Struct Span

Source

pub struct Span {
    pub start: u32,
    pub end: u32,
}

Expand description

A half-open byte range [start, end) into some source string.

Fields§

§start: u32§end: u32

Implementations§

Source §

pub const fn len(self) -> u32

Byte-width of the half-open range [start, end). pub const fn — u32::saturating_sub is const-stable since Rust 1.47, well before this workspace’s 1.89 MSRV floor, so the promotion is a body- preserving type-signature widening. Matches the sibling Self::new / Self::point / Self::contains / Self::union pub const fn shape on the same Span primitive — every downstream consumer that wants a compile-time span-width fixture (a const WIDTH: u32 = SPAN.len(); LSP hover-registry entry, a per-diagnostic const-context width oracle a future admission webhook consults, a compile-time span-partition truth table the caixa-fmt trivia-owner resolver keys off) now reads through one substrate-primitive const dispatch rather than being forced onto the runtime code path.

Source

pub const fn is_empty(self) -> bool

Half-open emptiness predicate — true iff self.start == self.end. pub const fn — folds onto the sibling Self::len pub const fn promotion (integer equality is const in Rust since long before this workspace’s 1.89 MSRV floor). Matches every other accessor / predicate on this Span primitive’s const-eval surface; only the fundamentally-runtime-only slice(&str) method (string-slice indexing outside const-eval) remains pub fn.

Source

pub const fn union(self, other: Span) -> Span

The smallest span covering both. Useful for building a list node’s span from its children — every parser code path that composes a parent span from its immediate child boundaries reads through this (open.union(close) on a delimited list, head.union(target.span) on a quote-form target, and every downstream trivia-owner / diagnostic-aggregator / fmt-region parent-span builder). pub const fn — the body reaches for u32::min / u32::max, both const stable since Rust 1.83 (well before this workspace’s 1.89 MSRV floor), so the promotion is a body-preserving type-signature widening. Matches the sibling Self::new / Self::point / Self::contains pub const fn shape on the same Span primitive — every downstream consumer that wants a compile-time span-composition fixture (a const OUTER: Span = INNER1.union( INNER2); LSP hover-registry entry, a per-diagnostic const-context parent-span oracle a future admission webhook consults, a compile-time span-partition truth table the caixa-fmt trivia-owner resolver keys off) now reads through one substrate-primitive const dispatch rather than being forced onto the runtime code path.

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pub fn slice<'a>(self, src: &'a str) -> &'a str

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pub const fn contains(self, offset: u32) -> bool

Byte-offset half-open containment predicate every consumer that keys off an author-authored source position (LSP hover span-lookup at the cursor, per-diagnostic span-registry probe, per-trivia leading/trailing-owner attachment gate) reads through — returns true iff offset lies inside the half-open range [self.start, self.end). pub const fn — matches the sibling Self::new / Self::point pub const fn shape on the same Span primitive’s construction axis, extending the const-eval surface onto the primitive’s containment-predicate axis without a body change (integer comparison is const in Rust since long before this workspace’s 1.89 MSRV floor). Every downstream consumer that wants a compile-time span-containment fixture — a const IS_INSIDE: bool = SPAN.contains(OFFSET); LSP hover- registry entry, a per-diagnostic const-context span oracle a future admission webhook consults, a compile-time span-partition truth table the caixa-fmt trivia-owner resolver keys off — now reads through one substrate-primitive const dispatch rather than being forced onto the runtime code path.