Struct evalexpr::HashMapContext

pub struct HashMapContext { /* private fields */ }

A context that stores its mappings in hash maps.

Value and function mappings are stored independently, meaning that there can be a function and a value with the same identifier.

This context is type-safe, meaning that an identifier that is assigned a value of some type once cannot be assigned a value of another type.

Implementations

impl HashMapContext

pub fn new() -> Self

Constructs a HashMapContext with no mappings.

Trait Implementations

impl Clone for HashMapContext

fn clone(&self) -> HashMapContext

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Context for HashMapContext

fn get_value(&self, identifier: &str) -> Option<&Value>

Returns the value that is linked to the given identifier.

fn call_function( &self, identifier: &str, argument: &Value ) -> EvalexprResult<Value>

Calls the function that is linked to the given identifier with the given argument. If no function with the given identifier is found, this method returns EvalexprError::FunctionIdentifierNotFound.

fn are_builtin_functions_disabled(&self) -> bool

Checks if builtin functions are disabled.

fn set_builtin_functions_disabled( &mut self, disabled: bool ) -> EvalexprResult<()>

Disables builtin functions if disabled is true, and enables them otherwise. If the context does not support enabling or disabling builtin functions, an error is returned.

impl ContextWithMutableFunctions for HashMapContext

fn set_function( &mut self, identifier: String, function: Function ) -> EvalexprResult<()>

Sets the function with the given identifier to the given function.

impl ContextWithMutableVariables for HashMapContext

fn set_value(&mut self, identifier: String, value: Value) -> EvalexprResult<()>

Sets the variable with the given identifier to the given value.

impl Debug for HashMapContext

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

Formats the value using the given formatter.

impl Default for HashMapContext

fn default() -> HashMapContext

Returns the “default value” for a type.

impl IterateVariablesContext for HashMapContext

type VariableIterator<'a> = Map<Iter<'a, String, Value>, fn(_: (&String, &Value)) -> (String, Value)>

The iterator type for iterating over variable name-value pairs.

type VariableNameIterator<'a> = Cloned<Keys<'a, String, Value>>

The iterator type for iterating over variable names.

fn iter_variables(&self) -> Self::VariableIterator<'_>

Returns an iterator over pairs of variable names and values.

fn iter_variable_names(&self) -> Self::VariableNameIterator<'_>

Returns an iterator over variable names.