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§

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 !=. The default implementation is almost always sufficient, and should not be overridden without very good reason. Read more

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.