# [−] [src] Enum regex_syntax::ast::Ast

    pub enum Ast {
        Empty(Span),
        Flags(SetFlags),
        Literal(Literal),
        Dot(Span),
        Assertion(Assertion),
        Class(Class),
        Repetition(Repetition),
        Group(Group),
        Alternation(Alternation),
        Concat(Concat),
    }

An abstract syntax tree for a single regular expression.

An `Ast`'s `fmt::Display` implementation uses constant stack space and heap space proportional to the size of the `Ast`.

This type defines its own destructor that uses constant stack space and heap space proportional to the size of the `Ast`.

## Variants

`Empty(Span)`

An empty regex that matches everything.

`Flags(SetFlags)`

A set of flags, e.g., `(?is)`.

`Literal(Literal)`

A single character literal, which includes escape sequences.

`Dot(Span)`

The "any character" class.

`Assertion(Assertion)`

A single zero-width assertion.

`Class(Class)`

A single character class. This includes all forms of character classes except for `.`. e.g., `\d`, `\pN`, `[a-z]` and `[[:alpha:]]`.

`Repetition(Repetition)`

A repetition operator applied to an arbitrary regular expression.

`Group(Group)`

A grouped regular expression.

`Alternation(Alternation)`

An alternation of regular expressions.

`Concat(Concat)`

A concatenation of regular expressions.

## Methods

### `impl Ast` [src]

#### `pub fn span(&self) -> &Span` [src]

Return the span of this abstract syntax tree.

#### `pub fn is_empty(&self) -> bool` [src]

Return true if and only if this Ast is empty.

## Trait Implementations

### `impl PartialEq<Ast> for Ast` [src]

#### `fn eq(&self, other: &Ast) -> bool` [src]

This method tests for `self` and `other` values to be equal, and is used by `==`. Read more

#### `fn ne(&self, other: &Ast) -> bool` [src]

This method tests for `!=`.

### `impl Clone for Ast` [src]

#### `fn clone(&self) -> Ast` [src]

Returns a copy of the value. Read more

#### `fn clone_from(&mut self, source: &Self)`1.0.0 [src]

Performs copy-assignment from `source`. Read more

### `impl Eq for Ast` [src]

### `impl Drop for Ast` [src]

A custom `Drop` impl is used for `Ast` such that it uses constant stack space but heap space proportional to the depth of the `Ast`.

#### `fn drop(&mut self)` [src]

Executes the destructor for this type. Read more

### `impl Display for Ast` [src]

Print a display representation of this Ast.

This does not preserve any of the original whitespace formatting that may have originally been present in the concrete syntax from which this Ast was generated.

This implementation uses constant stack space and heap space proportional to the size of the `Ast`.

#### `fn fmt(&self, f: &mut Formatter) -> Result` [src]

Formats the value using the given formatter. Read more

### `impl Debug for Ast` [src]

#### `fn fmt(&self, f: &mut Formatter) -> Result` [src]

Formats the value using the given formatter. Read more

## Auto Trait Implementations

### `impl Send for Ast`

### `impl Sync for Ast`

## Blanket Implementations

### `impl<T> From<T> for T` [src]

#### `fn from(t: T) -> T` [src]

Performs the conversion.

### `impl<T> ToOwned for T where
T: Clone,` [src]

#### `type Owned = T`

The resulting type after obtaining ownership.

#### `fn to_owned(&self) -> T` [src]

Creates owned data from borrowed data, usually by cloning. Read more

#### `fn clone_into(&self, target: &mut T)` [src]

🔬 This is a nightly-only experimental API. (`toowned_clone_into`)

recently added

Uses borrowed data to replace owned data, usually by cloning. Read more

### `impl<T> ToString for T where
T: Display + ?Sized,` [src]

#### `default fn to_string(&self) -> String` [src]

Converts the given value to a `String`. Read more

### `impl<T, U> Into<U> for T where
U: From<T>,` [src]

#### `fn into(self) -> U` [src]

Performs the conversion.

### `impl<T, U> TryFrom<U> for T where
U: Into<T>,` [src]

#### `type Error = Infallible`

The type returned in the event of a conversion error.

#### `fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>` [src]

Performs the conversion.

### `impl<T, U> TryInto<U> for T where
U: TryFrom<T>,` [src]

#### `type Error = <U as TryFrom<T>>::Error`

The type returned in the event of a conversion error.

#### `fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>` [src]

Performs the conversion.

### `impl<T> BorrowMut<T> for T where
T: ?Sized,` [src]

#### `fn borrow_mut(&mut self) -> &mut T` [src]

Mutably borrows from an owned value. Read more

### `impl<T> Borrow<T> for T where
T: ?Sized,` [src]

#### `fn borrow(&self) -> &T` [src]

Immutably borrows from an owned value. Read more

### `impl<T> Any for T where
T: 'static + ?Sized,` [src]

#### `fn type_id(&self) -> TypeId` [src]

Gets the `TypeId` of `self`. Read more

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