dhall-haskell/dhall-text/README.md

# `dhall-text 1.0.14`

[![Hackage](https://img.shields.io/hackage/v/dhall-text.svg)](https://hackage.haskell.org/package/dhall-text)

This `dhall-text` package provides a `dhall-to-text` executable which you can
use to template text using the Dhall configuration language.

For example, suppose you save the following files to your current directory:

```haskell
$ cat Person
-- Dhall is a typed programming language

-- This file is the type of an anonymous record
{ name : Text, upvotes : Natural }
```

```haskell
$ cat people
-- Dhall natively supports lists and anonymous records

[ { name = "Maria" , upvotes = 14 }
, { name = "Jordan", upvotes =  2 }
, { name = "Pranav", upvotes =  1 }
]

-- This file has type:
--
--     ./people : List { name : Text, upvotes : Natural }
--
-- ... or just:
--
--     ./people : List ./Person
```

```haskell
$ cat make-item
    -- You can define anonymous functions in Dhall using a backslash (i.e. `\`)
    \(person : ./Person)  -- You can import any type or expression by its path

    -- Dhall supports multiline strings that strip leading whitespace and Dhall
    -- supports string interpolation, too, using `${...}` syntax
->   ''
    <li class="list-group-item">
      <span class="badge">${Natural/show person.upvotes}</span>
      ${person.name}
    </li>
    ''

-- This file has type:
--
--     ./make-item : ./Person -> Text
```

```haskell
$ cat make-items
    -- You can also import any type or expression by its URL
    let List/map =  https://raw.githubusercontent.com/dhall-lang/Prelude/302881a17491f3c72238975a6c3e7aab603b9a96/List/map
in  let Text/concat =  https://raw.githubusercontent.com/dhall-lang/Prelude/302881a17491f3c72238975a6c3e7aab603b9a96/Text/concat
in  \(people : List ./Person)
->   Text/concat (List/map ./Person Text ./make-item people)

-- This file has type:
--
--     ./make-items : List ./Person -> Text
```

Templating HTML is just ordinary function application:

```bash
$ dhall-to-text <<< './make-items ./people'
<li class="list-group-item">
  <span class="badge">14</span>
  Maria
</li>

<li class="list-group-item">
  <span class="badge">2</span>
  Jordan
</li>

<li class="list-group-item">
  <span class="badge">1</span>
  Pranav
</li>

```

To learn more about the Dhall configuration language,
[read the tutorial](https://hackage.haskell.org/package/dhall/docs/Dhall-Tutorial.html)

## Quick start

If you have Nix then you can install this package using:

```bash
$ nix-env --install --file default.nix
```