Getting the line number in the ParserVisitor?

antlr parse-tree
i_have_no_idea_what_i'm_doing picture i_have_no_idea_what_i'm_doing · Nov 5, 2013 · Viewed 10.8k times · Source

I'm trying to get line numbers for more specific error messages in my ParserVisitor (visits the parse tree generated by antlr). However, all I have in this class is the context ctx, and I can do things like ctx.getText() but not getLine(). Is there a way to do this?

Can ctx.getPayload() be used here? If so, how?

Edit: I'm using ANTLR 4 to create java files.

Trying to access the line number in a visitor in a method such as this:

@Override 
public Type visitStatAssign(@NotNull BasicParser.StatAssignContext ctx) {
...
// some semantic error detected
int lineNo = ...
System.err.("Semantic error at line " + lineNo); 
}

Edit 2: My lexer and parser rules are fairly standard, for example in the lexer:

INT : 'int' ;
CHAR : 'char' ;
BOOL : 'bool' ;
STRING : 'string' ;

...is in the parser rule baseType:

baseType : INT | CHAR | BOOL | STRING ;

Answer

njlarsson picture njlarsson · Jan 11, 2014

You can get the first token in the rule with ctx.start or ctx.getStart(). Then use getLine() on the token to get the line number (and getCharPositionInLine() to get the column).

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