Recently I tried to write ANTLR grammar file (.g) using the ANTLR Editor for eclipse available at http://antlreclipse.sourceforge.net/updates/.
I found this editor to be useful only for highlighting the syntax (unless I always keep compiling manually).
Is there any eclipse based ANTLR editor equivalent to ANTLR Works and compatible with ANTLR 3?
You can try AntrDT also recommended on Antlr3 web site.
For Antlr4 there is also antlr4ide.