so that ANTLR 4 can be used to generate parsers in pure Go. Twitter even uses it to understand search queries. To parse Hadoop queries, Oracle and NetBeans uses it for their IDEs, and Trees (a data structure representing the input).ĪNTLR is used by a number of popular projects, e.g Hive and Pig use it Generated parser provides a callback interface to parse the input in anĮvent-driven manner, which can be used as-is, or used to build parse Java, C, C#, Javascript), that can process text or binary input. Layman’s terms, Antlr, creates parsers in a number of languages (Go, ANTLR (ANother Tool for Language Recognition),
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