Enum CommandError 

pub enum CommandError {
    UnknownCommand,
    KindMismatch {
        expected: &'static str,
        actual: &'static str,
    },
    MissingTarget,
    MotionFailed,
    User(String),
    InvalidArgs(&'static str),
    BadArgs(String),
    Plugin(String),
    Cancelled,
    Core(CoreError),
    Protocol(ProtocolError),
}

Why a grammar invocation failed. See the module docs for the no-effect-on-error contract every variant shares.

Variants

UnknownCommand

The invocation named a crate::CommandId (or a motion / operator / text-object id) that is not in the crate::CommandRegistry – e.g. a plugin contribution that has since been unloaded, or a stale id carried in a recorded macro.

KindMismatch

The id resolved, but to a registration of a different kind than the call site needs (an operator id passed where a motion was expected). A programming error in the caller, not a user error.

Fields

expected: &'static str

The kind the call site required, as its registry label ("motion", "operator", "text-object", "ex-command", "action").

actual: &'static str

The kind the id actually names, same label vocabulary.

MissingTarget

An operator invocation carried neither a crate::Target nor a crate::Range, so there is nothing to operate on. The keystroke parser never builds such an invocation; this guards programmatic callers (plugins, replayed macros).

MotionFailed

VM.3L: a motion couldn’t move (vim beeps): j on the last line, k on the first. The dispatcher commits no effect, so an operator it was feeding is cancelled — vim deletes nothing for dj on the last line, where returning the cursor would have deleted that line.

User(String)

VM.3d-2: a command failed with a message the user should see — vim’s E486: Pattern not found, E35: no previous regular expression. Like every error, no effect is committed (an operator fed by a failing n deletes nothing, as in vim); unlike the others, the host echoes it.

InvalidArgs(&'static str)

The evaluator received crate::Args of the wrong shape, or args that do not fit the document (the common case is a position computed past the end of the buffer). The static string names what was wrong; it is for logs, not the user.

BadArgs(String)

An ex-command’s parse_args callback rejected the input. Carries the human-readable reason; the parser front-end surfaces it through ExCommandError::BadArgs.

Plugin(String)

A WASM-plugin grammar contribution failed at apply / parse_args (PH7.7c): a guest-returned err, a fuel/epoch trap (the Reflex-budget runaway guard), a boundary-conversion failure, or a dead plugin. The dispatcher treats it like any evaluator error — no Effect is committed, the contribution is a no-op (graceful degradation, plugin-host.md §8), and the reason is logged. Built-in grammar never produces this.

Cancelled

The evaluator observed a cancelled crate::CancellationToken and returned early. By DESIGN.md §5.2.5, no Effect is committed; the document is left at the version the keystroke arrived at, exactly as if the user had not pressed the key.

Core(CoreError)

A buffer-model failure from [lattice_core] (I/O, nothing to undo/redo, a core-level cancellation) surfaced through ?.

Protocol(ProtocolError)

A protocol-layer failure from [lattice_protocol] (unknown document, out-of-bounds position, stale version) surfaced through ?.

Trait Implementations

impl Debug for CommandError

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

Formats the value using the given formatter.

impl Display for CommandError

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

Formats the value using the given formatter.

impl Error for CommandError

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.

impl From<CoreError> for CommandError

fn from(source: CoreError) -> Self

Converts to this type from the input type.

impl From<ProtocolError> for CommandError

fn from(source: ProtocolError) -> Self

Converts to this type from the input type.