Enum HomError 

#[non_exhaustive]
pub enum HomError {
    NodeNotMapped(u32),
    ImageNodeMissing {
        src: u32,
        tgt: u32,
    },
    AnchorMismatch {
        src: u32,
        tgt: u32,
        src_anchor: Name,
        tgt_anchor: Name,
    },
    ArcNotPreserved {
        parent: u32,
        child: u32,
        mapped_parent: u32,
        mapped_child: u32,
    },
    FanNotPreserved {
        hyper_edge_id: String,
        parent: u32,
    },
    AttributeMismatch {
        src: u32,
        tgt: u32,
    },
    RootNotPreserved {
        src: u32,
        mapped: u32,
        cod: u32,
    },
    RowMapMalformed {
        table: String,
        detail: String,
    },
    ForeignKeyNotPreserved {
        edge: String,
        mapped_src: usize,
        mapped_tgt: usize,
    },
    ComposeNodeMismatch(u32),
    ComposeRowMismatch {
        table: String,
        detail: String,
    },
}

Error raised when an instance homomorphism fails its structural checks or when two homomorphisms cannot be composed.

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.

NodeNotMapped(u32)

The node map is not total: a domain node has no image.

ImageNodeMissing

The node map sends a domain node to a codomain node that does not exist.

Fields

src: u32

The domain node.

tgt: u32

The claimed image, absent from the codomain.

AnchorMismatch

A domain node and its image sit over different schema vertices, so the map does not preserve anchors.

Fields

src: u32

The domain node.

tgt: u32

Its image in the codomain.

src_anchor: Name

The domain node’s anchor.

tgt_anchor: Name

The image node’s anchor.

ArcNotPreserved

A domain arc has no corresponding arc in the codomain under the map, so the map does not preserve the tree structure.

Fields

parent: u32

The domain arc’s parent node.

child: u32

The domain arc’s child node.

mapped_parent: u32

The image of the parent.

mapped_child: u32

The image of the child.

FanNotPreserved

A domain fan has no corresponding fan in the codomain under the map.

Fields

hyper_edge_id: String

The hyper-edge the fan instantiates.

parent: u32

The domain fan’s parent node.

AttributeMismatch

A domain node (or row) and its image carry different attribute values, so the map does not preserve the attribute assignment.

Fields

src: u32

The domain node id (W-type) or row index (F-instance).

tgt: u32

The image node id or row index.

RootNotPreserved

The map does not send the domain root to the codomain root.

Fields

src: u32

The domain root.

mapped: u32

Its image.

cod: u32

The codomain root.

RowMapMalformed

A table present in the domain has no row map, or the row map disagrees with the table’s row count, or the codomain lacks the table.

Fields

table: String

The table (schema vertex) whose row map is malformed.

detail: String

What is wrong.

ForeignKeyNotPreserved

A foreign key of the domain is not preserved by the row maps.

Fields

edge: String

A rendering of the edge whose foreign key is broken.

mapped_src: usize

The image of the source row index.

mapped_tgt: usize

The image of the target row index.

ComposeNodeMismatch(u32)

Two homomorphisms cannot be composed because the image of the first is not in the domain of the second.

ComposeRowMismatch

Two F-instance homomorphisms cannot be composed because their table row maps do not line up.

Fields

table: String

The table where composition fails.

detail: String

What is wrong.

Trait Implementations

impl Clone for HomError

fn clone(&self) -> HomError

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for HomError

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

Formats the value using the given formatter.

impl Display for HomError

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

Formats the value using the given formatter.

impl Eq for HomError

impl Error for HomError

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 HomError

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for HomError