The purpose of this page is to collect problems and solutions that users on various platforms have had with the Lingua Franca tools. If you have suggestions for additions to this page, please submit a pull request.
Environment Issues
The Lingua Franca tools rely on being able to invoke various external programs such as cmake, target-language compilers, Python, and Node.js. If any of these programs is missing, you will get an error message suggesting that you install the program. If you install the program and the error message persists, this usually means that the program is not visible in the environment in which the Lingua Franca tool is being run.
The simplest approach to diagnosing the problem is to first verify that the command-line tools work. For example, on the command line:
$ lfc --version lfc 0.2.1 $ cmake --version cmake version 3.22.2 $ lfc src/MyFile.lf ... successful compile ...
If you then have trouble compiling the same file using Epoch or the Visual Studio Code extension, then those tools are executing in a different environment that may not have the same PATH variable and may, for example, fail to find some external program or invoke a different version of that program.
On many platforms, one way to ensure that Epoch and the Visual Studio Code extension use the same environment as the command-line tools is to invoke them on the command line. For example, on a Mac, you can invoke Epoch and Visual Studio Code as follows:
$ open -a epoch $ code .
This way, the tools inherit the environment from the shell from which you invoke them. Often, that environment is quite different from what you get if, for example, you invoke the tools by double clicking on their icons.
Target-Language Specific Troubleshooting
Wrong Python version
Many problems first encountered by Python users are caused by having multiple versions of Python installed on your platform. First, you should ensure that you have Python 3 installed. On the command line, you should see something like this:
$ python3 --version Python 3.9.12
Then make sure your IDE (Epoch or VS Code) or your command-line compiler lfc is invoked in the same environment as this command line (start the IDEs in the same shell).
Note that your Python installation may assume the command python instead of python3. As long as that version of Python is still 3, it should work.
LinguaFrancaBase not installed
When you try to run the generated Python program, you might see this:
No module named 'LinguaFrancaBase'. Install using "pip3 install LinguaFrancaBase".
Follow the instructions:
$ pip3 install LinguaFrancaBase
If this still does not work, then possibly your version of pip3 does not match your Python version. Check:
$ pip3 --version pip 22.0.4 from /usr/local/lib/python3.9/site-packages/pip (python 3.9)
If pip3 does not match, you install LinguaFrancaBase instead using:
python3 -m pip install LinguaFrancaBase
This will ensure that it is installed for the same version of Python.
