Antrlv4 hangs while parsing PostgreSQLParser.g4

[Mercurial]

Hi,

I got the PostgreSQLParser.g4 file from here https://github.com/antlr/grammars-v4/blob/master/sql/postgresql/PostgreSQLParser.g4.

I believe that in that grammar "root" is the start rule.

so I run this command on the command line

antlr4-parse PostgreSQLParser.g4 root

and then I get around 600 lines of warnings like

warning(125): PostgreSQLParser.g4:51:12: implicit definition of token SEMI in parser
warning(125): PostgreSQLParser.g4:183:6: implicit definition of token MetaCommand in parser
warning(125): PostgreSQLParser.g4:183:18: implicit definition of token EndMetaCommand in parser
warning(125): PostgreSQLParser.g4:187:6: implicit definition of token CALL in parser
warning(125): PostgreSQLParser.g4:191:6: implicit definition of token CREATE in parser

and then I enter a sample sql statement like

select id from person where age > 10;

and press enter.

but that doesn't do anything

I can just a a cursor blinking.

and then when I do ctrl-c a couple of times

I get this message.

Exception in thread "main" java.lang.IllegalStateException: A lexer interpreter can only be created for a lexer or combined grammar.

Am I doing something wrong here?

[Michael Rachow]

Hi Mercurial,

You have to provide both parts of the PostgreSQL grammar,
e.g. lexer and parser grammar.

antlr4-parse PostgreSQLLexer.g4 PostgreSQLParser.g4 ...

All the implicit warnings are a result of the missing definition from the lexer part of this splitted grammar.

Regards,
Michael