pl0 is an open source compiler for the PL/0 programming language. It is small, simple and educational compiler that produces native executables for the macOS operating system.
For a description of the programming language, Wikipedia describes it best:
PL/0 is a programming language, intended as an educational programming language, that is similar to but much simpler than Pascal, a general-purpose programming language.
Download the compiler from the releases page.
Extract the archive into /usr/local, creating a pl0 installation in /usr/local/pl0.
For Example:
tar -C /usr/local -xzf pl0-$VERSION.darwin.amd64.tar.gz
Add /usr/local/pl0/bin to the PATH environment variable:
export PATH=$PATH:/usr/local/pl0/bin
Compile and run a sample program:
pl0 /usr/local/pl0/example/square.pl0 ./square