Command-line tools

Commands assume xen is on PATH. From a distribution directory, substitute ./bin/xen; from the repository, use compiler/dist/xen.

Command	Purpose
xen version or xen --version	Show the installed version
xen check file.xen	Find errors before execution
xen run file.xen	Run immediately
xen build file.xen -o app	Make a standalone executable
xen test [file.xen or directory or std.module]	Run tests

Successful check and build commands produce no output. Without -o, build writes a.out in the working directory. An existing output file is overwritten. run uses the current working directory and standard input/output, removing its temporary executable when the program exits.

Program arguments

xen run word_count.xen -- input.txt
xen build word_count.xen -o word-count
./word-count input.txt

Before -- are Xen options; after it are your program’s arguments. Read them with std.env.args() or arg_count() and arg(index). The first argument has index 0; the executable name is excluded. An invalid arg index is a runtime error.

Choose the execution environment

The default target is your installed Xen compiler’s Linux architecture. check, build, run, and test accept --target=x86_64-linux and --target=aarch64-linux. arm64-linux is an alias for the latter.

xen build hello.xen --target=aarch64-linux -o hello-arm64

Run the output on a compatible Linux machine. Selecting another CPU does not automatically make it executable on the current machine. AArch64 support is experimental and validation on physical devices is ongoing. macOS and Windows are unsupported.

Select tests

xen test searches the current directory. Narrow names with --filter text. See testing.

Optional build options

Normal programs can use the defaults. For blocks you explicitly mark as #scope[opt] { ... }, build, run, and test use --opt=basic by default. Disable it with --opt=off. Unmarked code is unaffected.

--opt-report prints application information to stderr. --opt-cache=directory stores a build cache in that directory. Both require basic and are unavailable for check. These options are optional when learning and using the language.

Exit status and help

Status	Meaning
0	Success
1	Code, runtime, or test error, or no matching tests
2	Invalid command usage

run propagates the program’s exit status. Panics and ordinary runtime errors usually exit 1. There is no separate --help option. Running xen without arguments prints usage to stderr and exits 2.