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lib/earmark_ast_dsl.ex
defmodule EarmarkAstDsl do
import __MODULE__.Table, only: [make_table: 2]
import __MODULE__.Atts, only: [as_list: 1, make_atts: 1, only_atts: 1]
use EarmarkAstDsl.Types
@moduledoc """
[](https://github.com/RobertDober/earmark_ast_dsl/actions)
[](https://coveralls.io/github/RobertDober/earmark_ast_dsl?branch=master)
[](https://hex.pm/packages/earmark_ast_dsl)
[](https://hex.pm/packages/earmark_ast_dsl)
[](https://hex.pm/packages/earmark_ast_dsl)
EarmarkAstDsl is a toolset to generate EarmarkParser conformant AST Nodes version 1.4.6 and on,
which is the _always return quadruples_ version.
Its main purpose is to remove boilerplate code from Earmark and
EarmarkParser tests.
Documentation for `EarmarkAstDsl`.
### `tag`
The most general helper is the tag function:
iex(1)> tag("div", "Some content")
{"div", [], ["Some content"], %{}}
Content and attributes can be provided as arrays, ...
iex(2)> tag("p", ~w[Hello World], class: "hidden")
{"p", [{"class", "hidden"}], ["Hello", "World"], %{}}
... or maps:
iex(3)> tag("p", ~w[Hello World], %{class: "hidden"})
{"p", [{"class", "hidden"}], ["Hello", "World"], %{}}
#### Annotations (as implemented in `EarmarkParser` >= v1.4.16)
In order to not overload tha API for `tag/2`, `tag/3` and `tag/4` we offer the general
`tag_annotated` function
iex(4)> tag_annotated("header", "content", "annotation")
{"header", [], ["content"], %{annotation: "annotation"}}
in this case atts come last
iex(5)> tag_annotated("header", "content", "annotation", class: "two")
{"header", [{"class", "two"}], ["content"], %{annotation: "annotation"}}
### Shortcuts for `p` and `div`
iex(6)> p("A para")
{"p", [], ["A para"], %{}}
iex(7)> div(tag("span", "content"))
{"div", [], [{"span", [], ["content"], %{}}], %{}}
#### Annotations
iex(8)> p_annotated("", "%% green")
{"p", [], [""], %{annotation: "%% green"}}
and with attributes
iex(9)> div_annotated("", "%% green", class: "five", data: 2)
{"div", [{"class", "five"}, {"data", "2"}], [""], %{annotation: "%% green"}}
More helpers, which are less common are described on their functiondocs
"""
@spec div(content_t(), free_atts_t()) :: ast_t()
def div(content \\ [], atts \\ []), do: tag("div", content, atts)
@spec div_annotated(content_t(), any(), free_atts_t()) :: ast_t()
def div_annotated(content, annotation, atts \\ []), do: tag_annotated("div", content, annotation, atts)
@spec p(content_t(), free_atts_t()) :: ast_t()
def p(content \\ [], atts \\ []), do: tag("p", content, atts)
@spec p_annotated(content_t(), any(), free_atts_t()) :: ast_t()
def p_annotated(content, annotation, atts \\ []), do: tag_annotated("p", content, annotation, atts)
@doc """
A convenient shortcut for the often occurring `<pre><code>` tag chain
iex(10)> pre_code("hello")
{"pre", [], [{"code", [], ["hello"], %{}}], %{}}
"""
@spec pre_code(content_t(), free_atts_t()) :: ast_t()
def pre_code(content, atts \\ []) do
_tag_chain(["pre", "code"], as_list(content), atts)
end
@doc """
The annotation adding helper
iex(11)> pre_code_annotated("code", "@@lang=elixir")
{"pre", [], [{"code", [], ["code"], %{annotation: "@@lang=elixir"}}], %{}}
"""
@spec pre_code_annotated(content_t(), any, free_atts_t()) :: ast_t()
def pre_code_annotated(content, annotation, atts \\ []) do
case pre_code(content, atts) do
{"pre", atts1, [{"code", atts2, content2, meta2}], meta1} ->
{"pre", atts1, [{"code", atts2, content2, Map.put(meta2, :annotation, annotation)}], meta1}
end
end
@doc """
### Tables
Tables are probably the _raison d'être_ ot this little lib, as their ast is quite verbose, as we will see
here:
iex(12)> table("one cell only") # and look at the output
{"table", [], [
{"tbody", [], [
{"tr", [], [
{"td", [{"style", "text-align: left;"}], ["one cell only"], %{}}
], %{}}
], %{}}
], %{}}
Now if we want a header and have some more data:
iex(13)> table([~w[1-1 1-2], ~w[2-1 2-2]], head: ~w[left right]) # This is quite verbose!
{"table", [], [
{"thead", [], [
{"tr", [], [
{"th", [{"style", "text-align: left;"}], ["left"], %{}},
{"th", [{"style", "text-align: left;"}], ["right"], %{}},
], %{}}
], %{}},
{"tbody", [], [
{"tr", [], [
{"td", [{"style", "text-align: left;"}], ["1-1"], %{}},
{"td", [{"style", "text-align: left;"}], ["1-2"], %{}},
], %{}},
{"tr", [], [
{"td", [{"style", "text-align: left;"}], ["2-1"], %{}},
{"td", [{"style", "text-align: left;"}], ["2-2"], %{}},
], %{}}
], %{}}
], %{}}
And tables can easily be aligned differently in Markdown, which makes some style helpers
very useful
iex(14)> table([~w[1-1 1-2], ~w[2-1 2-2]],
...(14)> head: ~w[alpha beta],
...(14)> text_aligns: ~w[right center])
{"table", [], [
{"thead", [], [
{"tr", [], [
{"th", [{"style", "text-align: right;"}], ["alpha"], %{}},
{"th", [{"style", "text-align: center;"}], ["beta"], %{}},
], %{}}
], %{}},
{"tbody", [], [
{"tr", [], [
{"td", [{"style", "text-align: right;"}], ["1-1"], %{}},
{"td", [{"style", "text-align: center;"}], ["1-2"], %{}},
], %{}},
{"tr", [], [
{"td", [{"style", "text-align: right;"}], ["2-1"], %{}},
{"td", [{"style", "text-align: center;"}], ["2-2"], %{}},
], %{}}
], %{}}
], %{}}
Some leeway is given for the determination of the number of columns,
bear in mind that Markdown only supports regularly shaped tables with
a fixed number of columns.
Problems might arise when we have a table like the following
| alpha |
| beta *gamma* |
where the first cell contains one element, but the second two, we can
hint that we only want one by grouping into tuples
iex(15)> table(["alpha", {"beta", tag("em", "gamma")}])
{"table", [], [
{"tbody", [], [
{"tr", [], [
{"td", [{"style", "text-align: left;"}], ["alpha"], %{}},
], %{}},
{"tr", [], [
{"td", [{"style", "text-align: left;"}], ["beta", {"em", [], ["gamma"], %{}}], %{}}
], %{}}
], %{}}
], %{}}
"""
@spec table(table_t(), free_atts_t()) :: ast_t()
def table(rows, atts \\ [])
def table(rows, atts) when is_binary(rows), do: table([rows], atts)
def table(rows, atts) do
tag("table", make_table(rows, atts), only_atts(atts))
end
@doc """
This is the base helper which emits a tag with its content, attributes and metadata can be added
at the user's convenience
iex(16)> tag("div")
{"div", [], [], %{}}
With content,
iex(17)> tag("span", "hello")
{"span", [], ["hello"], %{}}
... and attributes,
iex(18)> tag("code", "let it(:be_light)", [class: "inline"])
{"code", [{"class", "inline"}], ["let it(:be_light)"], %{}}
... and metadata
iex(19)> tag("div", "content", [], %{verbatim: true})
{"div", [], ["content"], %{verbatim: true}}
"""
@spec tag(maybe(binary()), maybe(content_t()), free_atts_t(), map()) :: ast_t()
def tag(name, content \\ [], atts \\ [], meta \\ %{})
def tag(name, nil, atts, meta), do: tag(name, [], atts, meta)
def tag(name, content, atts, meta) when is_binary(content) or is_tuple(content),
do: tag(name, [content], atts, meta)
def tag(name, content, atts, meta) do
{to_string(name), make_atts(atts), content, meta}
end
@doc """
A convience function for easy addition of an annotation to the meta map
"""
@spec tag_annotated(binary(), maybe(content_t()), any(), free_atts_t()) :: ast_t()
def tag_annotated(name, content, annotation, atts \\ []), do: tag(name, content, atts, %{annotation: annotation})
@doc """
Void tags are just convenient shortcats for calls to `tag` with the second argument
`nil` or `[]`
One cannot pass metadata to a void_tag call
iex(20)> void_tag("hr")
{"hr", [], [], %{}}
iex(21)> void_tag("hr", class: "thin")
{"hr", [{"class", "thin"}], [], %{}}
"""
@spec void_tag(binary(), free_atts_t()) :: ast_t()
def void_tag(name, atts \\ [])
def void_tag(name, atts) do
tag(name, nil, atts)
end
@doc """
Again the annotated version is available
iex(22)> void_tag_annotated("br", "// break")
{"br", [], [], %{annotation: "// break"}}
iex(23)> void_tag_annotated("wbr", "// for printer", class: "nine")
{"wbr", [{"class", "nine"}], [], %{annotation: "// for printer"}}
"""
@spec void_tag_annotated(binary(), any(), free_atts_t()) :: ast_t()
def void_tag_annotated(name, annotation, atts \\ []),
do: tag_annotated(name, nil, annotation, atts)
@doc """
vtags are tags from verbatim html
iex(24)> vtag("div", "hello")
{"div", [], ["hello"], %{verbatim: true}}
Attributes can be provided, of course
iex(25)> vtag("div", ["some", "content"], [{"data-lang", "elixir"}])
{"div", [{"data-lang", "elixir"}], ["some", "content"], %{verbatim: true}}
"""
@spec vtag(maybe(binary()), maybe(content_t()), free_atts_t()) :: ast_t()
def vtag(name, content \\ [], atts \\ [])
def vtag(name, content, atts) do
tag(name, content, atts, %{verbatim: true})
end
@doc """
Verbatim tags still can be annotated and therefore we have this helper
iex(26)> vtag_annotated("i", "emphasized", "-- verbatim", printer: "no")
{"i", [{"printer", "no"}], ["emphasized"], %{annotation: "-- verbatim", verbatim: true}}
"""
@spec vtag_annotated(binary(), maybe(content_t()), any(), free_atts_t()) :: ast_t()
def vtag_annotated(name, content, annotation, atts \\ []) do
tag(name, content, atts, %{annotation: annotation, verbatim: true})
end
@spec _tag_chain(list(String.t()), content_t(), free_atts_t()) :: ast_t()
defp _tag_chain(tags, content, atts) do
tags
|> Enum.reverse
|> Enum.reduce(content, fn next, content -> [{next, make_atts(atts), content, %{}}] end)
|> hd()
end
end
# SPDX-License-Identifier: Apache-2.0