Iron v1.1.2

Introduction

This release adds multiple improvements to Iron without breaking changes.

Features

New alias for Constrained[A, B]

The old alias A ==> B is replaced by A / B to fit the set notation in maths: S / P(x)

Algebra system

A new algebra system that allows user to chain operators of the same algebra type and to write their constraints in a more mathematical way.
From #35 :

• Add placeholder type ??. Other candidates ?, _ and ??? are already taken.
• Constraints can now belong to a specific algebra
• Algebra entry points can be used with the ?? placeholder: Double / (-1d < ?? < 1d) desugars to Double / (Greater[-1d] && Less[1d]). It is also possible to use different constraints as long as they belong to the same algebra.
• Algebra elements of the same type can be chained. -1d < ?? < 1d < 2d < ....
  Note: chaining is disallowed in before the placeholder ?? to keep allowing Double < 1d and similar syntax. For example, -1 < ?? is allowed but -2d < -1d < ?? isn't.

Composed constraints now support compile-time evaluation

And, Not, Or and similar constraints can now be evaluated at compile-time. Example:

def foo(x: Double / (Divisible[2d] && Greater[0d])): Unit = ???
foo(1d) //compile-time error
foo(-2d) //compile-time error
foo(2d) //This is fine

Iron Numeric

Iron numeric was updated to take advantage of the mentioned features. Version of this update: 1.1-1.0.1

Test it

Here is an interactive example using the described changes.

Code

import io.github.iltotore.iron.*, constraint.{*, given}, numeric.constraint.{*, given}

def acos(x: Double / ((-1d <= ?? <= 1d) DescribedAs "x should be a cosinus")): Refined[Double] = x.map(Math.acos)

println(acos(1d))