Enum NarjuError 

pub enum NarjuError {
    Parse(String),
    UnboundVar {
        level: usize,
        env_len: usize,
    },
    TypeError {
        op: &'static str,
        expected: &'static str,
        actual: String,
    },
    Stage(String),
    Io(Error),
    Throw(Val),
}

Any error the evaluator or its entry points can produce.

Errors abort the current top-level evaluation and unwind the CK machine’s continuation stack. Two forms survive in-language: a NarjuError::Throw raised inside a catch arrives at the catch site with its payload intact, and any other error inside a catch arrives stringified via Display. The #[error] strings here are therefore user-visible surface, both at the REPL and through catch.

Variants

Parse(String)

Malformed source, from the reader or from lowering (which reports unbound names at parse time with their surface names).

UnboundVar

A Var index past the end of the runtime environment. Lowering makes this unreachable from surface source; it can only arise from hand-built or mis-translated Exp trees, so the message reports raw indices — there is no name to report.

Fields

level: usize

The out-of-range Var index.

env_len: usize

Environment length at the point of lookup.

TypeError

A primitive applied to a value of the wrong shape.

Fields

op: &'static str

Surface name of the offending operation (e.g. "car").

expected: &'static str

What the operation accepts.

actual: String

Compact description of what it got — Val::short_desc output, which never dumps a full code tree.

Stage(String)

A staging-discipline violation: lifting the unliftable, running at the wrong level, a malformed trans/evalms argument, and the like.

Io(Error)

A failure from the underlying I/O implementation (read, read-file, print).

Throw(Val)

(throw v): a user-raised error carrying a first-class Val payload. unwind_to_catch unpacks the payload structurally into (error <payload> ()) instead of stringifying it, so structured signals like (unbound . name) survive to the catch site.

Trait Implementations

impl Debug for NarjuError

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

Formats the value using the given formatter.

impl Display for NarjuError

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

Formats the value using the given formatter.

impl Error for NarjuError

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<Error> for NarjuError

fn from(source: Error) -> Self

Converts to this type from the input type.