From 6460501a446ae52e15fba0e8368c1a7d22fc288e Mon Sep 17 00:00:00 2001
From: Blaž Hrastnik
Date: Sun, 30 May 2021 17:52:46 +0900
Subject: Update architecture.md

---
 docs/architecture.md | 140 +++++++++++++++++++++++++++------------------------
 1 file changed, 75 insertions(+), 65 deletions(-)

(limited to 'docs')

diff --git a/docs/architecture.md b/docs/architecture.md
index 13cdab5e..17ef296d 100644
--- a/docs/architecture.md
+++ b/docs/architecture.md
@@ -8,68 +8,78 @@
 | helix-term   | Terminal UI                                            |
 | helix-tui    | TUI primitives, forked from tui-rs, inspired by Cursive |
 
-# Notes
-
-- server-client architecture via gRPC, UI separate from core
-- multi cursor based editing and slicing
-- WASM based plugins (builtin LSP & fuzzy file finder)
-
-Structure similar to codemirror:
-
-- text (ropes)
-- transactions
-  - changes
-  - invert changes (generates a revert)
-  - annotations (time changed etc)
-  - state effects
-  - additional editor state as facets
-- snapshots as an async view into current state
-- selections { anchor (nonmoving), head (moving) from/to } -> SelectionSet with a primary
-  - cursor is just a single range selection
-- markers
-  track a position inside text that synchronizes with edits
-- { doc, selection, update(), splice, changes(), facets, tabSize, identUnit, lineSeparator, changeFilter/transactionFilter to modify stuff before }
-- view (actual UI)
-- viewport(Lines) -> what's actually visible
-- extend the view via Decorations (inline styling) or Components (UI)
-    - mark / wieget / line / replace decoration
-- commands (transform state)
-- movement
-- selection extension
-- deletion
-- indentation
-- keymap (maps keys to commands)
-- history (undo tree via immutable ropes)
-  - undoes transactions via reverts
-- (collab mode)
-- gutter (line numbers, diagnostic marker, etc) -> ties into UI components
-- rangeset/span -> mappable over changes (can be a marker primitive?)
-- syntax (treesitter)
-- fold
-- selections (select mode/multiselect)
-- matchbrackets
-- closebrackets
-- special-chars (shows dots etc for specials)
-- panel (for UI: file pickers, search dialogs, etc)
-- tooltip (for UI)
-- search (regex)
-- lint (async linters)
-- lsp
-- highlight
-- stream-syntax
-- autocomplete
-- comment (gc, etc for auto commenting)
-- snippets
-- terminal mode?
-
-- plugins can contain more commands/ui abstractions to use elsewhere
-- languageData as presets for each language (syntax, indent, comment, etc)
-
-Vim stuff:
-- motions/operators/text objects
-- full visual mode
-- macros
-- jump lists
-- marks
-- yank/paste
-- conceal for markdown markers, etc
+
+This document contains a high-level overview of Helix internals.
+
+> NOTE: Use `cargo doc --open` for API documentation as well as dependency
+> documentation.
+
+## Core
+
+The core contains basic building blocks used to construct the editor. It is
+heavily based on [CodeMirror 6](https://codemirror.net/6/docs/). The primitives
+are functional: most operations won't modify data in place but instead return
+a new copy.
+
+The main data structure used for representing buffers is a `Rope`. We re-export
+the excellent [ropey](https://github.com/cessen/ropey) library. Ropes are cheap
+to clone, and allow us to easily make snapshots of a text state.
+
+Multiple selections are a core editing primitive. Document selections are
+represented by a `Selection`. Each `Range` in the selection consists of a moving
+`head` and an immovable `anchor`. A single cursor in the editor is simply
+a selection with a single range, with the head and the anchor in the same
+position.
+
+Ropes are modified by constructing an OT-like `Transaction`. It's represents
+a single coherent change to the document and can be applied to the rope.
+A transaction can be inverted to produce an undo. Selections and marks can be
+mapped over a transaction to translate to a position in the new text state after
+applying the transaction.
+
+> NOTE: `Transaction::change`/`Transaction::change_by_selection` is the main
+> interface used to generate text edits.
+
+`Syntax` is the interface used to interact with tree-sitter ASTs for syntax
+highling and other features.
+
+## View
+
+The `view` layer was supposed to be a frontend-agnostic imperative library that
+would build on top of `core` to provide the common editor logic. Currently it's
+tied to the terminal UI.
+
+A `Document` ties together the `Rope`, `Selection`(s), `Syntax`, document
+`History`, language server (etc.) into a comprehensive representation of an open
+file.
+
+A `View` represents an open split in the UI. It holds the currently open
+document ID and other related state.
+
+> NOTE: Multiple views are able to display the same document, so the document
+> contains selections for each view. To retrieve, `document.selection()` takes
+> a `ViewId`.
+
+The `Editor` holds the global state: all the open documents, a tree
+representation of all the view splits, and a registry of language servers. To
+open or close files, interact with the editor.
+
+## LSP
+
+A language server protocol client.
+
+## Term
+
+The terminal frontend.
+
+The `main` function sets up a new `Application` that runs the event loop.
+
+`commands.rs` is probably the most interesting file. It contains all commands
+(actions tied to keybindings). 
+
+`keymap.rs` links commands to key combinations.
+
+
+## TUI / Term
+
+TODO: document Component and rendering related stuff
-- 
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