Enum Pattern

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

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

Variants

Var

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.

Fields

var: Ident

pos: Pos

BindPattern

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

Fields

var: Ident

subpat: Box<Pattern>

pos: Pos

ConstBool

An operator that matches a constant boolean value.

Fields

val: bool

pos: Pos

ConstInt

An operator that matches a constant integer value.

Fields

val: i128

pos: Pos

ConstPrim

An operator that matches an external constant value.

Fields

val: Ident

pos: Pos

Term

An application of a type variant or term.

Fields

sym: Ident

args: Vec<Pattern>

pos: Pos

Wildcard

An operator that matches anything.

Fields

pos: Pos

And

N sub-patterns that must all match.

Fields

subpats: Vec<Pattern>

pos: Pos

MacroArg

Internal use only: macro argument in a template.

Fields

index: usize

pos: Pos

Implementations

impl Pattern

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

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

Call f for each of the terms in this pattern.

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

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

pub fn pos(&self) -> Pos

Trait Implementations

impl Clone for Pattern

fn clone(&self) -> Pattern

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Pattern

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

Formats the value using the given formatter.

impl PartialEq for Pattern

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

Tests for self and other values to be equal, and is used by ==.

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

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

impl ToSExpr for Pattern

fn to_sexpr(&self) -> SExpr

Convert the given value to an S-expression.

impl Eq for Pattern

impl StructuralPartialEq for Pattern