pub enum Json {
Null,
Bool(bool),
Integer(Integral),
Float(Floating),
String(String),
Array(Vec<Json>),
Object(Vec<Property>),
// some variants omitted
}Expand description
Json type implements JavaScript Object Notation as per specification RFC-8259.
- JSON scalar types - Null, Number, Boolean, String, are supported.
- JSON container types - Array, Object, are supported.
- JSON numbers can be 128-bit integers or 64-bit floating point.
- When document is known to contain lot of numbers and only one of
them needs to be extracted, parsing the entire document can be
inefficient just to get that one field. Numbers are implemented
with deferred conversion, using
IntegralandFloatingtypes. - Arrays are implemented as vector of Json values Vec<Json>.
- Objects are implemented as vector of properties, Vec<Property>, where each property is a tuple of (key, value). Here key is String type and value is Json type.
Json enum type has documented variants and undocumented variants. Applications, when matching with Json, must use the catch-all variant:
match json {
Json::Null => // handle null,
Json::Bool(b) => // handle bool,
Json::Integer(i) => // handle integer,
Json::Float(f) => // handle float,
Json::String(s) => // handle string,
Json::Array(a) => // handle array,
Json::Object(o) => // handle object,
_ => // catch all.
}Parsing JSON text:
let json: jsondata::Json = "10".parse().unwrap();return a Json enum type.
Converting Rust native types to Json enum:
Json supports conversion from bool, u8, i8, u16, i16, u32,
i32, u64, i64, i128, i128, f32, f64, String, str,
Vec<Json> and Vec<Property> types using the From trait.
Converting from u128 shall cause panic if value is larger than
i128::max().
let json = jsondata::Json::from(10);
let json = jsondata::Json::from(true);
let json = jsondata::Json::from("hello world");On the other direction, Json enum can be converted to Rust native types using accessor methods,
- is_null() to check whether Json is Null
- to_bool(), to_integer(), to_float(), to_string() methods return the
underlying value as Option<
T> whereTis bool or i128 or f64 or String. - to_array(), return JSON array as Vec<Json>.
- to_object(), return JSON object as Vec<Property>.
- Refer to API list and conversion traits implementation for more details.
Some of the properties implemented for Json are:
- Json implements total ordering.
- Default value for Json is Null.
- Json types are clone-able but do not implement Copy.
- Json value can be serialized into JSON format using Display trait.
Panics
Json implements AsRef and AsMut traits for str, Vec<Json>, Vec<Property> types. This means, call to as_ref() and as_mut() shall panic when underlying Json variant do not match with expected type.
Variants
Null
Bool(bool)
Integer(Integral)
Float(Floating)
String(String)
Array(Vec<Json>)
Object(Vec<Property>)
Implementations
sourceimpl Json
impl Json
Implementation provides methods to construct and validate Json values.
sourcepub fn new<T>(value: T) -> Jsonwhere
Self: From<T>,
pub fn new<T>(value: T) -> Jsonwhere
Self: From<T>,
Construct Json from bool, i128, f64, String, str, Vec.
Array can be composed as:
use jsondata::Json;
let mut js = Json::new::<Vec<Json>>(Vec::new());
js.append("", Json::new(10));
js.append("", Json::new("hello world".to_string()));It is also possible to construct the vector of Json outside the append() method, and finally use Json::new() to construct the array.
Object can be composed as:
use jsondata::{Json, Property};
let mut js = Json::new::<Vec<Property>>(Vec::new());
js.set("/key1", Json::new(10));
js.set("/key2", Json::new(true));It is also possible to construct the vector of properties outside the set() method, and finally use Json::new() to construct the object.
sourcepub fn validate(&mut self) -> Result<()>
pub fn validate(&mut self) -> Result<()>
Validate parts of JSON text that are not yet parsed. Typically, when used in database context, JSON documents are validated once but parsed multiple times.
sourcepub fn compute(&mut self) -> Result<()>
pub fn compute(&mut self) -> Result<()>
Compute parses unparsed text and convert them into numbers. When a JSON document is parsed once but operated on multiple times it is better to call compute for better performance.
use jsondata::Json;
let text = r#"[null,true,false,10,"true"]"#;
let mut json: Json = text.parse().unwrap();
json.compute();
// perform lookup and arithmetic operations on parsed document.pub fn type_name(&self) -> String
sourceimpl Json
impl Json
Implementation provides CRUD access into Json document using Json Pointer. For all methods,
- Path must be valid JSON Pointer.
- Path fragment must be valid key if parent container is an object.
- Path fragment must be a number index if parent container is an array.
sourcepub fn get(&self, path: &str) -> Result<Json>
pub fn get(&self, path: &str) -> Result<Json>
Get a json field, within the document, locatable by path.
sourcepub fn set(&mut self, path: &str, value: Json) -> Result<()>
pub fn set(&mut self, path: &str, value: Json) -> Result<()>
Set a json field, within the document, locatable by path.
sourcepub fn delete(&mut self, path: &str) -> Result<()>
pub fn delete(&mut self, path: &str) -> Result<()>
Delete a JSON field, within the document, locatable by path.
sourcepub fn append(&mut self, path: &str, value: Json) -> Result<()>
pub fn append(&mut self, path: &str, value: Json) -> Result<()>
Append a string or array to a JSON field within the document that is either a string or array.
sourcepub fn range<R>(&self, range: R) -> Jsonwhere
R: RangeBounds<isize>,
pub fn range<R>(&self, range: R) -> Jsonwhere
R: RangeBounds<isize>,
Range operation on Json array,
- Range
[start..end]. - RangeFrom
[start..]. - RangeFull
[..]. - RangeInclusive
[start..=end]. - RangeTo
[..end]. - RangeToInclusive
[..=end].
If range is called on non array Json, returns a Json Error.
sourceimpl Json
impl Json
Implementation clones underlying type for each Json variant. The return value is always an Option because JSON follows a schema-less data representation.
pub fn is_null(&self) -> bool
pub fn to_bool(&self) -> Option<bool>
pub fn to_integer(&self) -> Option<i128>
pub fn to_float(&self) -> Option<f64>
pub fn as_str(&self) -> Option<&str>
pub fn to_array(&self) -> Option<Vec<Json>>
pub fn to_object(&self) -> Option<Vec<Property>>
pub fn is_error(&self) -> bool
pub fn to_error(&self) -> Option<Error>
pub fn to_result(&self) -> Result<&Json>
Trait Implementations
sourceimpl Ord for Json
impl Ord for Json
1.21.0 · sourceconst fn max(self, other: Self) -> Self
const fn max(self, other: Self) -> Self
1.21.0 · sourceconst fn min(self, other: Self) -> Self
const fn min(self, other: Self) -> Self
1.50.0 · sourceconst fn clamp(self, min: Self, max: Self) -> Selfwhere
Self: PartialOrd<Self>,
const fn clamp(self, min: Self, max: Self) -> Selfwhere
Self: PartialOrd<Self>,
sourceimpl PartialOrd<Json> for Json
impl PartialOrd<Json> for Json
sourcefn partial_cmp(&self, other: &Json) -> Option<Ordering>
fn partial_cmp(&self, other: &Json) -> Option<Ordering>
1.0.0 · sourceconst fn le(&self, other: &Rhs) -> bool
const fn le(&self, other: &Rhs) -> bool
self and other) and is used by the <=
operator. Read more