Enum Expr 

pub enum Expr {
    Empty,
    Concat(Vec<Expr>),
    Alt(Vec<Expr>),
    Quant(Box<Expr>, u32, Option<u32>),
    Class(ClassSet),
    Anchor(AnchorKind),
}

Parsed XSD regex. Classes are flattened to [ClassSet] at parse time so the NFA builder doesn’t need to know about \p{...}, \d, class subtraction, etc.

Variants

Empty

Matches the empty string.

Concat(Vec<Expr>)

Concatenation of subexpressions, evaluated left-to-right.

Alt(Vec<Expr>)

Alternation — match any one branch. XSD §F has no preference between branches (no backtracking semantics to preserve), but the NFA emits them in source order.

Quant(Box<Expr>, u32, Option<u32>)

Counted repetition. max == None means unbounded.

Class(ClassSet)

Single-codepoint match against a character class. Literal chars and . lower to single-range / universe classes.

Anchor(AnchorKind)

Position anchor (XPath 2.0 only; XSD §F has none). Matches the empty string when the simulator is at the asserted position. The m-flag (multiline) variants assert on line boundaries; without m they assert on input boundaries.

Trait Implementations

impl Clone for Expr

fn clone(&self) -> Expr

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Expr

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

Formats the value using the given formatter.