aless — a jless-style viewer for every format the tabnas parsers read

MOVING
  j k / ↓ ↑ / C-n C-p / Enter Backspace   down / up one row (count allowed)
  h / ←     collapse an expanded container, else go to the parent
  l / →     expand a collapsed container, else step to the first child
  H         go to the parent without collapsing
  J K       next / previous sibling
  w b       forward / back to the next change in depth
  0 ^ $     first / last sibling
  g G / Home End    first / last row;  Ng NG  go to row N
  C-f C-b / PgDn PgUp   a page down / up
  C-d C-u   half a page down / up (a count sets the distance)
  C-e C-y   scroll one row without leaving the focus behind
  zz zt zb  focused row to the centre / top / bottom
  . , ;     scroll a long value right / left / to its end and back
  < >       less / more indentation

FOLDING
  Space     toggle the focused container
  c C       collapse the focused node and its siblings (C: deeply)
  e E       expand the focused node and its siblings (E: deeply)
  m         switch between data mode and line mode
  %         in line mode, jump between a container's brackets

SEARCH  (regular expressions; smart case; add /s to force case; [ ] { } are literal)
  /pat ?pat   search forward / backward       n N   next / previous match
  * #         search for the focused key forward / backward

COPY AND PRINT  (y copies, p prints to the screen)
  yy pp   pretty-printed value     yv pv   one-line value    ys ps   string contents
  yk pk   key                      yp pP   path .a[0].b      yb pb   ["a"][0]["b"]
  yq pq   jq path

EXPLORER  (aless DIR, or aless alone for the current directory)
  the directory tree uses the same keys: l / Space expand a directory (its
  contents are listed as you go), h collapses, / searches the listed names
  Enter     open the file under the cursor in a new tab (toggle a directory)
  -         go up: the parent directory becomes the root
  :cd DIR   change the root     :explore [DIR]   open another directory tab
  :set hidden | nohidden | hidden!   show dot-files (also --hidden)
  yp        copy the entry's filesystem path

ERRORS
  A file that does not parse shows the parser's report: the message, the
  source lines around the error with a caret under it, and the grammar's
  hint. While a watched file is broken its last good document stays on
  screen with the report docked below it, until the file parses again.
  ! / :error   the active tab's report, full size (after a failed
               :format, that attempt's report); h/l pan a long line

TABS, FILES AND WATCHING
  Tab / Shift-Tab   next / previous tab      :tab N   go to tab N
  :open PATH [FORMAT]   open a file (or a directory) in a new tab (:e is an alias)
  q / :q    close the tab (the last one closed quits)   :qa / :quit   quit
  W / :watch on|off   toggle reloading the tab when its file changes
  r / :reload         reload now (in the program pane, the program)
  s / :source         show the raw source (the focused node's line centred)
  :format FORMAT      parse the tab's text as another format
  :depth N            fold everything below depth N
  :w[!] FILE          write the document as JSON
  :set number | nonumber | relativenumber | norelativenumber | so=N | indent=N
  :N or :line N       go to row N
  F1 / :help          this help

PANES  (aless --panes out[,program], or :vsplit)
  C-w                 move the focus to the next pane; the keys work there
  s                   show the focused pane's text, or its tree again; in the
                      text, : and r work too, and any other key but the
                      scrolling ones shows the tree
  q                   close an output or program pane (the input pane stays)
  :vsplit / :split    side by side / stacked, opening the output beside the input
  :arrange            switch between side by side and stacked
  :pane out|program|close   open the output or the program pane, or close one
  :only               keep the input pane alone
  The output is the document as --render or --alchemy writes it, read
  back as a tree; it is written again when the tab reloads or changes.

  A watched tab reloads when its file changes and keeps your place: the
  focused node is found again by path, or by its nearest surviving
  ancestor and then the node closest to its old source line; folds that
  still exist are kept, and the focus stays on the same screen row.
  Formats: json jsonl jsonic jsonc json5 yaml toml ini csv tsv xml zon
  markdown feed text, and the NAME of any --grammar (by extension or whole
  file name; --kind or :open ... FORMAT to force).