pub enum Pattern {
    Var {
        var: Ident,
        pos: Pos,
    },
    BindPattern {
        var: Ident,
        subpat: Box<Pattern>,
        pos: Pos,
    },
    ConstInt {
        val: i64,
        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: i64
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

Call f for each of the terms in this pattern.

Trait Implementations

Returns a copy of the value. Read more

Performs copy-assignment from source. Read more

Formats the value using the given formatter. Read more

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

This method tests for !=.

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

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

The resulting type after obtaining ownership.

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

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

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.