Enum ExprError 

#[non_exhaustive]
pub enum ExprError {
    NotAnExpression,
    Unclosed,
    Empty,
    MissingSource,
    UnterminatedString {
        quote: char,
    },
    InvalidFunctionName {
        name: String,
    },
    UnclosedCall {
        function: String,
    },
    InvalidArgument {
        function: String,
        position: usize,
        cause: Box<ExprError>,
    },
    MissingNamespace {
        text: String,
    },
    NotAReference {
        text: String,
    },
    UnknownNamespace {
        namespace: String,
    },
    MaterialNamespace {
        namespace: String,
        name: String,
    },
    EmptyName {
        namespace: String,
    },
    InvalidName {
        name: String,
    },
    InvalidProperty {
        property: String,
    },
    InvalidPipeStage {
        stage: String,
    },
}

Why a ${...} occurrence is not a usable expression.

Each variant names one decision the parser made, so a caller can tell an unknown namespace from a malformed name without reading the message text. Display renders the sentence a diagnostic shows.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

NotAnExpression

The text is not wrapped in ${ and }.

Unclosed

Nothing closes the occurrence.

Empty

The braces hold nothing.

MissingSource

A pipeline has stages but nothing to compute them from.

UnterminatedString

A quoted string never closes.

Fields

quote: char

The quote character that opened it.

InvalidFunctionName

The text before a ( is not a function name.

Fields

name: String

The text as written.

UnclosedCall

A function call never closes its parentheses.

Fields

function: String

The function named.

InvalidArgument

One argument to a function call is not an expression.

Fields

function: String

The function named.

position: usize

Which argument, counting from one.

cause: Box<ExprError>

Why that argument is not an expression.

MissingNamespace

A name stands on its own, with no namespace in front of it.

Fields

text: String

The text as written.

NotAReference

The text is neither a literal nor the start of a reference.

Fields

text: String

The text as written.

UnknownNamespace

The namespace is not one this DSL has.

Fields

namespace: String

The namespace as written.

MaterialNamespace

A reference names material, which is not a namespace.

Fields

namespace: String

The namespace as written, which may be a misspelling.

name: String

The name that followed it.

EmptyName

Nothing follows the namespace.

Fields

namespace: String

The namespace as written.

InvalidName

The name is not an identifier.

Fields

name: String

The name as written.

InvalidProperty

The property is not an identifier.

Fields

property: String

The property as written.

InvalidPipeStage

A pipe stage is not a function name.

Fields

stage: String

The stage as written.

Implementations

impl ExprError

pub fn suggestion(&self) -> Option<RefType>

The namespace this failure was close enough to have been meant as.

An editor offers it as a fix. The message says the same thing, so the two cannot disagree.

Trait Implementations

impl Clone for ExprError

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ExprError

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

Formats the value using the given formatter.

impl Display for ExprError

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

Formats the value using the given formatter.

impl Eq for ExprError

impl Error for ExprError

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 ExprError

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for ExprError