pub enum HirKind {
Empty,
Literal(Literal),
Class(Class),
Look(Look),
Repetition(Repetition),
Capture(Capture),
Concat(Vec<Hir>),
Alternation(Vec<Hir>),
}Expand description
The underlying kind of an arbitrary Hir expression.
An HirKind is principally useful for doing case analysis on the type
of a regular expression. If you’re looking to build new Hir values,
then you must use the smart constructors defined on Hir, like
Hir::repetition, to build new Hir values. The API intentionally does
not expose any way of building an Hir directly from an HirKind.
Variants§
Empty
The empty regular expression, which matches everything, including the empty string.
Literal(Literal)
A literal string that matches exactly these bytes.
Class(Class)
A single character class that matches any of the characters in the class. A class can either consist of Unicode scalar values as characters, or it can use bytes.
A class may be empty. In which case, it matches nothing.
Look(Look)
A look-around assertion. A look-around match always has zero length.
Repetition(Repetition)
A repetition operation applied to a sub-expression.
Capture(Capture)
A capturing group, which contains a sub-expression.
Concat(Vec<Hir>)
A concatenation of expressions.
A concatenation matches only if each of its sub-expressions match one after the other.
Concatenations are guaranteed by Hir’s smart constructors to always
have at least two sub-expressions.
Alternation(Vec<Hir>)
An alternation of expressions.
An alternation matches only if at least one of its sub-expressions match. If multiple sub-expressions match, then the leftmost is preferred.
Alternations are guaranteed by Hir’s smart constructors to always
have at least two sub-expressions.