Replace Templates & Hypertext with Blocks or elm-markdown

[upsiflu]

Current:

1. Templates are written in elm/html, with access to a global Directory of valid routes
2. There is a disabled mechanism to load HTML into custom elements
3. Changes to the layout are stored in an append-only list for undo/redo and time travelling

Proposal:

1. For each template, we create a BLOCK, which is a parametric type that renders to Html.
2. One BLOCK is Hypertext, which simply renders arbitrary Html into a custom element
3. Changes to the BLOCKs are stored in the global append-only list together with layout actions.

How to implement:

Each block is an Elm type. The view may introduce custom-elements, for example for rendering literal Html. An article's content is a list of blocks

It's easy to factor out the type module for a block into a standalone elm-element inside a custom-element as a block protocol block.

The current implementation can render to text :-)

Editor:

A block may have attributes. We can simply add an editor for attributes to the Control.

Scope:

• h2 : String
• p : Html
• LinkList : List String, Layout, Dictionary
• AutoLink : String, Layout, Dictionary
• Essay { heading : String , year : Int , author : String , excerpt : String , link : String }
• Image {description : String, diameter : Int, cls : String, location : String}
• Artist { name : String , bio : Directory -> Html Never , photo : String , wide : Bool }
• Festival {...}
• GalleryEntry { name : String , credits : String , links : Directory -> List (Html Never) , photos : List String , wide : Bool }
• Lab { occurance : Occurrence , title : String , description : Html Never , collage : String , video : Maybe String }
• Event { day : Int , month : Month , year : Int , title : String , description : Maybe String , location : String , facilitator : String , companion : String , country : Maybe String , collage : Three (Image Int String) (Vimeo Int Int) (None) }
• Series : { number : Int, motto : String, events : List Event }
• Collage : Image Int String | Vimeo Int Int etc.

Outlook:

• This is a step closer to a CRDT, and will make future editor-like apps much easier to implement
• Future: Logic can determine
  • how to prune an append-only list (given that most actions invalidate certain previous actions)
  • how to define and resolve conflicts, and converge harmonious remote edits

[upsiflu]

Consideration: use elm-markdown as block description format.

Pro:

• Universal format with custom extension
• there are excellent editor components available in the elm ecosystem
• future proof, low maintenance: will support export to future backend formats and rendition in future frontends
• easy manual editing in the database
• existing importers: from html, odf, pdf etc. to md

Con:

• Loss of WYSIWYG
• custom extensions get lost when exporting (in contrast to block protocol)

lmplementation:

(a) one md per block (b) one md per article, with custom html tags for blocks and helpful error messages

The editor can occupy a new region Source (toggle visibility on small screen; occupy leftmost screen column on wider viewport)

[upsiflu]

Concerning elm-markdown: Experiences gained when implementing github.com/upsiflu/multimedia