How can I achieve something like Phoenix "render_layout" but with multiple block content?

Phoenix Forum Questions / Help
,
1

So I checked the definition of Phoenix View render_layout function and I would like to write something similar to pass multiple blocks to render into differents parts of my layout template. Here is the function I writed in my layout view module:

  def render_banner(assigns, left: left_block, right: right_block) do
    assigns =
      assigns
      |> Map.new()
      |> Map.put(:banner_left_content, left_block)
      |> Map.put(:banner_right_content, right_block)

    render("banner.html", assigns)
  end

But now I don’t know how to use it inside my templates.

I would like to do something like:


<%= LayoutView.render_banner assigns do %>
    <% :left %>
        <h1>TITLE</h1>
        <hr>
        
    <% :right %>
        <img src="/images/img.svg">
        <hr>
<% end %>

I don’t want specifically this syntax, just anything that would be enough readable.
Please can you guide me to implement this?

Thanks

2

This is not exactly for layouts, but I created this a few days ago:

3 Likes
3

If you want something to take a do/end block then that thing has to be a macro, otherwise you take a function as the argument like how Phoenix deals with its form helpers.

1 Like
4

You can actually define a function that takes a block, but it works a little differently to how macros that take a block works. For example,

iex(1)> defmodule Test do
...(1)> def blocky(do: block) do
...(1)> IO.puts("hello from function")
...(1)> block
...(1)> end
...(1)> def test do
...(1)> blocky do
...(1)> IO.puts("hello from block")
...(1)> end
...(1)> end
...(1)> end
{:module, Test, <<...>>, {:test, 0}}
iex(2)> Test.test
hello from block
hello from function
:ok
iex(3)> defmodule Test2 do            
...(3)> defmacrop blocky(do: block) do
...(3)> quote do
...(3)> IO.puts("hello from macro")
...(3)> unquote(block)
...(3)> end
...(3)> end
...(3)> def test do
...(3)> blocky do
...(3)> IO.puts("hello from block")
...(3)> end
...(3)> end
...(3)> end
{:module, Test2, <<...>>, {:test, 0}}
iex(4)> Test2.test
hello from macro
hello from block
:ok

edit: was thinking some more and I realized that you’re kinda right to recommend passing an anonymous function to a function instead of a block, as that will result in the correct order of side effects same as a macro would. Eg.

iex(7)> defmodule Test3 do
...(7)> defp blocky(func) do
...(7)> IO.puts("hello from function")
...(7)> func.()
...(7)> end
...(7)> def test do
...(7)> blocky fn ->
...(7)> IO.puts("hello from anonymous function")
...(7)> end
...(7)> end
...(7)> end
{:module, Test3, <<...>>, {:test, 0}}
iex(8)> Test3.test
hello from function
hello from anonymous function
:ok
1 Like
5

FYI https://stackoverflow.com/a/51452620

1 Like
6

Right, that is what my code above is trying to demonstrate :slight_smile: it works, but not how you probably think it does

1 Like
7

Thanks everyone for your help.

Since I just have two blocks to pass to my function I kind of cheated on Elixir. ^^

I used do and else as keys and it worked.

  def render_banner(assigns, do: left_block, else: right_block) do
    assigns =
      assigns
      |> Map.new()
      |> Map.put(:banner_left_content, left_block)
      |> Map.put(:banner_right_content, right_block)

    LayoutView.render("banner.html", assigns)
  end

Which can be used like this:

<%= render_banner assigns do %>
    <h1><%= translate @post, :title %></h1>
<% else %>
    <%= render "index_searchbar.html", assigns %>
<% end %>

Well it’s maybe a bit semantically weird to use “else” here.

I still plan to dig a little in @LostKobrakai library to find a more elegant solution in the future.