# AtBackslash

`AtBackslash`

exports a macro `@\`

to easily create functions that
work with named tuples as input and/or output.

The symbol literal like `:x`

in the tuple argument is expanded to be
the property/field of the named tuple of the input and output:

```
julia> using AtBackslash
julia> (x = 1, y = 2, z = 3) |> @\(:x, :y)
(x = 1, y = 2)
```

It also supports normal "verbose" syntax for creating a named tuple:

```
julia> (x = 1, y = 2) |> @\(x = :x, y = :y)
(x = 1, y = 2)
```

which is handy when adding new properties:

```
julia> (x = 1, y = 2) |> @\(:x, z = :x + :y)
(x = 1, z = 3)
```

The argument can be explicitly referred to by `_`

:

```
julia> (x = 1, y = 2) |> @\(_..., z = :x + :y)
(x = 1, y = 2, z = 3)
```

```
julia> (x = 1, y = 2) |> @\_.x
1
```

```
julia> 1 |> @\(x = _, y = 2_)
(x = 1, y = 2)
```

Automatic conversions of `:x`

and `(; :x, :y)`

work at any level of
expression:

```
julia> (x = 1, y = 2) |> @\ merge((; :x, :y), (a = :x, b = :y))
(x = 1, y = 2, a = 1, b = 2)
```

```
julia> (x = 1, y = 2) |> @\(:x < :y < 3)
true
```

Use `$:x`

to avoid automatic conversion to `_.x`

:

```
julia> (x = 1, y = 2) |> @\(x = $:x, :y)
(x = :x, y = 2)
```

Use plain names to refer to the variables in the outer scope:

```
julia> let z = 3
(x = 1, y = 2) |> @\(:x, :y, z)
end
(x = 1, y = 2, z = 3)
```

The input can be any object that support `getproperty`

. For example,
it works with `Complex`

:

```
julia> 1 + 2im |> @\(:re, :im)
(re = 1, im = 2)
```