Struct ParamsSequence 

pub struct ParamsSequence<'a>(/* private fields */);

An Iterator-like parser for a sequence of Params.

This will parse the params one at a time, and allows for graceful handling of optional parameters at the tail; other use cases are likely better served by Params::parse. The reason this is not an actual Iterator is that params parsing (often) yields values of different types.

Regards empty array [] as no parameters provided.

Implementations

impl<'a> ParamsSequence<'a>

pub fn next<T>(&mut self) -> Result<T, ErrorObjectOwned>

where T: Deserialize<'a>,

Parse the next parameter to type T

let params = Params::new(Some(r#"[true, 10, "foo"]"#));
let mut seq = params.sequence();

let a: bool = seq.next().unwrap();
let b: i32 = seq.next().unwrap();
let c: &str = seq.next().unwrap();

assert_eq!(a, true);
assert_eq!(b, 10);
assert_eq!(c, "foo");

pub fn optional_next<T>(&mut self) -> Result<Option<T>, ErrorObjectOwned>

where T: Deserialize<'a>,

Parse the next optional parameter to type Option<T>.

The result will be None for null, and for missing values in the supplied JSON array.

let params = Params::new(Some(r#"[1, 2, null]"#));
let mut seq = params.sequence();

let params: [Option<u32>; 4] = [
    seq.optional_next().unwrap(),
    seq.optional_next().unwrap(),
    seq.optional_next().unwrap(),
    seq.optional_next().unwrap(),
];

assert_eq!(params, [Some(1), Some(2), None, None]);

Trait Implementations

impl<'a> Clone for ParamsSequence<'a>

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<'a> Copy for ParamsSequence<'a>

impl<'a> Debug for ParamsSequence<'a>

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

Formats the value using the given formatter.

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 16 bytes