Enum Action

pub enum Action {
    Help(String, PathBuf),
    List(String),
    Execute {
        launcher_path: PathBuf,
        executable: PathBuf,
        args: Vec<String>,
    },
}

Represents the possible outcomes based on CLI arguments.

Variants

Help(String, PathBuf)

The help string for the Python Launcher along with the path to a Python executable.

The executable path is so that it can be executed with -h to append Python’s own help output.

List(String)

A string listing all found executables on PATH.

The string is formatted to be human-readable.

Execute

Details for executing a Python executable.

Fields

launcher_path: PathBuf

The Python Launcher used to find the Python executable.

executable: PathBuf

The Python executable to run.

args: Vec<String>

Arguments to the executable.

Implementations

impl Action

pub fn from_main(argv: &[String]) -> Result<Self>

Parses CLI arguments to determine what action should be taken.

The first argument – argv[0] – is considered the path to the Launcher itself (i.e. Action::Execute::launcher_path).

The second argument – argv.get(1) – is used to determine if/what argument has been provided for the Launcher.

Launcher Arguments

-h/--help

Returns Action::Help.

The search for the Python executable to use is done using crate::find_executable with an RequestedVersion::Any argument.

--list

Returns Action::List.

The list of executable is gathered via crate::all_executables.

Version Restriction

Returns the appropriate Action::Execute instance for the requested Python version.

crate::find_executable is used to perform the search.

No Arguments for the Launcher

Returns an Action::Execute instance.

As a first step, a check is done for an activated virtual environment via the VIRTUAL_ENV environment variable. If none is set, look for a virtual environment in a directory named by DEFAULT_VENV_DIR in the current or any parent directories.

If no virtual environment is found, a shebang line is searched for in the first argument to the Python interpreter. If one is found then it is used to (potentially) restrict the requested version searched for.

The search for an interpreter proceeds using crate::find_executable.

Errors

If -h, --help, or --list are specified as the first argument but there are other arguments, crate::Error::IllegalArgument is returned.

If no executable could be found for Action::Help or Action::List, crate::Error::NoExecutableFound is returned.

Panics

• If a writeln! call fails.
• If the current directory cannot be accessed.

Trait Implementations

impl Clone for Action

fn clone(&self) -> Action

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Action

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Hash for Action

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for Action

fn eq(&self, other: &Action) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for Action

impl StructuralPartialEq for Action