Enum Pattern 

pub enum Pattern {
    Wildcard,
    Var(String),
    Literal(Literal),
    Tuple(Vec<Pattern>),
    Variant {
        variant: String,
        patterns: Vec<Pattern>,
    },
}

Pattern in a match expression.

Patterns can match literals, variables, wildcards, tuples, and DU variants. Issue #27 supports basic patterns; Issue #28 will add lists/arrays.

Variants

Wildcard

Wildcard pattern (_) - matches anything

Var(String)

Variable pattern (x) - binds matched value to variable

Literal(Literal)

Literal pattern (42, true, “hello”) - matches exact value

Tuple(Vec<Pattern>)

Tuple pattern ((p1, p2, …)) - matches tuples

Variant

Variant pattern (Some(x), Left, Circle(r)) - matches DU constructors

Fields

variant: String

Variant constructor name (e.g., “Some”, “None”, “Circle”)

patterns: Vec<Pattern>

Nested patterns for variant fields (empty for simple variants)

Implementations

impl Pattern

pub fn is_wildcard(&self) -> bool

Returns true if this pattern is a wildcard.

pub fn is_var(&self) -> bool

Returns true if this pattern is a variable.

pub fn is_literal(&self) -> bool

Returns true if this pattern is a literal.

pub fn is_tuple(&self) -> bool

Returns true if this pattern is a tuple.

pub fn as_var(&self) -> Option<&str>

Returns the variable name if this is a Var, otherwise None.

pub fn as_literal(&self) -> Option<&Literal>

Returns the literal value if this is a Literal, otherwise None.

pub fn as_tuple(&self) -> Option<&Vec<Pattern>>

Returns the tuple patterns if this is a Tuple, otherwise None.

pub fn is_variant(&self) -> bool

Returns true if this pattern is a variant.

pub fn as_variant(&self) -> Option<(&str, &Vec<Pattern>)>

Returns the variant name and patterns if this is a Variant, otherwise None.

Trait Implementations

impl Clone for Pattern

fn clone(&self) -> Pattern

Returns a duplicate of the value.

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 Display 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 ==.

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 StructuralPartialEq for Pattern