# Markright
[![Build Status](https://travis-ci.org/mudasobwa/markright.svg?branch=master)](https://travis-ci.org/mudasobwa/markright) **The extended, streaming, configurable markdown-like syntax parser, that produces an AST.**
Out of the box is supports the full set of `markdown`, plus some extensions.
The user of this library might easily extend the functionality with her own
markup definition and a bit of elixir code to handle parsing.
There is no one single call to `Regex` used. The whole parsing is done solely
on pattern matching the input binary.
The AST produced is understandable by [`XmlBuilder`](https://github.com/joshnuss/xml_builder).
There are many callbacks available to transform the resulting AST. See below.
## Is it of any good?
It is an incredible piece of handsome lovely software. Sure, it is.
## Installation
If [available in Hex](https://hex.pm/docs/publish), the package can be installed
by adding `markright` to your list of dependencies in `mix.exs`:
```elixir
def deps do
[{:markright, "~> 0.2.0"}]
end
```
## Basic usage
```elixir
@input ~s"""
If [available in Hex](https://hex.pm/docs/publish), the package can be installed
by adding `markright` to your list of dependencies in `mix.exs`:
```elixir
def deps do
[{:markright, "~> 0.2.0"}]
end
```
## Basic Usage
Blah...
"""
assert(
Markright.to_ast(@input) ==
{:article, %{},
[{:p, %{}, [
"If ", {:a, %{href: "https://hex.pm/docs/publish"}, "available in Hex"},
", the package can be installed\nby adding ", {:code, %{}, "markright"},
" to your list of dependencies in ", {:code, %{}, "mix.exs"}, ":"]},
{:pre, %{},
[{:code, %{lang: "elixir"},
"def deps do\n [{:markright, \"~> 0.1.0\"}]\nend"}]},
{:p, %{}, [{:h2, %{}, "Basic Usage"}]}, {:p, %{}, "Blah...\n"}]}
)
```
Yes, for unknown reason headers are yet parsed inside `:p` tag, no idea why.
Suggestions (specifically having the form of _pull requests_) are very welcome.
## HTML generation
```elixir
iex> "Hello, *[address]Aleksei*!"
...> |> Markright.to_ast
...> |> XmlBuilder.generate
"<article>
\t<p>
\t\tHello,
\t\t<strong class=\"address\">Aleksei</strong>
\t\t!
\t</p>
</article>"
```
## Power tools
### Callbacks
One might provide a callback to the call to `to_ast/3`. It will be not only
called back on any AST node found (do not expect them to be called in the
natural order, though,) but it _allows to change the AST on the fly_. Just
return a `%Markright.Continuation` object from the callback, and you are done
(see `markright_test.exs` for inspiration):
```elixir
fun = fn
%Markright.Continuation{ast: {:p, %{}, text}} = cont ->
IO.puts "Currently dealing with `:p` node"
%Markright.Continuation{cont | ast: {:div, %{}, text}}
cont -> cont
end
assert Markright.to_ast(@input, fun) == @output
```
### Make fancy links inside blockquotes
When a last blockquote’s element is a link, make it to show the favicon,
and make the blockquote itself to have `cite` attribute:
```elixir
bq_patch = fn
{:blockquote, bq_attrs, list} when is_list(list) ->
case :lists.reverse(list) do
[{:a, %{href: href} = attrs, text} | t] ->
img = with [capture] <- Regex.run(~r|\Ahttps?://[^/]+|, href) do
{:img,
%{alt: "favicon",
src: capture <> "/favicon.png",
style: "height:16px;margin-bottom:-2px;"},
nil}
end
patched = :lists.reverse([{:br, %{}, nil}, "— ", img, " ", {:a, attrs, text}])
{:blockquote, Map.put(bq_attrs, :cite, href), :lists.reverse(patched ++ t)}
_ -> {:blockquote, bq_attrs, list}
end
other -> other
end
fun = fn %Markright.Continuation{ast: ast} = cont ->
%Markright.Continuation{cont | ast: bq_patch.(ast)}
end
```
### Custom classes
All the “grip” elements (like `*bold*` or `*strike*`) have an option to specify
a class:
```elixir
iex> Markright.to_ast "Hello, *[address]Aleksei*!"
{:article, %{},
[{:p, %{}, ["Hello, ", {:strong, %{class: "address"}, "Aleksei"}, "!"]}]}
```
The above is particularly helpful when writing a rich blog posts over, say,
bootstrap css (or any other css, that provides cool flashes etc.)
### Custom syntax
To add a new syntax is as easy as to put a new value into `config`:
```elixir
config :markright, syntax: [
grip: [
sup: "^^"
]
]
```
Voilà—you have this grip on hand:
```elixir
iex> Markright.to_ast "Hello, ^^Aleksei^^!"
{:article, %{},
[{:p, %{}, ["Hello, ", {:sup, %{}, "Aleksei"}, "!"]}]}
```
### Development
The extensions to syntax are not supposed to be merged into trunk. I am thinking
about creating a welcome plugin-like infrastructure. Suggestions are very welcome.
## Documentation
Visit [HexDocs](https://hexdocs.pm). Our docs can
be found at [https://hexdocs.pm/markright](https://hexdocs.pm/markright).