Enum Expr 

pub enum Expr {
    Var(Arc<str>),
    Lam(Arc<str>, Box<Self>),
    App(Box<Self>, Box<Self>),
    Lit(Literal),
    Record(Vec<(Arc<str>, Self)>),
    List(Vec<Self>),
    Field(Box<Self>, Arc<str>),
    Index(Box<Self>, Box<Self>),
    Match {
        scrutinee: Box<Self>,
        arms: Vec<(Pattern, Self)>,
    },
    Let {
        name: Arc<str>,
        value: Box<Self>,
        body: Box<Self>,
    },
    Builtin(BuiltinOp, Vec<Self>),
}

An expression in the pure functional language.

All variants are serializable, content-addressable, and evaluate deterministically on any platform (including WASM).

Variants

Var(Arc<str>)

Variable reference.

Lam(Arc<str>, Box<Self>)

Lambda abstraction: λparam. body.

App(Box<Self>, Box<Self>)

Function application: func(arg).

Lit(Literal)

Literal value.

Record(Vec<(Arc<str>, Self)>)

Record construction: { name: expr, ... }.

List(Vec<Self>)

List construction: [expr, ...].

Field(Box<Self>, Arc<str>)

Field access: expr.field.

Index(Box<Self>, Box<Self>)

Index access: expr[index].

Match

Pattern matching: match scrutinee { pat => body, ... }.

Fields

scrutinee: Box<Self>

The value being matched against.

arms: Vec<(Pattern, Self)>

Arms: (pattern, body) pairs tried in order.

Let

Let binding: let name = value in body.

Fields

name: Arc<str>

The bound variable name.

value: Box<Self>

The value to bind.

body: Box<Self>

The body where the binding is visible.

Builtin(BuiltinOp, Vec<Self>)

Built-in operation applied to arguments.

Implementations

impl Expr

pub fn var(name: impl Into<Arc<str>>) -> Self

Create a variable expression.

pub fn lam(param: impl Into<Arc<str>>, body: Self) -> Self

Create a lambda expression.

pub fn app(func: Self, arg: Self) -> Self

Create an application expression.

pub fn let_in(name: impl Into<Arc<str>>, value: Self, body: Self) -> Self

Create a let-binding expression.

pub fn field(expr: Self, name: impl Into<Arc<str>>) -> Self

Create a field access expression.

pub const fn builtin(op: BuiltinOp, args: Vec<Self>) -> Self

Create a builtin operation applied to arguments.

Trait Implementations

impl Clone for Expr

fn clone(&self) -> Expr

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Expr

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for Expr

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Hash for Expr

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for Expr

fn eq(&self, other: &Expr) -> 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 Serialize for Expr

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Eq for Expr

impl StructuralPartialEq for Expr