Callisto extends Lua 5.4's standard library by adding new modules and facilities to the interpreter. It includes a file system library to manage and manipulate files and directories, a process library to find active processes and manipulate signals, and a JSON manipulation library (lua-cjson) among many more.
It is a standalone interpreter designed for people using Lua as a general scripting language, rather than using it embedded into another program, which is what Lua was designed for. Perhaps you could think of it as a replacement for Python.
First and foremost, Callisto tries to be:
- a runtime environment for Lua that includes most features people would need out of the box, all in one executable with zero dependencies
- a library that works well and integrates well with the Lua language and its standard library, and is easy to use for those who have no prior experience with C
Callisto relies on APIs specified in the POSIX specification; therefore it cannot be used on operating systems that are not POSIX-compliant (like Microsoft Windows).
To build Callisto, all you need is a C99 compiler. The configure
script will check for the presence of various compilers before
building, to decide which one to use.
The compilers checked are clang, followed by gcc, followed by cc. If
you have a compiler at a custom path that you would like to use over
the system C compiler, just pass -c /path/to/compiler to the
configure script before you build. The compiler must support gcc-like
command line arguments.
Callisto has zero runtime dependencies, unless you built it with support for GNU libreadline*. Lua 5.4 is statically linked in. This means that the same binary will work across different Linux distributions.
*libreadline support can be enabled at build time, but is disabled by
default. To force building with libreadline support, pass the
-wreadline flag to the configure script.
Callisto is distributed as source-only, but it's very easy to build it yourself. Just make sure you have a compiler such as gcc installed, as well as git for downloading the source code and make for compiling.
First, obtain a copy of the source code using the following command:
git clone https://git.sr.ht/~jeremy/callisto
After that, run
./configure
make
to compile Callisto and all its dependencies.
To install it, run make install as the root user in the source code
directory. If you choose not to install it, you can still invoke it in
the current directory.
Users of Arch Linux can install the AUR package:
https://aur.archlinux.org/packages/callisto-git
If you use Nix, you can use the flake:
nix profile install sourcehut:~jeremy/callisto
The standalone Callisto interpreter is called csto. This is the main
way to run Lua programs using the Callisto libraries. Running it
without arguments will start a read-eval-print loop so you can execute
chunks of code interactively.
csto works just like the standalone Lua 5.4 interpreter. To execute
code in a file, run csto file where file is the name of the file
containing code you want to run.
Alternatively, put #!/usr/bin/env csto at the top of your script,
make it executable with chmod +x, and then you can run the script as
if it was a standalone executable, for example ./script.lua.
Library documentation can be found here: https://jtbx.github.io/callisto/doc
If you find a bug, please submit a report using the ticket tracker: https://todo.sr.ht/~jeremy/callisto
If you don't have a sourcehut account, you can file a ticket by sending an email to ~jeremy/callisto@todo.sr.ht.
Send a patch to ~jeremy/callisto-devel@lists.sr.ht using
git send-email. Preferred code style is
detailed in the style.md document but is not required. Thanks :)