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Fix some immediate/retained mode confusion

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For future reference:

- Immediate mode = define the tree we want to render
- Retained mode = mutate the tree to what we want it to be

Also, I cleaned up the language a bit.
This commit is contained in:
Isiah Meadows 2017-12-07 21:25:50 -05:00
parent cea17a51c2
commit 3b94cfebee
1 changed files with 3 additions and 3 deletions
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6
docs/vnodes.md
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@ -21,11 +21,11 @@ It may seem wasteful to recreate vnodes so frequently, but as it turns out, mode
For that reason, Mithril uses a sophisticated and highly optimized virtual DOM diffing algorithm to minimize the amount of DOM updates. Mithril *also* generates carefully crafted vnode data structures that are compiled by Javascript engines for near-native data structure access performance. In addition, Mithril aggressively optimizes the function that creates vnodes as well.
The reason Mithril goes to such great lengths to support a rendering model that recreates the entire virtual DOM tree on every render is to provide [retained mode rendering](https://en.wikipedia.org/wiki/Retained_mode), a style of rendering that makes it drastically easier to manage UI complexity.
The reason Mithril goes to such great lengths to support a rendering model that recreates the entire virtual DOM tree on every render is to provide a declarative [immediate mode](https://en.wikipedia.org/wiki/Immediate_mode_(computer_graphics)) API, a style of rendering that makes it drastically easier to manage UI complexity.
To illustrate why retained mode is so important, consider the DOM API and HTML. The DOM API is an [immediate mode](https://en.wikipedia.org/wiki/Immediate_mode_(computer_graphics)) rendering system and requires writing out exact instructions to assemble a DOM tree procedurally. The imperative nature of the DOM API means you have many opportunities to micro-optimize your code, but it also means that you have more chances of introducing bugs and more chances to make code harder to understand.
To illustrate why immediate mode is so important, consider the DOM API and HTML. The DOM API is an imperative [retained mode](https://en.wikipedia.org/wiki/Retained_mode) API and requires 1. writing out exact instructions to assemble a DOM tree procedurally, and 2. writing out other instructions to update that tree. The imperative nature of the DOM API means you have many opportunities to micro-optimize your code, but it also means that you have more chances of introducing bugs and more chances to make code harder to understand.
In contrast, HTML is a retained mode rendering system. With HTML, you can write a DOM tree in a far more natural and readable way, without worrying about forgetting to append a child to a parent, running into stack overflows when rendering extremely deep trees, etc.
In contrast, HTML is closer to an immediate mode rendering system. With HTML, you can write a DOM tree in a far more natural and readable way, without worrying about forgetting to append a child to a parent, running into stack overflows when rendering extremely deep trees, etc.
Virtual DOM goes one step further than HTML by allowing you to write *dynamic* DOM trees without having to manually write multiple sets of DOM API calls to efficiently synchronize the UI to arbitrary data changes.