too bad - one more plugin that doesn't work properly with my beloved IntelliJ: ANTLR works grammar development.
I inquired with Terence Parr, the definitive source for all ANTLR infos - and he admitted that the ANTLR plugin for IntelliJ has been abandoned, as it was "too difficult to get it to run properly".
Rescue is on its way - ANTLRv3IDE for Eclipse (3.5 onwards). Great plugin, great docu.
