Enum ScanError 

pub enum ScanError {
    InvalidEscape {
        byte_offset: usize,
        seq: String,
    },
    UnterminatedCapture {
        byte_offset: usize,
    },
    EmptyCapture {
        byte_offset: usize,
    },
    InvalidCaptureName {
        byte_offset: usize,
        name: String,
    },
    UnknownCaptureKind {
        byte_offset: usize,
        name: String,
    },
    UnknownConstructor {
        byte_offset: usize,
        name: String,
    },
    MalformedCaptureBody {
        byte_offset: usize,
        message: String,
    },
    CallShape(ValidationError),
    NestingTooDeep {
        byte_offset: usize,
        what: &'static str,
    },
}

An error encountered while scanning a template interior or a capture body.

Variants

InvalidEscape

An invalid escape sequence (e.g. \q). seq is the text the source actually wrote, sliced from it, not a re-format! of a guessed byte.

Fields

byte_offset: usize

seq: String

UnterminatedCapture

An unterminated capture {... (no closing }).

Fields

byte_offset: usize

EmptyCapture

An empty capture {}.

Fields

byte_offset: usize

InvalidCaptureName

A capture whose name is not an identifier (§4.1).

Fields

byte_offset: usize

name: String

UnknownCaptureKind

A capture body naming a parser that does not exist.

Fields

byte_offset: usize

name: String

UnknownConstructor

A capture body calling a constructor that does not exist (§7.5).

Fields

byte_offset: usize

name: String

MalformedCaptureBody

A capture body that is not a parser expression at all.

Fields

byte_offset: usize

message: String

CallShape(ValidationError)

A constructor call in a capture body whose arguments do not have §7.5’s shape. Carries the ValidationError check_call produced, so the code and the message are the same ones a top-level call would report.

NestingTooDeep

Nesting past MAX_NESTING.

what is which nesting hit the bound — templates, {, or (. A diagnostic that states the wrong thing is worse than a vague one: a csv( thirty-three deep is a parenthesis bound, and calling it template nesting misnames the limit in text that holds one template.

Fields

byte_offset: usize

what: &'static str

Implementations

impl ScanError

pub fn byte_offset(&self) -> usize

The byte offset in the scanned text this error is anchored at.

pub fn shifted(self, delta: usize) -> ScanError

The same error, anchored delta bytes later.

A nested template’s interior is scanned in its own offsets: the scanner is handed the text between the backticks and knows nothing about where that text sits in the template that contains it. The caller does know, and this is how the two are joined. Without it every caret under a nested template lands short by the nested interior’s own offset.

pub fn code(&self) -> DiagCode

The diagnostic this error is reported under.

Exhaustive on purpose. A wildcard would flatten every variant it caught into DiagCode::TemplateScan (I030) and leave the codes ADR-051 allocates for these cases — InvalidCaptureName I011, UnknownCaptureKind I012, UnknownConstructor I013 — constructed nowhere in the tree. A match with no wildcard is what stops the next variant from silently inheriting I030.

pub fn unknown_parser_name(&self) -> Option<&str>

The parser name this error could not resolve, when that is what went wrong — the word a “did you mean” would replace (ADR-132).

Exhaustive, so a variant added later has to answer: a name that reaches a caller by accident is a fix offered for the wrong span, and a name that does not reach it is a fix silently not offered.

Trait Implementations

impl Clone for ScanError

fn clone(&self) -> ScanError

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ScanError

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

Formats the value using the given formatter.

impl Display for ScanError

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

Formats the value using the given formatter.

impl Eq for ScanError

impl Error for ScanError

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 PartialEq for ScanError

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for ScanError