Struct EffectSet 

pub struct EffectSet {
    pub concrete: BTreeSet<String>,
    pub var: Option<u32>,
}

Effect set with an optional row variable.

concrete is the closed lower bound — effect kinds the function definitely uses. var is an open extension point used for effect polymorphism on stdlib higher-order functions: list.map[T, U, E] declares its callback as (T) -> [E] U where E is var: Some(id). At call sites the variable unifies with whatever effect set the actual closure carries, then propagates to the result.

All call sites that compare or merge concrete-only sets continue to work via the helper methods, which delegate to concrete.

Fields

concrete: BTreeSet<String>

var: Option<u32>

Implementations

impl EffectSet

pub fn empty() -> Self

pub fn singleton(s: impl Into<String>) -> Self

pub fn open_var(id: u32) -> Self

An open effect set: just a row variable, no concrete lower bound. Used by stdlib HOF signatures (list.map, list.filter, list.fold, option.map, result.map, result.and_then).

pub fn union(&self, other: &EffectSet) -> EffectSet

pub fn is_subset(&self, other: &EffectSet) -> bool

pub fn extend(&mut self, other: &EffectSet)

pub fn is_open(&self) -> bool

Trait Implementations

impl Clone for EffectSet

fn clone(&self) -> EffectSet

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for EffectSet

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

Formats the value using the given formatter.

impl Default for EffectSet

fn default() -> EffectSet

Returns the “default value” for a type.

impl PartialEq for EffectSet

fn eq(&self, other: &EffectSet) -> 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 Eq for EffectSet

impl StructuralPartialEq for EffectSet