Struct ElementRef 

pub struct ElementRef { /* private fields */ }

Reference to a data element within a segment definition.

Fields are private to enforce the one-based position invariant through the ElementRef::new constructor. Use ElementRef::new for a simple data element and ElementRef::composite for a composite whose components are themselves named (panics at compile time when position == 0).

Use OwnedElementRef for runtime-constructed element refs.

Implementations

impl ElementRef

pub const fn new( position: u8, data_element: &'static str, status: Status, max_repeat: u8, ) -> Self

Construct an ElementRef for a simple data element.

position must be ≥ 1 (one-based). When called in a const context (e.g. inside a static array initialiser), a zero position causes a compile-time error. At runtime it panics.

Use composite when the element is a composite whose components carry their own UN/EDIFACT identifiers.

Panics

Panics if position == 0.

Example

use edifact_rs::{ElementRef, Status};

const BGM_1001: ElementRef = ElementRef::new(1, "1001", Status::Mandatory, 1);

pub const fn composite( position: u8, data_element: &'static str, status: Status, max_repeat: u8, components: &'static [ComponentRef], ) -> Self

Construct an ElementRef for a composite data element with named components.

Declaring components is what lets code-addressed access reach inside a composite: value_by_code(&DTM, "2380") resolves to element 1, component 2 without the caller counting positions. Declared components also make the mandatory-component check in DirectoryValidator active for this element.

Panics

Panics if position == 0.

Example

use edifact_rs::{ComponentRef, ElementRef, Status};

static C507: &[ComponentRef] = &[
    ComponentRef::new(1, "2005", Status::Mandatory),
    ComponentRef::new(2, "2380", Status::Conditional),
    ComponentRef::new(3, "2379", Status::Conditional),
];
const DTM_C507: ElementRef =
    ElementRef::composite(1, "C507", Status::Mandatory, 1, C507);

pub const fn position(&self) -> u8

One-based element position in the segment definition.

pub const fn data_element(&self) -> &'static str

UN/EDIFACT data element identifier.

pub const fn status(&self) -> Status

Requirement status of the element.

pub const fn max_repeat(&self) -> u8

Maximum repetition count for this element.

pub const fn components(&self) -> &'static [ComponentRef]

Component definitions; empty when this is a simple data element.

pub const fn with_repr(self, repr: Repr) -> Self

Attach the directory’s representation for a simple data element.

A composite carries its representations on the components instead, so this is ignored when components is non-empty.

pub const fn repr(&self) -> Option<Repr>

The declared representation, if the definition states one.

pub const fn with_repr_by_syntax_version( self, up_to_v3: Repr, from_v4: Repr, ) -> Self

Declare a representation that changed between syntax versions.

The service directory has exactly one such position: S004 DE 0017, the date of preparation. Version 3 transfers YYMMDD (n6); version 4 widened it to CCYYMMDD (n8) to be year-2000 correct. It is the only place where version 4 is not a superset of version 3.

Declaring both keeps each version checked exactly. Collapsing them into n..8 would have accepted a six-digit date in a version 4 interchange and a seven-digit one in either — validating neither version correctly.

The syntax version comes from UNB S001 DE 0002. When it cannot be determined — validating a bare message window, say — both are accepted, because guessing would reject conformant data.

pub const fn repr_from_v4(&self) -> Option<Repr>

The representation used from syntax version 4 onward, when it differs.

Trait Implementations

impl Clone for ElementRef

fn clone(&self) -> ElementRef

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for ElementRef

impl Debug for ElementRef

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

Formats the value using the given formatter.