Struct polytype::Arrow

pub struct Arrow {
    pub arg: Box<Type>,
    pub ret: Box<Type>,
}

A curried function.

Examples

use polytype::{Type, Arrow};

let func = Arrow{
    arg: Box::new(Type::Variable(0)),
    ret: Box::new(Type::Arrow(Arrow{
        arg: Box::new(Type::Variable(1)),
        ret: Box::new(Type::Variable(2)),
    })),
};

assert_eq!(Vec::from(func.args()), vec![&Type::Variable(0), &Type::Variable(1)]);
assert_eq!(func.returns(), &Type::Variable(2));

With the macros:

let func = arrow![tp!(0), tp!(1), tp!(2)];

if let Type::Arrow(arr) = func {
    assert_eq!(Vec::from(arr.args()), vec![&tp!(0), &tp!(1)]);
    assert_eq!(arr.returns(), &tp!(2));
} else { unreachable!() } // we know func is an arrow

Fields

arg: Box<Type>

ret: Box<Type>

Methods

impl Arrow

fn args(&self) -> VecDeque<&Type>

Get all arguments to the function, recursing through curried functions.

fn returns(&self) -> &Type

Get the return type of the function, recursing through curried function returns.

Trait Implementations

impl Debug for Arrow

fn fmt(&self, __arg_0: &mut Formatter) -> Result

Formats the value using the given formatter.

impl Clone for Arrow

fn clone(&self) -> Arrow

Returns a copy of the value.

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

Performs copy-assignment from source.

impl PartialEq for Arrow

fn eq(&self, __arg_0: &Arrow) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, __arg_0: &Arrow) -> bool

This method tests for !=.