Crate canrun

Canrun is a logic programming library inspired by the *Kanren family of language DSLs.

Status: Exploratory and Highly Experimental

I'm still quite new to both Rust and logic programming, so there are likely to be rough edges. At best the goal is to be a useful implementation of the core concepts of a Kanren in way that is idiomatic to Rust. At worst it may just be a poor misinterpretation with fatal flaws.

Quick Start

use canrun::{Goal, both, unify, var};
use canrun::domains::example::I32;

let x = var();
let y = var();
let goal: Goal<I32> = both(unify(x, y), unify(1, x));
let result: Vec<_> = goal.query(y).collect();
assert_eq!(result, vec![1])

Modules

domains	Constrain the set of types that you can reason about in a particular context.
goal	Make declarative assertions about the relationships between values.
state	Track value bindings and constraints during the evaluation process.
util	Assorted helpers, especially for testing.
value	Contain individual resolved values or variables that can be bound through unification.

Macros

all	Create a goal that only succeeds if all sub-goals succeed.
any	Create a goal that yields a state for every successful sub-goal.
domain	Generate Domain structs and other associated types and impls.
ltup	Create a tuple of logical values with automatic IntoVal wrapping.
val	Easy conversion of LVar<T> and T values into Val<T>.

Structs

Goal	A container of one of many possible types of goals.
LVar	A logical variable that represents a potential value of type T.
ResolvedState	Derived from an open State, depending on the constraints that have been applied.
State	The core struct used to contain and manage value bindings.

Enums

Val	The possible states a value can be in.

Traits

Domain	Manage values for a set of specific types.
DomainType	Allows a State to retrieve values of a specific type from a domain.
Fork	Fork a State into zero or more alternate states.
IntoVal	Helper for converting into Val<T>.
IterResolved	Iterate over ResolvedStates.
Query	Derive reified values potential resolved states.
ReifyIn	Extract a fully resolved T from a Val<T>.
UnifyIn	How compatible values are matched with each other.

Functions

assert_1	Create a projection goal that succeeds if the resolved value passes an assertion test.
assert_2	Create a projection goal that succeeds if the resolved values pass an assertion test.
both	Create a goal that only succeeds if both sub-goals succeed.
custom	Create a goal that gives access to the underlying State struct.
either	Create a goal that succeeds if either sub-goal succeed.
lazy	Create a goal that is generated via callback just as it is about to be evaluated.
map_1	Create a projection goal that allows deriving one resolved value from the other.
map_2	Create a projection goal that allows deriving one resolved value from the other two.
project_1	Create a projection goal that allows creating a new goal based on the resolved value.
project_2	Create a projection goal that allows creating a new goal based on the resolved values.
unify	Create a goal that attempts to unify two values with each other.
var	Create a new logical var.

Type Definitions

StateIter

Type alias for an Iterator of States