[antlr-interest] Composite Grammar [C Target]

[Justin Murray]

Hello,

I'm trying to use composite grammars, and can't seem to get off of the
ground. Basically, I have two separate parsers. One preprocesses the
source, and the other compiles it. Naturally, they have a few tokens in
common, such as a newline, and I'd prefer to only define that token
once. This sounds to me like exactly what composite grammars were
designed to do. So I made a CommonTokens.g:

lexer grammar CommonTokens;

NEWLINE_ :  ('\r'? '\n');

Then in my grammar, I added an import:

grammar AerobasicPreprocessor;
import CommonTokens;

options { language=C;  }

line : SOMEOTHERTOKENS_ NEWLINE_;
...


When I run the ANTLR tool on this grammar, I get some less than helpful
errors:

error(100): AerobasicPreprocessor.g:4:1: syntax error: antlr:
org.antlr.runtime.EarlyExitException
error(150):  grammar file AerobasicPreprocessor.g has no rules
error(100): AerobasicPreprocessor.g:0:1: syntax error: assign.types:
org.antlr.runtime.EarlyExitException
org\antlr\grammar\v3\DefineGrammarItemsWalker.g: node from line 326:1
required (...)+ loop did not match anything at input ';'

What am I doing wrong?

Thanks,

- Justin