Struct MaybeItem 

pub struct MaybeItem<'de> { /* private fields */ }

A nullable reference to a parsed TOML value.

MaybeItem is returned by the index operators ([]) on Item, Table, Array, and MaybeItem itself. It acts like an Option<&Item> that can be further indexed without panicking. Chained lookups on missing keys simply propagate the None state.

Use the as_* accessors to extract a value, or call item to get back an Option<&Item>.

Examples

use toml_spanner::Arena;

let arena = Arena::new();
let table = toml_spanner::parse(r#"
[server]
host = "localhost"
port = 8080
"#, &arena).unwrap();

// Successful nested lookup.
assert_eq!(table["server"]["host"].as_str(), Some("localhost"));
assert_eq!(table["server"]["port"].as_i64(), Some(8080));

// Missing keys propagate through chained indexing without panicking.
assert_eq!(table["server"]["missing"].as_str(), None);
assert_eq!(table["nonexistent"]["deep"]["path"].as_str(), None);

// Convert back to an Option<&Item> when needed.
assert!(table["server"]["host"].item().is_some());
assert!(table["nope"].item().is_none());

Implementations

impl<'de> MaybeItem<'de>

pub fn from_ref<'a>(item: &'a Item<'de>) -> &'a Self

Views an Item reference as a MaybeItem.

pub fn item(&self) -> Option<&Item<'de>>

Returns the underlying Item, or None if this is a missing value.

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

Returns a borrowed string if this is a string value.

pub fn as_i128(&self) -> Option<i128>

Returns an i128 if this is an integer value.

pub fn as_i64(&self) -> Option<i64>

Returns an i64 if this is an integer value that fits in the i64 range.

pub fn as_u64(&self) -> Option<u64>

Returns a u64 if this is an integer value that fits in the u64 range.

pub fn as_f64(&self) -> Option<f64>

Returns an f64 if this is a float or integer value.

Integer values are converted to f64 via as cast (lossy for large values outside the 2^53 exact-integer range).

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

Returns a bool if this is a boolean value.

pub fn as_array(&self) -> Option<&Array<'de>>

Returns a borrowed array if this is an array value.

pub fn as_table(&self) -> Option<&Table<'de>>

Returns a borrowed table if this is a table value.

pub fn as_datetime(&self) -> Option<&DateTime>

Returns a borrowed DateTime if this is a datetime value.

pub fn span(&self) -> Span

Returns the source span, or 0..0 if this is a missing value.

pub fn value(&self) -> Option<Value<'_, 'de>>

Returns a borrowed Value for pattern matching, or None if missing.

Trait Implementations

impl Debug for MaybeItem<'_>

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

Formats the value using the given formatter.

impl<'de> Index<&str> for MaybeItem<'de>

type Output = MaybeItem<'de>

The returned type after indexing.

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

Performs the indexing (container[index]) operation.

impl<'de> Index<usize> for MaybeItem<'de>

type Output = MaybeItem<'de>

The returned type after indexing.

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

Performs the indexing (container[index]) operation.

impl Send for MaybeItem<'_>

impl Sync for MaybeItem<'_>