Enum jsondata::Json [−][src]
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 = 10.into();
let json: jsondata::Json = true.into();
let json: jsondata::Json = "hello world".into();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
Bool(bool)Tuple Fields of Bool
0: boolString(String)Tuple Fields of String
0: StringImplementations
Implementation provides methods to construct and validate Json values.
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.
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.
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.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.
Get a json field, within the document, locatable by path.
Set a json field, within the document, locatable by path.
Delete a JSON field, within the document, locatable by path.
Append a string or array to a JSON field within the document that is either a string or array.
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.
Implementation clones underlying type for each Json variant. The return value is always an Option because JSON follows a schema-less data representation.
Trait Implementations
This method returns an ordering between self and other values if one exists. Read more
This method tests less than (for self and other) and is used by the < operator. Read more
This method tests less than or equal to (for self and other) and is used by the <=
operator. Read more
This method tests greater than (for self and other) and is used by the > operator. Read more
Auto Trait Implementations
impl RefUnwindSafe for Json
impl UnwindSafe for Json
Blanket Implementations
Mutably borrows from an owned value. Read more