CODEWITHSUNDEEP
antlrantlr4grun
Альберт Александров
Альберт Александров

Reputation: 901

GRUN for Antlr4: How to use?

For grammar:

grammar qwe;

query
    : COLUMN OPERATOR value EOF
    ;

COLUMN
    : [a-z_]+
    ;

OPERATOR
    : ('='|'>'|'<')
    ;

SCALAR
    : [a-z_]+
    ;

value
    : SCALAR
    ;

WS : [ \t\r\n]+ -> skip ;

there are identical rules COLUMN and SCALAR. Here I was advised to use grun aliases.

I installed it for my Ubuntu. And for folders structure:

enter image description here

ran this from project learning_antlr4 level:

grun qwe tokens -tokens < qwe/qwe.tokens

The output was empty.

What do I wrong? Where that aliases are saved?

Upvotes: 1

Views: 2879

Answers (2)

Jagmit Swami
Jagmit Swami

Reputation: 41

This Code works for Java Maven antlr4

import java.io.IOException;
import org.antlr.v4.gui.Trees;
import org.antlr.v4.runtime.CharStream;
import org.antlr.v4.runtime.CharStreams;
import org.antlr.v4.runtime.CommonTokenStream;

public class GrunGui {
    
    public static void main(String[] args) throws IOException {
        
        // input source (can be different in your case)
        String inputfilepath = "<your file path>";
        
        // your input type can be different, adjust code according to your input source
        CharStream charStreamInput = CharStreams.fromFileName(inputfilepath);
        
        // replace ExampleLexer and ExampleParser with your own lexer and parser
        ExampleLexer lexer = new ExampleLexer(charStreamInput);
        
        CommonTokenStream tokens = new CommonTokenStream(lexer);
        
        ExampleParser parser = new ExampleParser(tokens);
        
        // replace YourContext and .yourStartRuleMethod() method according to your own grammar file
        ExampleParser.YourContext ctx = parser.yourStartRuleMethod();
        
        Trees.inspect(ctx, parser);
    }
}

This code will open grun GUI.

Upvotes: 0

Mike Cargal
Mike Cargal

Reputation: 6785

Assuming you have the grun alias set up (if not, see the QuickStart at the tops of this page https://www.antlr.org):

What you want is to view the token stream produced by the Lexer processing your input (not your qwe.tokens file)

qwe.txt:

total_sales>qwe

ANTLR on  master [✘+?] 
➜ antlr4 qwe.g4      

ANTLR on  master [✘+?] 
➜ javac *.java

ANTLR on  master [✘+?] 
➜ grun qwe tokens -tokens < qwe.txt
[@0,0:10='total_sales',<COLUMN>,1:0]
[@1,11:11='>',<OPERATOR>,1:11]
[@2,12:14='qwe',<COLUMN>,1:12]
[@3,15:14='<EOF>',<EOF>,1:15]

AS you can see... both total_sales and qwe are recognized as COLUMN tokens,

Upvotes: 1

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