Struct arithmetic_eval::Object

pub struct Object<T> { /* private fields */ }

Object with zero or more named fields.

An object functions similarly to a HashMap with String keys and Value values. It allows iteration over name-value pairs, random access by field name, inserting / removing fields etc.

Examples

let mut obj = Object::<u32>::default();
obj.insert("field", Value::Prim(0));
obj.insert("other_field", Value::Bool(false));
assert_eq!(obj.len(), 2);
assert_eq!(obj["field"].value_type(), ValueType::Prim);
assert!(obj.iter().all(|(_, val)| !val.is_void()));

// `Object` implements `FromIterator` / `Extend`.
let fields = vec![
    ("third", Value::Prim(3)),
    ("fourth", Value::native_fn(fns::Assert)),
];
let mut other_obj: Object<u32> = fields.into_iter().collect();
other_obj.extend(obj);
assert_eq!(other_obj.len(), 4);

Implementations

impl<T> Object<T>

pub fn just(field_name: impl Into<String>, value: Value<T>) -> Self

Creates an object with a single field.

pub fn len(&self) -> usize

Returns the number of fields in this object.

pub fn is_empty(&self) -> bool

Checks if this object is empty (has no fields).

pub fn iter(&self) -> impl Iterator<Item = (&str, &Value<T>)> + '_

Iterates over name-value pairs for all fields defined in this object.

pub fn field_names(&self) -> impl Iterator<Item = &str> + '_

Iterates over field names.

pub fn get(&self, field_name: &str) -> Option<&Value<T>>

Returns the value of a field with the specified name, or None if this object does not contain such a field.

pub fn contains_field(&self, field_name: &str) -> bool

Checks whether this object has a field with the specified name.

pub fn insert( &mut self, field_name: impl Into<String>, value: Value<T> ) -> Option<Value<T>>

Inserts a field into this object.

pub fn remove(&mut self, field_name: &str) -> Option<Value<T>>

Removes and returns the specified field from this object.

Trait Implementations

impl<T: Clone> Clone for Object<T>

fn clone(&self) -> Object<T>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T: Debug> Debug for Object<T>

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

Formats the value using the given formatter.

impl<T> Default for Object<T>

fn default() -> Self

Returns the “default value” for a type.

impl<T: Display> Display for Object<T>

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

Formats the value using the given formatter.

impl<T, S, V> Extend<(S, V)> for Object<T>where S: Into<String>, V: Into<Value<T>>,

fn extend<I: IntoIterator<Item = (S, V)>>(&mut self, iter: I)

Extends a collection with the contents of an iterator.

fn extend_one(&mut self, item: A)

🔬This is a nightly-only experimental API. (extend_one)

Extends a collection with exactly one element.

fn extend_reserve(&mut self, additional: usize)

🔬This is a nightly-only experimental API. (extend_one)

Reserves capacity in a collection for the given number of additional elements.

impl<T> From<Object<T>> for Value<T>

fn from(object: Object<T>) -> Self

Converts to this type from the input type.

impl<T, S, V> FromIterator<(S, V)> for Object<T>where S: Into<String>, V: Into<Value<T>>,

fn from_iter<I: IntoIterator<Item = (S, V)>>(iter: I) -> Self

Creates a value from an iterator.

impl<T> Index<&str> for Object<T>

type Output = Value<T>

The returned type after indexing.

fn index(&self, index: &str) -> &Self::Output

Performs the indexing (container[index]) operation.

impl<T> IntoEvalResult<T> for Object<T>

fn into_eval_result(self) -> Result<Value<T>, ErrorOutput>

Performs the conversion.

impl<'r, T> IntoIterator for &'r Object<T>

type IntoIter = Map<Iter<'r, String, Value<T>>, fn(_: (&'r String, &'r Value<T>)) -> (&'r str, &'r Value<T>)>

Iterator type should be considered an implementation detail.

type Item = (&'r str, &'r Value<T>)

The type of the elements being iterated over.

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl<T> IntoIterator for Object<T>

type IntoIter = IntoIter<String, Value<T>, Global>

Iterator type should be considered an implementation detail.

type Item = (String, Value<T>)

The type of the elements being iterated over.

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl<T: PartialEq> PartialEq<Object<T>> for Object<T>

fn eq(&self, other: &Object<T>) -> bool

This method tests for self and other values to be equal, and is used by ==.

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

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

impl<T> TryFromValue<T> for Object<T>

fn try_from_value(value: Value<T>) -> Result<Self, FromValueError>

Attempts to convert value to a type supported by the function.

impl<T> StructuralPartialEq for Object<T>