pub enum Pattern {
    Var {
        var: Ident,
        pos: Pos,
    },
    BindPattern {
        var: Ident,
        subpat: Box<Pattern>,
        pos: Pos,
    },
    ConstInt {
        val: i128,
        pos: Pos,
    },
    ConstPrim {
        val: Ident,
        pos: Pos,
    },
    Term {
        sym: Ident,
        args: Vec<Pattern>,
        pos: Pos,
    },
    Wildcard {
        pos: Pos,
    },
    And {
        subpats: Vec<Pattern>,
        pos: Pos,
    },
    MacroArg {
        index: usize,
        pos: Pos,
    },
}
Expand description

A pattern: the left-hand side of a rule.

Variants§

§

Var

Fields

§var: Ident
§pos: Pos

A mention of a variable.

Equivalent either to a binding (which can be emulated with BindPattern with a Pattern::Wildcard subpattern), if this is the first mention of the variable, in order to capture its value; or else a match of the already-captured value. This disambiguation happens when we lower ast nodes to sema nodes as we resolve bound variable names.

§

BindPattern

Fields

§var: Ident
§subpat: Box<Pattern>
§pos: Pos

An operator that binds a variable to a subterm and matches the subpattern.

§

ConstInt

Fields

§val: i128
§pos: Pos

An operator that matches a constant integer value.

§

ConstPrim

Fields

§val: Ident
§pos: Pos

An operator that matches an external constant value.

§

Term

Fields

§sym: Ident
§args: Vec<Pattern>
§pos: Pos

An application of a type variant or term.

§

Wildcard

Fields

§pos: Pos

An operator that matches anything.

§

And

Fields

§subpats: Vec<Pattern>
§pos: Pos

N sub-patterns that must all match.

§

MacroArg

Fields

§index: usize
§pos: Pos

Internal use only: macro argument in a template.

Implementations§

source§

impl Pattern

source

pub fn root_term(&self) -> Option<&Ident>

source

pub fn terms(&self, f: &mut dyn FnMut(Pos, &Ident))

Call f for each of the terms in this pattern.

source

pub fn make_macro_template(&self, macro_args: &[Ident]) -> Pattern

source

pub fn subst_macro_args(&self, macro_args: &[Pattern]) -> Option<Pattern>

source

pub fn pos(&self) -> Pos

Trait Implementations§

source§

impl Clone for Pattern

source§

fn clone(&self) -> Pattern

Returns a copy of the value. Read more
1.0.0 · source§

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

Performs copy-assignment from source. Read more
source§

impl Debug for Pattern

source§

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

Formats the value using the given formatter. Read more
source§

impl PartialEq<Pattern> for Pattern

source§

fn eq(&self, other: &Pattern) -> bool

This method tests for self and other values to be equal, and is used by ==.
1.0.0 · source§

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
source§

impl Eq for Pattern

source§

impl StructuralEq for Pattern

source§

impl StructuralPartialEq for Pattern

Auto Trait Implementations§

Blanket Implementations§

source§

impl<T> Any for Twhere T: 'static + ?Sized,

source§

fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
source§

impl<T> Borrow<T> for Twhere T: ?Sized,

source§

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
source§

impl<T> BorrowMut<T> for Twhere T: ?Sized,

source§

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
source§

impl<T> From<T> for T

source§

fn from(t: T) -> T

Returns the argument unchanged.

source§

impl<T, U> Into<U> for Twhere U: From<T>,

source§

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

source§

impl<T> ToOwned for Twhere T: Clone,

§

type Owned = T

The resulting type after obtaining ownership.
source§

fn to_owned(&self) -> T

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

fn clone_into(&self, target: &mut T)

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

impl<T, U> TryFrom<U> for Twhere U: Into<T>,

§

type Error = Infallible

The type returned in the event of a conversion error.
source§

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
source§

impl<T, U> TryInto<U> for Twhere U: TryFrom<T>,

§

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

The type returned in the event of a conversion error.
source§

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.