Notes on Hoplon/Blaze

[ro6]

To understand how Blaze does reactive dom updates via Tracker.autorun:

• https://github.com/meteor/blaze/blob/master/packages/blaze/view.js#L334
• https://github.com/meteor/blaze/blob/master/packages/blaze/materializer.js#L49 is analagous to (->node) https://github.com/hoplon/hoplon/blob/master/src/hoplon/core.cljs#L110
• Reactive attribute updates are scoped to the life of the parentView https://github.com/meteor/blaze/blob/master/packages/blaze/materializer.js#L140
• Autorun is stopped on element teardown https://github.com/meteor/blaze/blob/master/packages/blaze/materializer.js#L148
• Detect need to do teardown using jQuery trick https://github.com/meteor/blaze/blob/master/packages/blaze/dombackend.js#L112
• Sounds like DOMRange is just an update-and-sync layer over actual dom nodes https://github.com/meteor/blaze/blob/master/packages/blaze/domrange.js
• Special handling of if conditionals in templates https://github.com/meteor/blaze/blob/master/packages/blaze/builtins.js#L73
• Looks like the renderFunction passed to materialize the view returns an htmljs representation of the content to be rendered https://github.com/meteor/blaze/blob/master/packages/blaze/view.js#L348
• Place where Spacebars tree is actually compiled to the code that produces htmljs https://github.com/meteor/blaze/blob/master/packages/spacebars-compiler/compiler.js#L16

Hoplon uses protocols defined on dom elements themselves to make a lot of the 'magic' work:

• Invoking a tag function causes it to be added to the document, then it's invoke impl to be run https://github.com/hoplon/hoplon/blob/master/src/hoplon/core.cljs#L388 which parses the various arg formats Hoplon allows for specifying elements, then adds the attributes and children to the created node as specified by the args https://github.com/hoplon/hoplon/blob/master/src/hoplon/core.cljs#L343
• Right now the only ICustomAttribute inhabitant is Clojure's Keyword type, which just ends up mapping to a normal html attribute key/value pair when parsed, but the type of the value is checked to determine whether it should be a normal attr, reactive attr, or event handler https://github.com/hoplon/hoplon/blob/master/src/hoplon/core.cljs#L262
• Good docs on the various dispatch targets of the do!/on! multimethods https://github.com/hoplon/hoplon/wiki/HTML-attributes-and-JS-events-(on!,-do!). It seems like the standard uses map to the keyword targets without a trailing /*, not sure yet how those are different except that they seem to accept a single key/value pair rather than a key and map as a value. They all end up in the same calls to set some aspect of the element using a map of key/values, ie the /* versions are reformed into a map before execution, so these versions are probably just to handle the various syntaxes that Hoplon allows for specifying the element.

Based on the wiki, it looks like Hoplon uses the jquery backend implementations of the do! and on! multimethods by default, via the expansion of the (page) macro https://github.com/hoplon/hoplon/wiki/How-is-a-hl-file-different%3F https://github.com/hoplon/hoplon/blob/master/src/hoplon/jquery.cljs#L40