I can confirm that the IntelliJ ANTLR 4 plugin does work in PyCharm if you edit the plugin.xml. Here's what I did:
1) Downloaded the plugin zip file from the IntelliJ plugin repository
2) Unzipped the file
3) In the lib directory, extracted the intellij-plugin-v4.jar file (use any zip extractor)
4) Inside the extracted jar directory, go into META-INF and edit plugin.xml. Uncomment out the line mentioned above.
5) Recreate the jar file (zip up the extracted directories again, then rename the file to .jar)
6) Recreate the original plugin zip file again by zipping up the extracted directory
7) Import into PyCharm using the load plugin from disk option in the plugin setttings
Finally, in any grammar where you want a Python target generated, include in the .g4 file:
options
{
language=Python3;
}
Or
options
{
language=Python2;
}
Depending on what version of Python you're targeting.
The "auto-generate parser upon save" option doesn't seem to work, but you can still generate the parser through the Tools menu.