This is the easiest way.
Install prerequisites and LFortran (works on both Linux and Mac):
conda create -n lfortran python=3.7 pytest llvmlite prompt_toolkit
conda activate lfortran
pip install antlr4-python3-runtime
tar xzf lfortran-0.1.tar.gz
cd lfortran-0.1
pip install .
Now the lfortran environment has the lfort compiler available.
Optional: run tests:
py.test --pyargs lfortran
This works both on Linux and a Mac:
conda create -n lfortran python=3.7 pytest llvmlite prompt_toolkit
conda activate lfortran
pip install antlr4-python3-runtime
Install Java and then ANTLR, say, into ~/ext:
export CLASSPATH="$HOME/ext/antlr-4.7-complete.jar:$CLASSPATH"
Build:
./build.sh
Run tests:
py.test
Run prompt:
./prompt