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cumulus/DESIGN.md
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skkeyeandClaude Opus 5.5 ebe8a5988e Add connect mode, portals, backlinks and renames (stage 8d, v1)
Part 8d, the last of stage 8, and with it everything on DESIGN.md's v1
list.

Connect mode (C): the cursor goes to another node, a dashed arrow in the
visual color follows it, and Enter links the two; then the cursor goes
back to where C was typed (the user's pick). d removes the line between
them (a branch is cut, and the child comes loose), > puts the node under
the other one, and <Space> a, l, c, s and t style the line as you watch,
making it when it isn't there yet. Everything connect mode changes is one
undo group, and Esc takes it back with History::cancel, which leaves
nothing to redo. From visual mode every selected node connects, and the
line pickers go back to connect mode when they close.

Portals show their document live, from a cache of what each document
file holds (open documents from their buffers, the others from their
files, looked at every second): the root's title, its color and how many
nodes it has, or ? when the document isn't there. Enter or gf goes
through, as a jump, and the pane's breadcrumb starts with the documents
it came through. <Space>p types :portal (the user's pick): a path as :e
takes it, or the title of a new document. Backlinks are put right
whenever a document is opened or saved; the root shows how many, the
Note view lists them, gu goes up to them (the user's pick) and
:backlinks lists them.

File names follow the root's title: when it changed, the next save
renames the file (-2 when the name is taken; a folder's default document
keeps its name), and the portals pointing at it, its backlinks in the
documents it leads to, the recent documents, the capital marks and the
jump lists follow. A portal whose file was moved by hand finds its
document in that folder by uid. Portals in a register keep full paths,
so a pasted portal leads to the same document from any folder.

Co-Authored-By: Claude Opus 5.5 <[email protected]>
2026-10-02 08:24:43 -04:00

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# cumulus: design
This is the design approved on 2026-10-01, after six rounds of questions. It's
the reference while cumulus is being built: when a decision changes, this file
changes with it.
## What cumulus is
A keyboard-driven brainstorming app for the terminal, in Rust with ratatui. The
aim is "the idea node graph to end them all": quick idea dumps, mind maps,
whiteboard-style planning and linked notes, in one tool. It runs on Windows and
Linux, with vim keys first and full mouse support.
## Scope
**v1**
- The canvas: nodes, branches, cross-links with every style, folding and focus,
zoom, the `K` card, the mouse.
- The Outline and Note views, splits and the document bar.
- The key engine: medium vim, which-key, help and status-bar hints.
- Visual, move and connect modes; text editing with vim normal mode.
- The command line, with completion and history.
- Portals, with the jump list, backlinks and breadcrumb.
- Rapid entry and the Inbox.
- RON documents with autosave, reload, backups and undo; file names that follow
the root's title.
- The startup rules and `cumulus new`.
- TOML config, key and theme files, with named styles and styles set by tags.
**v1.1**: the Board view · the Search picker across documents · `:tidy` and
align · branch out · export (Markdown, plain text) and import (indented lists).
**Later**: peeking into portals and pulling a document back in · branches that
keep themselves tidy · the Links map · backlinks inside a document · picking
single nodes in visual mode with keys (Ctrl+click does it with the mouse) ·
`Alt+hjkl` · opening a body in `$EDITOR` ·
persistent undo · sessions · operator + motion and macros · a tutorial
document · checkbox, link and date fields · Graphviz and Mermaid export · a
Settings view · vim tab pages.
**Not planned unless asked**: `f` hint jumps · a minimap · straight (braille)
lines.
## Decisions
**Documents and structure**
- Each document has one main root, and the document's name is the root's
title. Loose top-level nodes float around it.
- A tree plus cross-links: each node has at most one parent, and cross-links
join any two nodes, at most one link per pair.
- A node holds a title (one line, never empty), a body, tags and a color. A new
node left empty disappears.
- A portal node shows another document's root, live (its title, color and node
count), and leads there. Portals always land on the root.
- Backlinks are stored in the target document and synced on save, so they
travel with the files.
- Files live anywhere: there's no workspace folder. Portal paths are relative,
with `/` on every OS.
- Each file carries a random `uid`, so "where you left off" survives renames and
a portal can tell when its file was replaced by another document.
- File names follow the root's title, and a rename fixes the portals pointing
at the file. A folder's default document keeps its name (`ideas.cum`).
**Canvas**
- Free placement: a new node appears next to its parent, and nothing moves
unless you move it. Moving a node brings its branch along.
- Folding: each branch is Open, Auto (open while the cursor is inside) or
Closed (a jump inside opens it until you leave). New branches start Open; a
focus toggle makes Open branches act like Auto.
- Zoom levels: Normal (boxes), Far (one line per node: the same width, half
the height) and Overview (colored dots: a quarter of the width, a third of
the height). Far keeps the width because one-line titles collided when
distances were halved both ways (changed during stage 2). Body text never
shows on the canvas: `K` pops it up, and the Note view shows all of it.
- Right-angle lines with proper junctions (`├ ┬ ┼`); lines pass under nodes.
- A node's color goes on its border. Each node can pick its border, and the
theme's named styles and tag rules can set color and border together.
- Connections can set arrowheads (off, end, start, both), a line (solid,
dashed, dotted, thick, double), a color (a palette color or the node's own)
and a label, or use a named style. Branches start solid without arrowheads,
in their parent's color, so a node's color flows down the lines to its
children (dim when the parent has no color). Cross-links start as dim
dashed arrows.
**Keys**
- Medium vim: counts, operators with node targets, registers (with `"+` for the
system clipboard), marks (capital marks across documents), `.` to repeat.
- Tab and `Ctrl-i` jump forward, as in vim, so `a` adds a child.
- `dd` deletes a node with its branch; `x` deletes just the node, and its
children move up.
- A count on `dd`, `yy`, `>>` or `<<` takes in the next siblings: `3dd`
deletes this node and the next two, with their branches, as vim's `3dd`
takes three lines. Which-key says how many as you type (`2d3`: 6 nodes).
- Rapid entry is what happens after `o`, `O` or `a`: Enter starts the next
sibling, Tab / Shift-Tab indent and outdent the idea being typed, and Enter
on an empty idea stops (the empty idea goes away). Esc switches to vim keys
inside the text; a second Esc leaves. Inside a title, `o` and `O` start a
new sibling too.
- `>>` puts the node under the one above it, as its last child; `<<` takes it
out a level, right after its old parent. Both place the node below its new
neighbors, and keep its branch with it.
- `C` (connect mode) edits the connection to another node. Aimed at your own
parent, it styles or cuts the branch line; cutting makes the node loose.
- `M` (move mode) moves the branch; `M` again switches to just the node.
- `gh gj gk gl` move through the tree in every view; plain `hjkl` follow each
view's layout (on the canvas: the nearest node that way).
- Folds: `za zo zc zR zM`, plus `zf` (Auto) and `zi` (focus).
- `q` stays free for macros; quit with `:q`, `:qa` or `ZZ`.
- Which-key works like skyshift's; the leader menu pops up at once. The status
bar shows key hints, and `?` opens searchable help.
- Keys can be changed in `keys.toml`, in vim notation.
**Editing text** (settled in stage 6)
- A title is typed right in its box on the canvas (zoomed to Normal while it's
edited). The box grows with the text, the terminal's cursor sits in it, and
the border takes the insert color while you type.
- The cursor's shape follows the mode, as in vim: a bar while typing (and in
the command line), a block on the letter with vim keys, and the terminal's
own shape elsewhere.
- The document follows the text as you type, so every view stays current. The
whole edit is one undo step (in rapid entry, one per idea); inside the text,
`u` and `Ctrl-r` undo and redo the edit's own changes.
- A title left empty comes back as it was, with a note saying so; a new idea
left empty goes away.
- Registers are shared by the whole app, as in vim: text yanked in one title
pastes into another. `"+` is the system clipboard (part 8c).
- `.` inside the text repeats the last change there, typing included.
- As in vim: `cw` changes to the end of the word, `dw` stops at the end of the
line, `j` and `k` move by lines of text rather than wrapped rows, Esc steps
back onto the last letter typed.
- Tab and Shift-Tab only move a new idea; on an existing title they say that
`>>` and `<<` do it.
- The mouse while editing: a click in the text moves the text cursor; a click
anywhere else keeps the text, finishes the edit and does what a click does; a
double-click on a title starts editing at that letter.
- A portal's title is its document's name, so it isn't edited in place: rename
that document instead.
- Bodies are edited in the Note view and in the `K` card, with the same
editor: Enter starts a new line, Tab types four spaces. `cc`, `C` and `s`
start typing on an empty line too, as in vim (bodies are often empty).
**The rest of vim** (settled in part 8c)
- Visual mode takes in what lies between where it started and the cursor:
on the canvas, every node on show that the rectangle from one end's box to
the other's touches; in the outline and the Note view, the nodes in
between in reading order. `V` takes each with its whole branch; `v` in a
`V` selection (and `V` in a `v` one) switches, and the same key again
stops. Ctrl+click adds or takes out one node; Ctrl+drag on empty canvas
adds every node its rectangle touches. The selection is drawn thick in
the theme's visual color, and the status bar counts it.
- Operators take exactly what's selected (the user's pick): `d` deletes the
selected nodes, and with `v` their unselected children move up, as with
`x`; `y` yanks them with their shape among them; `>` and `<` move nodes
that share a parent; `M` moves them on the canvas (with their branches, or
just them after `M` again); the pickers set every one of them, as one undo
step.
- A register holds text or nodes, and either pastes anywhere: nodes pasted
into a text give their titles, text pasted on nodes becomes nodes. `yy`,
`yab`, `yib` yank nodes; every delete (`dd`, `x`, `dib`, `d` on a
selection) keeps what it took, so `dd` then `p` moves a branch. `p`
pastes as the node's last children and `P` as its next siblings (the
user's pick after trying part 8c: `p` goes under the node as `a` adds,
`P` below it as `o` adds), keeping the yanked layout, where a new node
would go; a count pastes copies. Links between
the pasted nodes come along, and so do links to nodes still there when
they go back into the document they came from.
- `"+` is the system clipboard. Nodes go there as Markdown, the user's
format: a heading per node (`##` for the nodes yanked, `###` for their
children, `####` for anything deeper), its tags as a list between two
`---` lines, then its body. While the clipboard still holds what cumulus
put there, `"+p` gives back everything (colors, bodies, links, the
layout); text from elsewhere becomes nodes (Markdown headings, or a node
per line nested by its indent). `clipboard = "unnamedplus"` makes every
yank, delete and paste use the clipboard, as vim's setting does.
- `.` repeats the last change made with keys in normal or visual mode: the
command with its count and register, plus everything typed in the text
edit it started (`aMulch` then Esc adds another Mulch). A value picked in a
picker repeats on the cursor's node. A change made on a selection repeats
on the cursor's node (`d` as `x`, or `dd` after `V`; `>` as `>>`).
- `/` opens a search in the middle of the screen, as Telescope does (the
user's pick): what's typed at the top, the matches below it, fuzzy, best
first (titles before tags before bodies), with the letters that matched
standing out, and the note of the match you're on beside them. Case only
matters once there's a capital (smartcase). Enter goes there, Esc goes
back; `n` and `N` then go through the same matches, going round, and
`:find` searches straight away.
- Each pane keeps a jump list, as vim's windows do: `gg`, `G`, marks, a
search, `gd`, a link followed in the Note view and switching documents are
jumps. `Ctrl-o` goes back (into another document, opened again if it was
closed), `Ctrl-i` or Tab forward. `''` still goes back to before the last
jump.
- Capital marks (`mA`, `'A`) lead into any document, opening it if it isn't
open; they're kept in the data folder's `memory.ron`, and the small ones
(`ma`) are kept there with each document, so both last from one run to
the next.
- `gd` follows the cursor's cross-link; with several, a list of them pops up
beside the node. `:marks`, `:jumps` and `:registers` list them; Enter goes
to the mark or the place, or pastes the register.
**Connect mode and portals** (settled in part 8d)
- `C` starts connect mode on the cursor's node: the cursor goes to another
node as usual (`hjkl`, `gh`…, `n` after a search, a click), the node
being connected is drawn thick in the visual color, and a dashed arrow in
that color follows the cursor. Enter links them (a line already there
stays) and connect mode is done, with the cursor back on the node `C`
started from (the user's pick). `d` removes the line between them: a link
goes; a branch (aimed at the node's parent, or at a child) is cut, and the
child comes loose with its own branch. `>` puts the node under the one
aimed at, as its last child, where it is on the canvas (a link between the
two goes: the branch takes its place).
- The `<Space>` keys style the line as you watch: `a` and `l` go through the
arrowheads (off, end, start, both) and the kinds of line (solid, dashed,
dotted, thick, double); `c` and `s` pick a color (or the node's own) and a
named line style; `t` a link's label, where typing a label that isn't
listed makes it. A line that isn't there yet is made, as a link. Everything
connect mode changes is one undo step, and Esc takes it all back.
- From visual mode, `C` connects every selected node (with `V`, each
branch's top) to the one the cursor goes to. Connect mode works in every
view, and stays in its document.
- A portal shows its document live: the root's title, its color (when the
portal has none of its own) and how many nodes it has, in the box's corner
(`?` and faded when the document isn't there). The portal remembers the
title, in case the file goes. Enter or `gf` goes through it, to the root:
a jump, so `Ctrl-o` comes back. The breadcrumb then starts with the
documents the pane came through (`Garden plans » Kitchen › Herbs`);
going back up one of them takes the trail back there.
- `<Space>p` opens the command line with `:portal ` typed (the user's
pick): a path as `:e` takes it, relative to the document's folder, with
the same completion. An existing document gets a portal under the
cursor's node, where `a` adds a child; when nothing's there, what was
typed is a new document's title, made next to this one as `:new` makes
it. A portal to its own document, or to a file that isn't a document, is
refused.
- Backlinks are put right whenever a document is opened or saved: each
document its portals lead to gets exactly one backlink per portal (an
open one in its buffer, written at once unless it has changes of its own
to save with them; a closed one in its file, unless another cumulus has
it). The root shows how many (`« 2`), the Note view lists them on the
root, and `gu` goes up to them (the user's pick): one straight there, on
the portal, several in a list, the document the pane came from first.
`:backlinks` always lists them.
- File names follow the root's title: when the title changed since the
file was read or written, the next save renames it (`-2`, `-3`… when the
name is taken; a folder's default document keeps its name). The portals
pointing at it take the new path (in the documents its backlinks name,
and any open one), as do the backlinks in the documents it leads to, the
recent documents, the capital marks and the jump lists.
- A portal whose file isn't where it says looks in that folder for its
document by uid (a file moved or renamed by hand), and keeps the path it
finds.
**Views, panes and popups** (settled in stage 7)
- The Note view is made of parts: the title, the tags, the body, each link
(out, then in) and each child. `j` and `k` step through them, with a bar
marking the one you're on; Enter, `i` or `A` edits it (`I` from its start,
`cc` `S` anew), or goes to that link (a jump: `''` comes back) or child.
`h` and `l` turn the page: the sibling before or after. Node keys (`dd`,
`za`, `o`…) act on the note's node. The note follows the cursor, starting
at the title of each node it comes to.
- The outline has a row per node: its fold marker (`▾` `▸`), tree lines in
the parent's color (as branches are on the canvas), its tags, `¶` when it
has a body, `+N` for what a fold hides. `zb` shows every body under its
title, where its children hang, to read the document like a page. `j` and
`k` go row by row, `h` and `l` to the parent and the first child; a click
on a marker folds. Titles are edited in their row, rapid entry included.
Rows wider than the view scroll sideways (`zh` `zl`, the wheel sideways),
and the cursor's title comes back into view when the cursor moves.
- Move mode in the outline and the Note view moves the node through the
tree: `j` and `k` swap it with its siblings (`J` and `K` five places), `h`
takes it out a level, `l` puts it under the one above.
- The status bar has two lines: the mode, the view, the breadcrumb (or a
message in its place) and the keys typed so far; then the key hints for
what you're doing. `<Space>w` hides the hint line along with which-key.
- Help (`?`, `<Space>?`, `:help [topic]`) lists every key of the focused view
and every `:` command, under which-key's headings. `/` searches (rows that
start with what's typed first, then fuzzy matches), and Enter runs the row:
a key that waits for more (`m`) is typed for you to finish, and a `:`
command that needs an argument opens the command line with it typed.
- The `K` card opens beside the node (in the middle when the node isn't on
screen). `j` `k` `Ctrl-d` `Ctrl-u` scroll it; `i`, `A` or Enter edits the
body right there (`I` from its start), and when that's done the card stays;
`K`, `q` or Esc closes it.
- Right-click opens a menu of what you can do with the node, each with the
keys that do the same; on the empty canvas: a new idea right there (a loose
node), zoom in and out. `<Space>c` `<Space>B` `<Space>s` `<Space>t` open
the color, border, style and tags pickers, which start on what the node has
now. In the tags picker Enter puts a tag on or off and the picker stays
open; a search that matches no tag, then Enter, adds it as a new one.
- Every pane has a box with its view and document in the top border, the
focused one in the accent color. A new pane comes first (left or above)
and takes the focus, as in vim, and closing the last pane quits (`q`,
`ZZ`, `:q`). A click focuses the pane under it; a text edited in the old
one is done first.
- The document bar is always at the top, the focused pane's document
standing out; a click on a name shows that document in the pane. Each pane
can show any open document.
- Popups (the help, the menu, the pickers, the card) are a mode of their own:
keys and clicks go to them, a click outside a list closes it, and they stay
above the status bar.
**Files and saving** (settled in part 8a)
- Documents are RON files ending in `.cum`. Configs are TOML: `config.toml`,
`keys.toml` and `themes/<name>.toml`.
- Autosave a second after the latest change, so typing isn't saved letter
by letter (`autosave = false` for vim-style `:w`). Undoing back to what's
on disk counts as no change. The document bar marks unsaved changes `[+]`.
Quitting saves first; without autosave, `:q` with unsaved changes refuses
(`:q!` drops them), and `ZZ` saves, then closes, as in vim.
- Every second, cumulus looks at each file's time and size. A file changed
outside cumulus is read again as an undo step (`u` brings back what was on
screen); never under a text being edited or a node being moved, which it
waits for. If you also had unsaved changes, cumulus asks which to keep
(Esc: later; `:w` keeps yours, `:e!` takes the file's). A file with a
mistake in it (a hand edit half done) stops autosave until it's fixed or
`:w` saves over it; a deleted or moved file waits for `:w` to write it
again.
- The day's first save copies the file to the data folder's backups first
(`backups/<uid>/2026-10-01.cum`, the last 30 days kept).
- A document open in another cumulus opens read-only (`[RO]` in the bar)
until that one lets go of it. The lock is the operating system's lock on
a file in the data folder, so a crash never leaves one behind.
- Undo per document, while cumulus runs: one step per command, per
text-editing session, and per node in rapid entry.
- Each document reopens where you left it: the cursor, and the canvas's
zoom and scroll. The documents picker (`<Space>b`) lists the documents
opened lately after the open ones.
**Screen**
- Vim-style splits; panes on the same document share one cursor.
- Open documents are buffers, listed in a bar at the top; the status bar is at
the bottom.
**Project**
- A library plus a thin `main.rs`, so build stages can run as examples.
- Rust pinned to 1.90.0; nothing needs nightly.
## Data model (`model/`: pure data, no UI, no files)
```rust
// Ids and units: newtypes, so they can't be mixed up.
NodeId(u32) // unique inside a document, never reused while it's open
BufferId(u32) // an open document, like vim's buffer numbers (:ls, :b 3)
PaneId(u32) // a split
DocUid(u64) // stored in the file, survives renames
CanvasPos { x: i32, y: i32 } // cells at Normal zoom, may be negative
ScreenPos { col: u16, row: u16 } // a terminal cell
Camera { origin: CanvasPos, zoom: Zoom } // converts between the two
enum Zoom { Normal, Far, Overview }
// Text, checked once when it comes in.
Title // one line, never empty
Body // any text
Tag // lowercase, no spaces, stored without '#'
Label // a connection label: one short line
ColorName, StyleName // names looked up in the theme
// A node and its place in the tree.
struct Node { content: Content, tags: Tags, look: NodeLook, pos: CanvasPos, fold: Fold }
enum Content { Idea(Idea), Portal(Portal) }
enum Fold { Open, Auto, Closed }
enum Place { Root, Loose, Child { parent: NodeId, branch: LineLook } }
struct NodeLook { color: Option<ColorName>, border: Option<Border>, style: Option<StyleName> }
enum Border { Rounded, Square, Double, Thick, Dashed, Hidden }
// Cross-links. Branch lines use the same LineLook.
struct Link { from: NodeId, to: NodeId, label: Option<Label>, look: LineLook }
struct LineLook { arrows: Option<Arrows>, line: Option<Stroke>, color: Option<LineColor>, style: Option<StyleName> }
enum Arrows { Off, End, Start, Both }
enum Stroke { Solid, Dashed, Dotted, Thick, Double }
enum LineColor { Named(ColorName), FollowNode }
// Between documents.
struct Portal { path: LinkPath, uid: DocUid, title: Title } // title: kept in case the file goes missing
struct Backlink { from: LinkPath, uid: DocUid, node: NodeId }
// The document. Its fields are private, so only its methods can change it.
struct Document { uid, root: NodeId, entries: BTreeMap<NodeId, Entry>, loose: Vec<NodeId>,
links: BTreeMap<LinkKey, Link>, backlinks: Vec<Backlink>, next_id }
struct Entry { node: Node, place: Place, children: Vec<NodeId> }
```
The `Option` fields in `NodeLook` and `LineLook` are overrides. A look is built
up in layers: the theme default, then the tag style, then the named style, then
the node's own fields. Each layer only states what it changes.
**Rules the `Document` methods guarantee**
- There is exactly one root, and it can't be deleted or given a parent.
- Each node has at most one parent, and there are no cycles: a move checks
ancestors first.
- Children keep their order, and the file lists nodes in outline order.
- A link never joins a node to itself, both of its ends always exist, and
deleting a node removes its links.
**Undo.** Every change runs as a transaction:
`doc.edit(|e| { e.add(…)?; e.update(…)?; Ok(()) })`. The transaction records
the old value of everything it touches. If a step fails, it rolls back; if it
succeeds, that record becomes one undo step. Undo writes the old values back,
redo the new ones. No command needs its own "reverse" code, and the records are
plain data, ready for a persistent undo file later.
**Folding** is one pure function of the document, the cursor and the focus
toggle, so every view folds the same way.
**Portals.** A cache holds each target's root title, color and node count,
refreshed when files change. When a root's title changes, the next save renames
the file, then fixes the portal paths in every document listed in its
backlinks, and the backlink paths in every document it points to.
## Screen and views
```
cumulus Garden plans [+] │ Kitchen │ Reading list
┌ Outline ──────────────┐┌ Canvas ───────────────────────────────────────────┐
│ ▾ Garden plans ││ ┌──────┐ │
│ ├ Soil ││ ┌──┤ Soil │ │
│ ├ [Raised beds] ││ │ └──────┘ │
│ │ └ Cedar ││ ╭──────────────╮ │ ┏━━━━━━━━━━━━━┓ ┌───────┐ │
│ └ Watering ││ │ Garden plans ├──┼──┨ Raised beds ┠────┤ Cedar │ │
│ ◦ ask about compost ││ ╰──────────────╯ │ ┗━━━━━━━━━━━━━┛ └───────┘ │
│ ││ │ ┌──────────┐ │
│ ││ └──┤ Watering │ │
│ ││ └──────────┘ │
└───────────────────────┘└───────────────────────────────────────────────────┘
NORMAL │ Canvas │ Garden plans › Raised beds 2g
```
| View | What it's for |
|---|---|
| **Canvas** | The 2D map: free placement, 3 zoom levels, right-angle lines and the mouse. |
| **Outline** | Reorganizing and reading: an indented tree with fold markers, `+N` for hidden nodes and `»` for portals, with loose nodes listed at the end. |
| **Note** | Writing: one node's title, tags, color and body (with vim motions inside), plus its links in and out and its children. It follows the cursor. |
| **Board** (v1.1) | Sorting: columns by tag or color. Moving a card to another column changes its tag. |
- **Pickers:** documents, colors, borders, styles and tags in v1; Search in v1.1.
- **Popups:** which-key (bottom right, as in skyshift), `?` help, the `K` card,
the right-click menu, confirmations, and the command line with its
completion list.
- **Top bar:** the open documents. **Bottom bar:** the mode, the view, the
breadcrumb (or a message), and the keys typed so far (`2g` above); then a
line of key hints, which `<Space>w` hides.
**Mouse** (on the canvas; other views get click, double-click and scroll):
click selects, double-click edits the title (from the letter clicked),
dragging a node moves it with its branch, dragging empty space pans, the wheel
pans up and down, and sideways with a wheel that tilts, a touchpad, or the
wheel with Shift or Alt held (Alt for terminals that keep Shift for selecting
text), Ctrl+drag selects a rectangle, Ctrl+click adds or removes one node,
right-click opens a menu built from the same actions as the keys. Zoom is on
the `+` and `-` keys.
## Modes and keys
```rust
enum Mode {
Normal,
Text(TextEdit), // a title or body being edited: typing (INSERT) or vim
// keys inside it (TEXT); the editor knows which, so the
// two can't disagree. Rapid entry lives here too.
Visual(Visual), // anchor + Rectangle or Branches
Move(Grab), // a node or a branch being moved
Connect(Connect), // the nodes being connected, where the cursor goes
// back, and the undo group Esc takes back
Command(CommandLine), // `:` with completion
Popup(Popup), // the help, the menu, a picker or the K card (which
// holds its own TextEdit while the body is edited)
}
```
Each mode has its own key tables. Which-key, `?` help and `keys.toml` all read
those same tables. The engine handles counts, registers, operator + target
(`d` + `ab`), and keys that take a character after them (`ma`, `fx` inside
text).
| Group | Keys |
|---|---|
| **Move** (every view) | `hjkl` or arrows · `gh gj gk gl` tree moves · `w` `b` next / previous in reading order · `gg` root · `G` last · `/` `n` `N` search · `Ctrl-o` `Ctrl-i` (Tab) jump back / forward · `m{a-z}` `'{a-z}` marks (`A–Z` across documents) · Enter or `gf` through a portal · `gu` up to the portals that lead here · `gd` follow a cross-link |
| **View** | `zz` center · `Ctrl-e` `Ctrl-y` `zh` `zl` pan · `Ctrl-d` `Ctrl-u` half a screen · `+` `-` zoom · `za zo zc zR zM` folds · `zf` Auto · `zi` focus · `K` body card |
| **Create and edit** | `o` `O` sibling below / above · `a` child · `i` `A` Enter edit the title · `I` edit from its start · `cc` `S` retype |
| **Operators** | `dd` or `dab` delete branch · `dib` delete children · `x` delete just the node · `yy` `yab` `yib` yank · `p` paste as children · `P` paste as siblings below · `>>` `<<` indent / outdent · `"a`–`"z` and `"+` registers · `.` repeat · `u` `Ctrl-r` undo / redo |
| **Modes** | `v` `V` visual · `M` move · `C` connect · `:` command · Esc back to normal |
| **Leader** `<Space>` | `c` color · `s` style · `B` border · `t` tags · `p` new portal (`:portal `) · `i` inbox · `b` documents · `v` then `c`/`o`/`n` for canvas / outline / note · `w` which-key on/off · `?` help |
| **Panes, documents** | `Ctrl-w v` `Ctrl-w s` split · `Ctrl-w hjkl` focus · `Ctrl-w w` the next pane · `Ctrl-w c` close · `Ctrl-w o` only · `Ctrl-w =` even sizes · `gt` `gT` `]b` `[b` next / previous document · `ZZ` close pane (the last one quits) |
| **Outline** | `j` `k` rows · `h` `l` parent / first child · `zb` every body · `M` then `j` `k` (`J` `K`: 5) swap with siblings, `h` out, `l` under the one above |
| **Note view** | `j` `k` parts · Enter `i` `A` edit the part (`I` from its start, `cc` `S` anew), or go to that link or child · `h` `l` the sibling before / after |
| **Lists** (help, menu, pickers) | `j` `k` `gg` `G` `Ctrl-d` `Ctrl-u` move · `/` search · Enter pick or run · Esc or `q` close |
| **K card** | `j` `k` `Ctrl-d` `Ctrl-u` scroll · `i` `A` Enter edit the body (`I` from its start) · `K` `q` Esc close |
| **Typing** | `Backspace` `Delete` · `Ctrl-w` delete word · `Ctrl-u` delete line · arrows, Home, End · Enter (title: done, or after `o O a` the next idea; body: new line) · Tab Shift-Tab (a new idea: under the one above / out a level) · Esc to vim keys |
| **Inside text** | `h j k l w b e 0 ^ $ gg G` (and arrows, Home, End) · `f t F T ; ,` · `d` `c` `y` with any motion and `iw aw i" a" i( a(` · `x X s S D C Y` · `r ~ J p P` · `u Ctrl-r .` · `i a I A` back to typing · `o O` (title: a new sibling; body: a new line) · Esc done |
| **Move mode** | `hjkl` 1 cell · `HJKL` 5 cells · `M` branch ↔ node · Enter or Esc done |
| **Connect mode** | move to the target as usual (or click it) · Enter link · `d` remove (a branch: cut) · `>` attach as child · `<Space>` style menu (`s` named, `a` arrows, `l` line, `c` color, `t` label) · Esc cancel (takes it all back) |
| **Visual** | `d` `x` `y` `>` `<` `M` and `<Space>c` `<Space>s` `<Space>B` `<Space>t` act on the whole selection · `o` swaps ends · `v` `V` switch, or stop · Ctrl+click, Ctrl+drag pick with the mouse |
## Files
**Documents** (`.cum`, RON). A `backlinks: [...]` list appears once another
document has a portal pointing here.
```ron
// cumulus document. Hand edits are fine: cumulus reloads it when it changes.
(
format: 1,
uid: "7f3c9a1e52b04d18",
root: 1,
nodes: [
(
id: 1,
title: "Garden plans",
pos: (0, 4),
color: "green",
),
(
id: 2,
parent: 1,
title: "Raised beds",
pos: (22, 4),
tags: "#todo",
fold: Auto,
body: "Cedar, three of them.
40 cm high.",
),
(
id: 3,
parent: 1,
portal: (
path: "kitchen.cum",
uid: "c01d5e7aa0f3b912",
title: "Kitchen",
),
pos: (22, 8),
),
(
id: 4,
title: "ask about compost",
pos: (0, 14),
),
],
links: [
(
from: 2,
to: 4,
label: "needs",
line: Dashed,
arrows: End,
),
],
)
```
**Config** (TOML) lives in `%APPDATA%\cumulus\config` (`~/.config/cumulus` on
Linux); `cumulus --paths` prints the folders. Each file only states what it
changes: a missing file changes nothing, and a mistake only drops its own line,
with a message in the status bar saying what's wrong. cumulus applies a file
again when it's saved. (Settled in part 8b.)
- `:config` lists config.toml, keys.toml and the theme's file, with the folder
they're in; Enter opens one in your editor (the `editor` setting, `$VISUAL`,
`$EDITOR`, else notepad on Windows and vi elsewhere), with the terminal
handed over until it's done. A file that isn't there yet is written first,
every option at its default behind a `#`, with what it does: keys.toml lists
every command by name.
- `:set` and `:theme` change things until cumulus quits, as in vim; the files
change them for good.
- A theme file is laid over the built-in theme (`default`): a theme that says
just `accent = "magenta"` is the built-in one in magenta, and
`themes/default.toml` changes the built-in theme itself. Screen colors are
terminal colors; the colors in looks and styles are palette names.
- The built-in theme comes with named styles, each put on by the tag of the
same name: `question` (yellow, dashed), `important` (red, thick) and `done`
(gray, its title faded); and two for links, `blocks` (red, dashed, "blocks")
and `supports` (green, "supports"). The user's pick in part 8b.
```toml
# config.toml
theme = "default" # or a file in the themes folder
default_document = "ideas" # what `cumulus` looks for at startup
autosave = true
mouse = true
which_key = true
which_key_delay = "300ms"
max_node_width = 30
glyphs = "unicode" # "ascii" for fonts without box-drawing characters
completion_popup = "as-you-type" # "on-tab": only after Tab, like vim's wildmenu
editor = "" # what :config opens files in ("nvim", "code --wait")
clipboard = "cumulus" # "unnamedplus": plain y, d and p use the system clipboard
# keys.toml: sections motions, normal, canvas, outline, note, visual, move,
# connect, list, card, text (vim keys inside text), insert (typing: one key each,
# the others type themselves); commands by name; "nothing" unbinds
leader = "<Space>"
[normal]
"<Space>x" = "delete-branch"
"x" = "nothing"
[canvas]
"H" = "previous-document"
# themes/night.toml
accent = "cyan" # screen colors: terminal names, 0-255, or "#rrggbb"
muted = "darkgray"
[modes]
insert = "green"
visual = "magenta"
[palette] # the colors nodes and lines are given, by name
red = 167
orange = 208 # … yellow, green, teal, blue, purple, pink, brown, gray
[node] # every node, unless something says otherwise
border = "square"
[root]
border = "rounded"
[branch] # lines from a parent to its children
line = "solid"
arrows = "off"
color = "node" # the parent's own color
[link] # cross-links
line = "dashed"
arrows = "end"
[styles.node.question] # named node styles: <Space>s, and [tags]
color = "yellow" # a palette color
border = "dashed"
[styles.node.done]
color = "gray"
faded = true # the title in the muted color
[styles.link.blocks] # named line styles, for links
color = "red"
line = "dashed"
arrows = "end"
label = "blocks" # shown on a link without a label of its own
[tags]
question = "question" # a #question node gets the "question" style
```
**Data folder** (`%APPDATA%\cumulus\data`, `~/.local/share/cumulus` on Linux):
`memory.ron` (where you left off in each document, keyed by `uid`, with its
marks; the capital marks; the command history; recent documents), `backups/`
and `locks/`. If a second cumulus opens a document that's already open, it
opens it read-only.
**Command line**
- `cumulus` opens `./ideas.cum`, or `~/ideas.cum` if the current folder doesn't
have one. When neither exists, it starts a new `~/ideas.cum` (written once
something is added): one ideas document for everywhere (the user's pick in
part 8a).
- `cumulus garden.cum` opens that file (a new document if there's no such
file yet, as `:e` does); `cumulus some/folder` opens that folder's default
document. Several can be named; the first one shows.
- `cumulus new` creates `./ideas.cum`, and `cumulus new "Garden plans"` creates
`./garden-plans.cum`. If the file already exists, cumulus opens it and says so.
- `cumulus --paths`, `--version` and `--help`.
## Module layout and flow
```
cumulus/
├─ Cargo.toml rust-toolchain.toml build.rs rustfmt.toml .cargo/config.toml
├─ README.md DESIGN.md .gitignore .gitattributes
├─ examples/ the playground: cumulus on copies of two sample documents (canvas.rs)
└─ src/
├─ main.rs command-line arguments, then app::run
├─ lib.rs the module list
├─ model/ ids, text, geometry, look, node, portal, link, document, edit, op (edits as
│ data), history, fold, clip (nodes taken out, to paste)
├─ input/ key (vim notation), command (Command enum + names), bindings (default tables),
│ keymap (+ keys.toml), engine (counts, registers, operators), mouse
├─ command/ registry, parse, complete, history
├─ view/ mod.rs (the View trait), canvas/ (camera, boxes, lines, route, scene, render,
│ navigate, placement, view), outline, note; later board
├─ ui/ text_input (a line of text and its cursor), text_editor/ (vim inside text:
│ motion, object, layout), list (the popup list help, menus and pickers
│ share), card (the K card), status_bar, document_bar, which_key,
│ command_line, theme, glyphs
├─ config/ paths (the config and data folders), settings (config.toml, `:set`), keys_file
│ (keys.toml's template), theme_file (themes laid over the built-in one)
├─ storage/ document_file (RON), write_atomically, names (file names from titles), link_paths
│ (portal paths: relative, with /), backup, lock, stamp (noticing changes made
│ outside), memory (memory.ron), markdown (nodes as Markdown, for the clipboard)
└─ app/ mod.rs (App), input (keys and the mouse, routed), update (carrying actions out),
render, terminal (the main loop, setup, teardown, panic hook), startup (what
`cumulus` opens), documents (the open documents and their files), files
(saving, reloading, locks, where you left off), configure (settings, keys and
themes applied; `:config`), action, mode, buffer, commands
(keys every view shares), calls (`:` commands), text_edit (a node's text being
edited, rapid entry), registers (text or nodes), clipboard (the system's, for
"+), yank (nodes into registers and back), visual (selections), repeat (`.`),
search (`/`), jumps (each pane's jump list), marks (capital marks, `:marks`),
connect (connect mode), portals (what portals show, going through them,
`:portal`, backlinks, renames), panes (the split tree), popup (help, menu,
pickers, card, questions)
```
The end-to-end tests are in `app/tests.rs` (with `app/tests/files.rs`,
`app/tests/config.rs`, `app/tests/vim.rs`, `app/tests/connect.rs` and
`app/tests/portals.rs`): they copy the sample
documents to a temporary folder, type keys and click on a test terminal, and
check the screen, the documents and the files.
**Flow:** a terminal event comes in → the key engine turns keys into a typed
`Command` (with its count and register) → the focused view answers it with
`Action`s, and `app::commands::shared` answers the commands the view leaves
(undo, marks, adding, deleting, folds, modes…), so a view can give a key its own
meaning → a `:` line is parsed into a `Call` and `app::calls` answers it →
`update` carries out the actions in order, stopping at the first problem:
document actions go to the document's `Buffer` (the only place a document
changes: the edit, its undo step, the cursor and the marks), the rest change
the mode or the app → the screen is drawn from the state.
While a text is edited, keys go to the edit (`app::text_edit`) instead: when
typing, a key the `insert` table binds is a command (Enter, Tab, Backspace…)
and any other key types itself; with vim keys, the key engine reads the `text`
table, where operators take motions as targets too (`dw`, `c$`, `dfx`). The
edit answers with actions like everything else. While a popup is open
(`app::popup`), keys and clicks go to it the same way: through the `list` or
`card` table, or straight into its search. The help and the menu run what
you pick as if its keys were typed (`AppAction::Run`).
The panes (`app::panes`) are a split tree, apart from what each pane shows:
a view and one of the open documents. Only the focused pane is in the mode
(the others are drawn as in normal mode), and its document is the one the
actions change; a click focuses the pane under it first.
Edits travel as data (`EditOp`), so views never touch the document. A `Group`
makes several edits one undo step: a whole move-mode session, a mouse drag, a
text edit, an idea in rapid entry. A group whose edits cancel out (an idea
added, then left empty) leaves no step at all.
```rust
trait View { // settled in stage 5
fn kind(&self) -> ViewKind;
fn contexts(&self, mode: &Mode) -> &'static [Context]; // its key tables, most specific first
fn layout(&mut self, area: Rect, ctx: &ViewContext); // fit to the area, follow the cursor
fn render(&self, frame: &mut Frame, ctx: &ViewContext); // draws the layout, changes nothing
fn command(&mut self, typed: &Typed, ctx: &ViewContext) -> Option<Vec<Action>>; // None: not mine
fn mouse(&mut self, gesture: Gesture, ctx: &ViewContext) -> Vec<Action>;
// Added in stage 7, with defaults:
fn status(&self) -> String; // its name in the status bar
fn cursor_area(&self, ctx: &ViewContext) -> Option<Rect>; // where the K card goes beside
// Added in part 8a, with defaults (only the canvas has a camera):
fn camera(&self) -> Option<Camera>; // kept with the document
fn set_camera(&mut self, camera: Camera); // where you left off
}
// ViewContext: the document, the cursor, the mode, the theme and the view settings.
```
What changed from the first sketch: `layout` comes before `render`, because a
view keeps the frame it drew (the canvas matches clicks against it) and moves
its camera to follow the cursor, and drawing should change nothing; `command`
takes the whole `Typed` (counts matter) and returns `None` for commands it
leaves to the shared ones.
## Build order
Hardest parts first, so they shape a simple interface that every view shares
and the core ends up thin. The model comes first because every hard part reads
it.
| # | Stage | What you can run |
|---|---|---|
| 0 | Skeleton: Cargo.toml, toolchain, `build.rs`, rustfmt, aliases, README, DESIGN.md | `cumulus --version` |
| 1 | Model: types, document rules, transactions and undo, folding, RON round trip | `cargo test` |
| 2 | Canvas engine: camera, boxes, a line layer with junctions, right-angle routing, arrows and labels, zoom levels, hit-testing, nearest-node moves, placement | `cargo run --example canvas` |
| 3 | Key engine: notation, tables, counts, registers, operator + target, keys that take a character, which-key, `keys.toml` | the example gets real keys and which-key |
| 4 | Command line: registry, parser, completion (popup + ghost text), history | `:` in the example |
| 5 | The shared `View` interface, `Action` and `Mode`, pulled out of stages 2–4 | the example runs through it |
| 6 | Text editor: typing, plus vim normal mode inside text | editing titles in the example |
| 7 | Outline and Note views; splits (the split tree); status bar, document bar, help, `K` card, right-click menu, pickers (documents, colors, borders, styles, tags) | the example with splits and two documents |
| 8a | App core: the main loop, terminal setup and panic hook, buffers and panes (from the example into the app), files (load, autosave, reload, backups, locks, where you left off), the startup rules and `cumulus new`, `:set` | `cumulus` |
| 8b | Settings: config.toml, keys.toml, themes (named styles, styles by tag), `:theme`, `:config` | |
| 8c | The rest of vim: visual mode, node yank and paste with registers (`"+`: the clipboard), `.` on nodes, `/` `n` `N`, the jump list, capital marks, `gd` | |
| 8d | Connect mode, portals, backlinks, file names that follow the root's title | v1 |
| 9 | v1.1: Board, Search picker, `:tidy` and align, branch out, export/import | |
Each stage ends with `cargo build`, `cargo lint` and `cargo test` passing, and
one commit. Stage 8, as big as stages 5 to 7 together, comes in four parts
with a commit each, and a pause after each for the user to try it (their
choice).
## Crates and tooling
- **Crates:** ratatui 0.30 (with the crossterm 0.29 it ships with) · serde, ron
0.12 and toml 1 · directories 6 · thiserror 2 and anyhow · arboard 3 (with
Wayland support) · unicode-width and unicode-segmentation. No testing crates.
Each crate is added in the stage that first needs it.
- **Toolchain:** `rust-toolchain.toml` pins 1.90.0 with clippy, rustfmt and the
musl target.
- **`build.rs`:** embeds the git commit for `cumulus --version`.
- **Windows first:** only key Press and Repeat events count; a panic hook
restores the terminal (raw mode, the screen, the mouse); paths come from
`directories`.
- **Same as skyshift:** edition 2024, rustfmt at 110 columns, `cargo lint` and
`cargo linux`, the static C runtime on Windows, LF line endings, `unsafe`
forbidden.
- **Doc comments** on public types and functions, written where they explain
something. (The `missing_docs` lint was dropped: it demands a comment on
every field and enum variant, which is the comment noise we don't want.)
## Tests
- **Keys:** notation, sequences, counts, registers, operator + target,
overrides, and no binding hiding another.
- **Command line:** parsing, abbreviations, completion ranking, history.
- **Model:** tree rules, undo/redo round trips, folding.
- **Canvas:** camera conversions, routing and junctions (small text snapshots),
hit-testing, nearest-node moves.
- **Text editing:** vim keys inside text driven key by key (motions, operators,
text objects, `.`, undo), rapid entry, empty titles, registers, bodies and
tags.
- **Views:** the outline and the Note view drawn on a test terminal (rows,
parts, drafts being edited), and driven by keys and clicks.
- **Panes and popups:** splitting, closing and moving the focus in the split
tree; lists (moving, searching, clicks), the help, the menu, the pickers and
the card, driven by their key tables.
- **The example:** its tests drive the whole loop on a test terminal, keys and
mouse in and the screen out, so what a stage says works is checked end to
end.
- **Files:** RON round trip, load errors, config parsing, and backlink and
rename fix-ups, in temporary folders.