# Announcing Uiua 0.15.0

2025-04-03

---

Uiua 0.15.0 is now available!

You can find the full changelog [here](https://uiua.org/docs/changelog#0.15.0---2025-04-03).

You can download pre-built binaries [here](https://github.com/uiua-lang/uiua/releases).

Uiua is a general purpose, stack-based, array-oriented programming language with a focus on tacit code.

Here are some highlights of this release:

## Data Definitions

Data definitions are a newly stabilized feature that allows names to be given to the rows of heterogeneous arrays. This is similar to structures or classes in other languages.

There is [new tutorial](https://uiua.org/tutorial/Data Definitions) detailing all the features of data definitions, but here are a few examples:

Simple data definitions can be defined following a `~`. We can then use the name of the definition to construct an array, and we can use the field names to access the fields.

```uiua
~Customer {Name Phone Address}
Customer "John Doe" "555-1234" "123 Main St"
Customer~Name .
```

If we want to add functions associated with the data definition, we can put the definition inside a module. We can use a [module import macro](https://www.uiua.org/tutorial/Modules#module-import-macros) to easily access the items in the module.

```uiua
┌─╴Customer
  ~ {Name Phone Address}
  Format   ← $"_ lives at _" ⊃(Name|Address)
  HouseNum ← ⋕▽⊸∊+@0⇡10 Address
└─╴

Customer!(
  New "Bob" "555-1234" "123 Main St"
  $"_'s house number is _" ⊃(Name|HouseNum)

  Format New "Alice" "555-2843" "456 Broadway St"
)
```

Enum-like data definitions can be defined in a module with `|`s. [Pattern matching](https://www.uiua.org/tutorial/Pattern Matching) can be used to do different things based on the variant.

```uiua
┌─╴Shape
  |Circle {Radius}
  |Rectangle {Width Height}
  |Point
  Area ← $Area ⍣(
    ×π˙× °Circle
  | × °Rectangle
  | 0)
  Format ← ⍣(
    $"Circle has radius _" °Circle
  | $"Rectangle is _×_" °Rectangle
  | "Point"
  )
└─╴

Shape!(⊃(Area|Format) Circle 4)
Shape!(⊃(Area|Format) Rectangle 3 5)
```

## [`backward ˜`](https://www.uiua.org/docs/backward) Stabilization

The [`backward ˜`](https://www.uiua.org/docs/backward) modifier has been stabilized. [`backward ˜`](https://www.uiua.org/docs/backward) [`flip :`](https://www.uiua.org/docs/flip)s the arguments of its function.

```uiua
 - 3 5
˜- 3 5
```

```uiua
 map 1_2_3 "abc"
˜map 1_2_3 "abc"
```

```uiua
 ⊂ 0 [1 2 3]
˜⊂ 0 [1 2 3]
```

```uiua
°˜⊂ [1 2 3 4]
```

[`backward ˜`](https://www.uiua.org/docs/backward) is usually used on dyadic functions, but it can also be used on tetradic (4 argument) functions. In this case, it swaps the second and third arguments, leaving the first and fourth arguments unchanged. This can be a useful stack permutation.

```uiua
 ⊟₄ 1 2 3 4
˜⊟₄ 1 2 3 4
```

```uiua
˜∩⬚0↙ ◡˜∩⧻ [1 2 3] [4 5 6 7 8]
```

## Sided Subscripts

Sided subscripts are [subscripts](https://www.uiua.org/docs/subscripts) that instead of changing how a function works based on a number, do it based on a "side", either left or right.

Sided subscripts are formatted from `,<` and `,>`. They are currently only stabilized for [`both ∩`](https://www.uiua.org/docs/both) and [`bracket ⊓`](https://www.uiua.org/docs/bracket). These cases simplify some common stack manipulation patterns.

There is a [short tutorial section](https://www.uiua.org/tutorial/evenmoreargument#sided-subscripts) about them, but here are some simple examples:

```uiua
{∩⌟⊟ 1 2 3}
{∩⌞⊟ 1 2 3}
```

```uiua
{⊓⌟⊂⊟ 1_2 3_4 5_6}
{⊓⌞⊂⊟ 1_2 3_4 5_6}
```

## [`over ,`](https://www.uiua.org/docs/over) Deprecation

The [`over ,`](https://www.uiua.org/docs/over) function has been deprecated in favor of more structured stack manipulation modifiers.

You can read more about this change in the short [blog post](https://www.uiua.org/blog/its-so-over).

## ✨

Thanks to everyone who contributed to this release!

As always, a big thank you to Uiua's wonderful [GitHub sponsors](https://github.com/sponsors/uiua-lang)!

Again, you can find the full changelog for this release [here](https://uiua.org/docs/changelog#0.15.0---2025-04-03).

You can join the [Uiua Discord](https://discord.gg/3r9nrfYhCc) to chat about the language, ask questions, or get help. We also do code challenges and discuss language features!