tuplemagic

TupleMagic is a Rust library that provides utilities for manipulating tuples through various operations like mapping, filtering, nesting, and reducing. This library supports both value-level and type-level operations on tuples.

Details

TupleMagic transforms tuples into a nested form which allows for varargs-like processing of tuple types. An input tuple of type (A, B, C) becomes the nested form (A, (B, (C, EOT))).

Turning tuples into nested types simplifies filtering and mapping operations because it leverages recursive type structures, which are inherently more adaptable to recursive traits.

Note that some features of this library are only available in macro form as the non-macro form of the operation may be unergonomic (ie: filter and map operations).

Features

• Nesting and Unnesting: Transform tuples into nested structures and vice versa.

# use tuplemagic::*;
let a = (1, 2, 3).nest();

• Mapping: Apply transformations to each element of a tuple based on a type mapper.

# use tuplemagic::*;
type T = (Option<u8>, Option<u16>, Option<()>);
struct RemoveOption {}
impl<T> TypeMap<RemoveOption> for Option<T> {
    type Mapped = T;
}
type U = tuple_mapper!(RemoveOption::map(T));

• Filtering: Include or exclude elements from a tuple based on a predicate.

# use tuplemagic::*;
type T = (u8, u16, Option<()>);
tuple_filter_predicate!(P = { include = (u8, Vec<u8>), exclude = (u16, u32, ~ <T> Option<T>)});
type U = tuple_filter!(P::filter_type(T));

• Reducing: Reduce a tuple to a single value using a reducer.

# use tuplemagic::*;
struct TupleReducerSum;
impl<T> TupleReducer<usize, T> for TupleReducerSum where T: TryInto<usize>,
{
    fn reduce_one(collect: usize, from: T) -> usize {
        collect + from.try_into().unwrap_or_default()
    }
}
let out = TupleReducerSum::reduce((1_u8, 2_u16, 3_u32), 0);

Operations

Features of this crate may be available as macros, traits or both based on ergonomic concerns. The goal of the crate will be to eventually move to a pure trait-based system, but this does not appear possible at this time.

The underlying mechanisms of the macros are subject to change and are not considered stable at this time.

Installation

Add this to your Cargo.toml:

[dependencies]
tuplemagic = "0.x.y"