Enum AddLessonError 

pub enum AddLessonError {
    InvalidId(String),
    NotACourse(PathBuf),
    AlreadyExists(PathBuf),
    Write(Error),
}

Why a lesson could not be added to a course.

The three refusals are kept distinct from a genuine write failure so the cli can frame each: an InvalidId, a NotACourse, or an AlreadyExists is a user-correctable refusal caught at the boundary before any write, whereas a Write is an underlying I/O fault.

Variants

InvalidId(String)

The lesson id is not a safe slug (empty, or containing a path separator, .., whitespace, or punctuation), so it is refused before any write (§1.3.1) rather than escaping the course’s lessons/ directory or breaking the manifest’s TOML. Carries the rejected id.

NotACourse(PathBuf)

The target directory is not a course: it has no blendtutor.toml to register the lesson in, so the add is refused before any write (§1.3.1) rather than leaving an orphan lesson in a non-course directory. Carries the directory. (Run blendtutor init first, or cd into a course.)

AlreadyExists(PathBuf)

A file already exists at the target path — the lesson itself, or its eval_-prefixed sibling suite — so the command refuses to overwrite it (no clobber), before any write to that path. Carries the course-relative path that is already taken.

Write(Error)

A filesystem operation failed while writing the lesson file or registering it in the manifest.

Trait Implementations

impl Debug for AddLessonError

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

Formats the value using the given formatter.

impl Display for AddLessonError

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

Formats the value using the given formatter.

impl Error for AddLessonError

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0: use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.