Helix

Crate	Description
helix-core	Core editing primitives, functional.
helix-syntax	Tree-sitter grammars
helix-view	UI abstractions for use in backends, imperative shell.
helix-term	Terminal UI

• server-client architecture via gRPC, UI separate from core
• multi cursor based editing and slicing
• WASM based plugins (builtin LSP & fuzzy file finder)
• piece table-based tree structure for changes

Structure similar to codemirror:

text (ropes)

• column utils, stuff like tab aware (row, col) -> char pos translation
• word/grapheme/code point utils and iterators state
• transactions
  • changes
  • 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)
• renders via termwiz
• 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
• invert changes (generates a revert) (collab mode) gutter (line numbers, diagnostic marker, etc) -> ties into UI components rangeset/span -> mappable over changes (can be a marker primitive?) syntax (treesitter)
• indentation strategies 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? pcre) 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)

TODO: determine rust vs script portions

vim stuff: motions/operators/text objects full visual mode macros jump lists marks yank/paste conceal for markdown markers, etc

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codemirror uses offsets exclusively with Line being computed when necessary (with start/end extents) lines are temporarily cached in a lineCache