Builtins are chips that link to a glossary generated from the registry, and the virtual filesystem is drawn as a tree

#word draws a builtin as a chip on the tag's ground over a rule (Look and
Exec in acme's look green and exec red), a <code class="word"> in HTML,
and links it to its entry in a new Builtins chapter wherever that
chapter is in the same output (the book, the site). The chapter is
drawn from docs/typ/builtins-tty.json and builtins-gui.json, which
`zig build builtins-json -Dplatform=tty|gui` writes from the registry
and the Help rows (src/builtins_json.zig, tools/gen_builtins_json.zig;
summaryOf in ninep/ctl.zig is now pub); style.typ merges them, marking
the window-only words. The doc steps refresh their build's file first,
and each build's unit-test fails when its file is stale. Everyday words
first (`everyday` in style.typ), then groups by leader prefix as Help
has them, then settings, the words with no path, debugging and
internals, and last an A-Z index of every word. `zig build book` joins
the doc steps.

#fstree draws a directory tree with its connectors, a description
column and links to the sections that document each file; reference.typ
draws the served tree with it, each pane, pty and column file on its
own line, and a test in config.zig checks it against ninep/tree.zig's
files both ways. The cheatsheet has a two-level version. On the site
the tree reads as `tree` text in w3m and wraps descriptions under the
names on a phone.

The site's tutor draws its B1, B2, B3 and 1-2 chords as mouse glyphs;
the landing credits Plan 9 and acme, as does the book's title page;
install.typ no longer lists the mirrors (the footer does).

Co-Authored-By: Claude Opus 5.5 <[email protected]>

1 files changed, 13 insertions, 10 deletions

diff --git a/docs/typ/cheatsheet.typ b/docs/typ/cheatsheet.typ
index c4be1641..3c5ea2b2 100644
--- a/docs/typ/cheatsheet.typ
+++ b/docs/typ/cheatsheet.typ
@@ -2,7 +2,7 @@
 // cheatsheet-a4.typ lays it out; style.typ says how each element looks.
 // config.zig's "docs/typ" test checks every #word, #key and #tag here
 // against the registry, the keymap and the default tags.
-#import "style.typ": key, keys, btn, chord, word, tag, addr, file, cmd, doc, pairs
+#import "style.typ": key, keys, btn, chord, word, tag, addr, file, cmd, doc, pairs, fstree
 
 == The mouse
 #pairs(
@@ -134,15 +134,18 @@ Helix-style: motions *select*, then an edit acts on the selection. Mode box: bla
 Pane shells get `$PARDES_9P` (the socket) and `$PARDES_PANE` (their own pane); a command clicked in a pane also gets `$winid`, the pane it was clicked in.
 #cmd("9ns --mntgen   # then m=$PARDES_MOUNT in every pane")
 #cmd("9p -a \"unix!$PARDES_9P\" read index")
-#pairs(
-  file("index"), [a line per pane: serial, kind, name],
-  file("look exec"), [write a line: a #btn("B3") or #btn("B2")],
-  file("log"), [events; write `follow` to wait],
-  file("pane/new"), [open to make a pane],
-  file("pane/N/addr"), [an address; `data` reads/replaces it],
-  file("pane/N/ctl"), [builtins: #word("Save"), #word("Edit") `...`],
-  file("pane/N/body tag"), [its text (`>>` appends)],
-)
+#fstree(```
+index       a line per pane                         @rules
+look        write: a right click                    @look-and-exec
+exec        write: a middle click                   @look-and-exec
+log         events; follow waits                    @log
+pane/
+  new       open: a new pane                        @panes
+  <n>/
+    addr    where data reads, writes                @addresses
+    ctl     builtins: #word("Save"), #word("Edit")  @panes
+    body    its text (>> appends)                   @panes
+```)
 #cmd("echo notes.txt:12 > $m/pane/$n/look")
 #cmd("echo /foo/ > $m/pane/$n/addr; printf bar > $m/pane/$n/data")
 #cmd("echo 'Edit ,x/foo/c/bar/' > $m/pane/$n/ctl")