Enum Value 

pub enum Value {
    Null,
    Bool(bool),
    Int(i64),
    Float(f64),
    Str(String),
    Bytes(Vec<u8>),
    Array(Vec<Value>),
    Object(Document),
}

A single field value inside a Document.

Value is deliberately small and closed: it models the shapes a schemaless document store needs and nothing more. Nesting is expressed through Value::Array and Value::Object, so an arbitrarily deep record is just a tree of Values.

Examples

use bison_db::Value;

let v = Value::from("hello");
assert_eq!(v.as_str(), Some("hello"));
assert!(Value::from(42_i64).as_int() == Some(42));
assert!(Value::Null.is_null());

Variants

Null

The absence of a value.

Bool(bool)

A boolean.

Int(i64)

A signed 64-bit integer. All integral fields are stored at this width.

Float(f64)

A 64-bit IEEE-754 float.

Str(String)

A UTF-8 string.

Bytes(Vec<u8>)

An opaque byte string, for binary fields that are not valid UTF-8.

Array(Vec<Value>)

An ordered list of values.

Object(Document)

A nested document.

Implementations

impl Value

pub const fn is_null(&self) -> bool

Returns true if this value is Value::Null.

Examples

use bison_db::Value;
assert!(Value::Null.is_null());
assert!(!Value::from(0_i64).is_null());

pub const fn as_bool(&self) -> Option<bool>

Returns the boolean if this is a Value::Bool, otherwise None.

Examples

use bison_db::Value;
assert_eq!(Value::from(true).as_bool(), Some(true));
assert_eq!(Value::from(1_i64).as_bool(), None);

pub const fn as_int(&self) -> Option<i64>

Returns the integer if this is a Value::Int, otherwise None.

Floats are not coerced; a Value::Float returns None.

Examples

use bison_db::Value;
assert_eq!(Value::from(7_i64).as_int(), Some(7));
assert_eq!(Value::from(7.0_f64).as_int(), None);

pub const fn as_float(&self) -> Option<f64>

Returns the float if this is a Value::Float, otherwise None.

Examples

use bison_db::Value;
assert_eq!(Value::from(1.5_f64).as_float(), Some(1.5));
assert_eq!(Value::from(1_i64).as_float(), None);

pub fn as_str(&self) -> Option<&str>

Returns the string slice if this is a Value::Str, otherwise None.

Examples

use bison_db::Value;
assert_eq!(Value::from("bison").as_str(), Some("bison"));

pub fn as_bytes(&self) -> Option<&[u8]>

Returns the byte slice if this is a Value::Bytes, otherwise None.

Examples

use bison_db::Value;
assert_eq!(Value::Bytes(vec![1, 2, 3]).as_bytes(), Some(&[1, 2, 3][..]));

pub fn as_array(&self) -> Option<&[Value]>

Returns the element slice if this is a Value::Array, otherwise None.

Examples

use bison_db::Value;
let v = Value::Array(vec![Value::from(1_i64), Value::from(2_i64)]);
assert_eq!(v.as_array().map(<[_]>::len), Some(2));

pub fn as_object(&self) -> Option<&Document>

Returns the nested document if this is a Value::Object, otherwise None.

Examples

use bison_db::{Document, Value};
let mut inner = Document::new();
inner.set("k", 1_i64);
let v = Value::Object(inner);
assert_eq!(v.as_object().and_then(|d| d.get("k")).and_then(Value::as_int), Some(1));

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

Returns a short, stable name for the value’s variant.

Intended for diagnostics and error messages, not for logic; match on the variant directly when behaviour depends on the type.

Examples

use bison_db::Value;
assert_eq!(Value::from(1_i64).type_name(), "int");
assert_eq!(Value::Null.type_name(), "null");

Trait Implementations

impl Clone for Value

fn clone(&self) -> Value

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Value

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

Formats the value using the given formatter.

impl Default for Value

fn default() -> Value

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for Value

Available on crate feature serde only.

fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error>

Deserialize this value from the given Serde deserializer.

impl From<&str> for Value

fn from(v: &str) -> Self

Converts to this type from the input type.

impl From<Document> for Value

fn from(v: Document) -> Self

Converts to this type from the input type.

impl<T: Into<Value>> From<Option<T>> for Value

fn from(v: Option<T>) -> Self

Some(x) becomes x’s value; None becomes Value::Null.

impl From<String> for Value

fn from(v: String) -> Self

Converts to this type from the input type.

impl From<Vec<Value>> for Value

fn from(v: Vec<Value>) -> Self

Converts to this type from the input type.

impl From<Vec<u8>> for Value

fn from(v: Vec<u8>) -> Self

Converts to this type from the input type.

impl From<bool> for Value

fn from(v: bool) -> Self

Converts to this type from the input type.

impl From<f64> for Value

fn from(v: f64) -> Self

Converts to this type from the input type.

impl From<i32> for Value

fn from(v: i32) -> Self

Converts to this type from the input type.

impl From<i64> for Value

fn from(v: i64) -> Self

Converts to this type from the input type.

impl From<u32> for Value

fn from(v: u32) -> Self

Converts to this type from the input type.

impl PartialEq for Value

fn eq(&self, other: &Value) -> 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 Serialize for Value

Available on crate feature serde only.

fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error>

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for Value