No module named antlr4 in python 2.7

Question

I would like to use ANTLR4 with Python 2.7 and for this I did the following:

1. I installed the package antlr4-4.6-1 on Arch Linux with sudo pacman -S antlr4.

2. I wrote a MyGrammar.g4 file and successfully generated Lexer and Parser Code with antlr4 -Dlanguage=Python2 MyGrammar.g4

3. Now executing for example the generated Lexer code with python2 MyGrammarLexer.py results in the error ImportError: No module named antlr4.

What could to be the problem? FYI: I have both Python2 and Python3 installed - I don't know if that might cause any trouble.

Drone

Answer 1

You need to install antlr4 for python through pip:

sudo pip install antlr4-python2-runtime

If you don't have pip on you system, install it first with:

sudo pacman -S python2-pip

Saddler

I tried this but sadly it did not work. After executing the pip install command it says Requirement already satisfied: antlr4-python2-runtime in /usr/lib/python3.6/site-packages. It might be the case that pip does not work correctly for the two python versions but I don't know how to figure out the problem... – Drone

I just copied the antlr4 files from /usr/lib/python3.6/site-packages/ to /usr/lib/python2.7/site-packages/ and this solved the problem! – Drone

@Drone Maybe you could try sudo pip2 install antlr4-python2-runtime, because this would call pip for Python2. – Saddler

Oh, perfect! I didn't know that this is possible. Thank you :) – Drone

Answer 2

The problem was that antlr4 was only installed for Python3 and not Python2. I simply copied the antlr4 files from /usr/lib/python3.6/site-packages/ to /usr/lib/python2.7/site-packages/ and this solved the problem!

Drone

Answer 3

try:

pip install antlr4-python2-runtime

or:

python -m pip install antlr4-python2-runtime

Peasecod