# Unique-Words Sigil
***`~u`*** **sigil ·** unique-word strings, lists, HTML classes, checked at compile time
Ideal for HTML classes used with templating systems such as [Temple](https://github.com/mhanberg/temple):
```elixir
div class: ~u"flex items-center flex" do # (CompilerError) Duplicate word: flex
p class: ~u"text-lg font-bold
text-gray text-lg" # ────── (CompilerError) Duplicate word: text-lg
do # └───── Effortless multiline classes promote readability
"Hello world"
end
end
```
## Installation
Add `unique_words_sigil` to your list of dependencies in `mix.exs`:
```elixir
def deps do
[
{:unique_words_sigil, "~> 0.1.0"}
]
end
```
then
```
mix deps.get
```
Start up a repl:
```elixir
$ iex -S mix
iex> import UniqueWordsSigil
iex> ~u" hello world "
"hello world" # Whitespace trimmed, extra space & newlines ignored.
iex> ~u" hello world hello again"
** (ArgumentError) Duplicate word: hello # Duplicate words prevented ⚔️
iex> {~u" hello world "l, ~u" hello world "a, ~u" hello world "c}
{["hello", "world"], [:hello, :world], [~c"hello", ~c"world"]}
# String lists, atoms, charlists, oh my! (parity with ~w sigil)
```
## Usage
```elixir
~u"hello world" -> "hello world"
~u" hello world " -> "hello world" # whitespace is trimmed and "collapsed"
~u" hello world "l -> ["hello", "world"]
~u" hello world "a -> [:hello, :world]
~u" hello world "c -> [~c"hello", ~c"world"]
~u" hi hi " -> (ArgumentError) Duplicate word: hi
~u" hi-hi hi-hi "w -> "hi-hi hi-hi" Warning: Duplicate word: hi-hi
~u" hi hi "wl -> ["hi", "hi"] Warning: Duplicate word: hi
~u" hi-hi hi-hi "aw -> [:"hi-hi", :"hi-hi"] Warning: Duplicate word: hi-hi
~u" hi hi "cw -> [~c"hi", ~c"hi"] Warning: Duplicate word: hi
~~~~~~~~~~~~~~~~~~
```
***`~u`*** works well with interpolation and multi-line strings:
```elixir
a href: ~p"/link/url"
class: ~u"flex items-center h-8 text-sm pl-8 pr-3
#{if(@active, do: ~u"bg-slate", else: ~u"hover:bg-slate")}
items-center text-blue" # ────── Duplicate word: items-center
do # └─ Effortless multiline classes promote readability
"Hello world"
end
```
[!IMPORTANT]
By default, interpolations WON'T be uniqueness-checked, since they aren't known at compile-time.
***`i`*** modifier may be added to check uniqueness of interpolated sections at runtime:
```
~u" hi hello \#{"h" <> "i"}"i -> (RuntimeError) Duplicate word: hi
```
Interpolation uniqueness-checking is disabled unless ***`i`*** modifier is set to avoid
unintended runtime overhead.
When `Mix.env() == :prod`, interpolation uniqueness-checking will ALWAYS be disabled
even when ***`i`*** modifier is set (this behavior caters to the most common use-case).
# License
MIT
