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GuideInstall Calx

Install Calx

Build the calx command from source on Windows or Linux, put it on your PATH, and check that it runs a program.

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Calx has no releases yet, so you build the compiler from source. It’s one CMake build. Calx runs on Windows and Linux, on 64-bit x86.

What you need

Section titled “What you need”
  • Git, to get the source.
  • CMake 3.20 or later, and Ninja.
  • clang and lld, from LLVM 18 or later. Calx compiles programs to C and has clang build that C, so you need clang to run programs, as well as to build the compiler.
  • On Windows, Visual Studio or its Build Tools, with the “Desktop development with C++” workload. clang links programs against the C runtime and the Windows SDK that come with it. You can get them from visualstudio.microsoft.com.
  • Python 3, only if you want to run the test suite.

On Ubuntu or Debian:

Shell
sudo apt install git cmake ninja-build clang lld

If clang --version says your clang is older than 18, apt.llvm.org has newer ones.

On Windows, with winget:

Shell
winget install Git.Git
winget install Kitware.CMake
winget install Ninja-build.Ninja
winget install LLVM.LLVM

LLVM’s installer puts clang in C:\Program Files\LLVM\bin. Add that folder to your PATH, or set CALX_CC to the full path of clang.exe.

Release builds use x86-64-v3 instructions, so the programs they make need a processor with AVX2, as most made since 2015 have. Debug builds run on any 64-bit x86 processor.

Build the compiler

Section titled “Build the compiler”
Shell
git clone https://github.com/ellipog/calx
cd calx
cmake -S compiler -B build/compiler -G Ninja -DCMAKE_CXX_COMPILER=clang++
ninja -C build/compiler

That makes build/compiler/calx, or calx.exe on Windows. It finds its runtime in the checkout it was built from, so leave the checkout where it is. If you move it, set CALX_HOME to the new place.

Add the build/compiler folder to your PATH. The guide and the reference call the command calx.

Check that it works

Section titled “Check that it works”

From the checkout:

Shell
calx run tests/basics/hello.calx

It prints hello, calx, then four more lines. The first run builds Calx’s runtime as well as the program, which takes a moment. After that, a program that hasn’t changed starts in milliseconds.

If it says it can’t find clang, put clang on your PATH, or set CALX_CC to its full path.

Where builds go

Section titled “Where builds go”

The compiler caches what it builds. The cache is in %LOCALAPPDATA%\calx\cache on Windows, and in ~/.cache/calx on Linux, or under XDG_CACHE_HOME if that’s set. CALX_CACHE puts it somewhere else. Deleting it is always safe: the next build makes it again.

The tests

Section titled “The tests”

python tests/run.py builds the compiler and runs the test suite, which includes every example in these docs. CI runs it in debug and release builds, on Windows and Linux.

Next

Section titled “Next”
  • Set up your editor: the VS Code extension highlights Calx and shows errors as you type (editor support).
  • Start the guide with Getting started, which writes a first program.