Enum Invocation 

pub enum Invocation {
    Member(String),
    Function(String, Vec<Expression>),
    This,
    Index,
    Total,
}

Represents an invocation in a FHIRPath expression

An invocation represents different ways to reference or call something in FHIRPath. This includes member access, function calls, and special contextual identifiers like $this, $index, and $total.

Invocations are fundamental building blocks in FHIRPath expressions and are used for navigation, function application, and context references.

Variants

Member(String)

A member access, referencing a property by name (e.g., Patient.name, Observation.value)

Function(String, Vec<Expression>)

A function call with optional arguments (e.g., first(), where(value > 5), substring(2, 5))

This

A reference to the current focus item ($this) Used in expressions like $this.name or in lambda expressions

Index

A reference to the current index ($index) Used in expressions like $index > 5 in filtering operations

Total

A reference to the current aggregate total ($total) Used in the aggregate() function to access the running total

Trait Implementations

impl Clone for Invocation

fn clone(&self) -> Invocation

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Invocation

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

Formats the value using the given formatter.

impl PartialEq for Invocation

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for Invocation