Struct VariableRegistry

pub struct VariableRegistry { /* private fields */ }

Compile-time variable registry.

VariableRegistry manages variable declarations and constant definitions during the CEL environment compilation phase. It maintains a mapping from variable names to variable entries, where each entry can be either:

• A constant value (Constant): A fixed value known at compile time
• A variable declaration: A type declaration with value provided at runtime

Examples

use cel_cxx::{ValueType, VariableRegistry};

let mut registry = VariableRegistry::new();

// Define constants
registry.define_constant("PI", 3.14159)?;
registry.define_constant("APP_NAME", "MyApp")?;

// Declare variables
registry.declare::<String>("user_input")?;

assert_eq!(registry.len(), 3);

Implementations

impl VariableRegistry

pub fn new() -> Self

Creates a new empty variable registry.

Returns

A new empty VariableRegistry

pub fn define_constant<T>( &mut self, name: impl Into<String>, value: T, ) -> Result<&mut Self, Error>

where T: IntoConstant,

Defines a constant value.

Constants are values that are known at compile time and don’t change during evaluation. They can be used directly in CEL expressions without requiring runtime bindings.

Type Parameters

• T: The constant type, must implement IntoConstant

Parameters

• name: The constant name
• value: The constant value

Returns

Returns &mut Self to support method chaining, or Error if an error occurs

Examples

use cel_cxx::VariableRegistry;

let mut registry = VariableRegistry::new();
registry
    .define_constant("PI", 3.14159)?
    .define_constant("APP_NAME", "MyApp")?
    .define_constant("MAX_USERS", 1000i64)?;

pub fn declare<T>( &mut self, name: impl Into<String>, ) -> Result<&mut Self, Error>

where T: TypedValue,

Declares a variable with a specific type.

Variable declarations only specify the type, with actual values provided at runtime through Activation. The type is determined by the generic parameter T which must implement TypedValue.

Type Parameters

• T: The variable type, must implement TypedValue

Parameters

• name: The variable name

Returns

Returns &mut Self to support method chaining, or Error if an error occurs

Examples

use cel_cxx::VariableRegistry;

let mut registry = VariableRegistry::new();
registry
    .declare::<String>("user_name")?
    .declare::<i64>("user_id")?
    .declare::<bool>("is_admin")?;

pub fn entries( &self, ) -> impl Iterator<Item = (&String, &VariableDeclOrConstant)>

Returns an iterator over all variable entries.

The iterator yields (name, entry) pairs for all registered variables and constants.

Returns

Iterator yielding (&String, &VariableDeclOrConstant) pairs

pub fn entries_mut( &mut self, ) -> impl Iterator<Item = (&String, &mut VariableDeclOrConstant)>

Returns a mutable iterator over all variable entries.

The iterator yields (name, entry) pairs and allows modifying the entries.

Returns

Iterator yielding (&String, &mut VariableDeclOrConstant) pairs

pub fn find(&self, name: &str) -> Option<&VariableDeclOrConstant>

Finds a variable entry by name.

Parameters

• name: The variable name to search for

Returns

Returns Some(&VariableDeclOrConstant) if found, None otherwise

pub fn find_mut(&mut self, name: &str) -> Option<&mut VariableDeclOrConstant>

Finds a mutable variable entry by name.

Parameters

• name: The variable name to search for

Returns

Returns Some(&mut VariableDeclOrConstant) if found, None otherwise

pub fn remove(&mut self, name: &str) -> Option<VariableDeclOrConstant>

Removes a variable entry by name.

Parameters

• name: The variable name to remove

Returns

Returns Some(VariableDeclOrConstant) if the entry was found and removed, None otherwise

pub fn clear(&mut self)

Clears all variable entries.

pub fn len(&self) -> usize

Returns the number of variable entries.

Returns

Number of registered variables and constants

pub fn is_empty(&self) -> bool

Returns whether the registry is empty.

Returns

true if no variables or constants are registered, false otherwise

Trait Implementations

impl Debug for VariableRegistry

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

Formats the value using the given formatter.

impl Default for VariableRegistry

fn default() -> VariableRegistry

Returns the “default value” for a type.