antlr4

来源： https://stackoverflow.com/questions/30479367/antlr4-recover-from-error-and-continue-parsing-until-eof

来源： https://stackoverflow.com/questions/49116223/convert-antlr-parse-tree-to-json

来源： https://stackoverflow.com/questions/49116223/convert-antlr-parse-tree-to-json

问题 I have some doubts regarding the performance of Antlr4. I am currently using Python with Antlr4. It is terribly slow compared to Java (Verified using Antlr4 IntelliJ plugin). Since I need to work with bigger codes for parsing, I am planning to switch to a language which will be the fastest with Antlr (Eg: Java, C or Python). Any suggestions? Any tips on optimizing the Antlr grammar for faster parsing (I am trying some online resources) If I continue with Python itself, what are the best ways

问题 I'm a newbie in AntLR. I'm using AntLR4 version. I wrote the following attribute grammar that recognizes a list of integers and print the sum of the list at the end. list.g4 grammar list; @header { import java.util.List; import java.util.ArrayList; } list : BEGL (elems[new ArrayList<Integer>()])? ENDL { int sum = 0; if($elems.text != null) for(Integer i : $elems.listOut) sum += i; System.out.println("List Sum: " + sum); } ; elems [List<Integer> listIn] returns [List<Integer> listOut] : a=elem

问题 I am trying to build an AST using the visitor pattern on ANTLR Java Grammar (Java Grammar) in C# (.Net Core 3.1). I have created IJavaParserVisitor , JavaParserbaseVisitor , JavaLexer , and JavaParser file for grammar and created parse tree for java source file. But when I am trying to create AST using JavaParserBaseVisitor.Visit() I am getting null as a result. AntlrFileStream stream = new AntlrFileStream(file); ITokenSource lexer = new JavaLexer(stream); ITokenStream tokens = new

问题 I am trying to build an AST using the visitor pattern on ANTLR Java Grammar (Java Grammar) in C# (.Net Core 3.1). I have created IJavaParserVisitor , JavaParserbaseVisitor , JavaLexer , and JavaParser file for grammar and created parse tree for java source file. But when I am trying to create AST using JavaParserBaseVisitor.Visit() I am getting null as a result. AntlrFileStream stream = new AntlrFileStream(file); ITokenSource lexer = new JavaLexer(stream); ITokenStream tokens = new

问题 I am trying to build an AST using the visitor pattern on ANTLR Java Grammar (Java Grammar) in C# (.Net Core 3.1). I have created IJavaParserVisitor , JavaParserbaseVisitor , JavaLexer , and JavaParser file for grammar and created parse tree for java source file. But when I am trying to create AST using JavaParserBaseVisitor.Visit() I am getting null as a result. AntlrFileStream stream = new AntlrFileStream(file); ITokenSource lexer = new JavaLexer(stream); ITokenStream tokens = new

问题 I've built a basic parser using the C++ runtime demo and it works fine. However I typically parse a lot of input strings, can the code be modified to reuse existing objects for repeated calls? If so, does anyone have an example of this? 回答1: Yes, reusing the objects is possible. A typcial sequence for a parse call looks like this then: input.load(newText); errors.clear(); lexer.reset(); lexer.setInputStream(&input); // Not just reset(), which only rewinds the current position. tokens

问题 I've built a basic parser using the C++ runtime demo and it works fine. However I typically parse a lot of input strings, can the code be modified to reuse existing objects for repeated calls? If so, does anyone have an example of this? 回答1: Yes, reusing the objects is possible. A typcial sequence for a parse call looks like this then: input.load(newText); errors.clear(); lexer.reset(); lexer.setInputStream(&input); // Not just reset(), which only rewinds the current position. tokens