editors syntax highlighting ...

- emacs syntax: add tree-sitter major mode for SiSU spine markup
  New file sisu-spine-ts-mode.el is a sibling of the existing regex
  mode, backed by Emacs 29+'s built-in treesit.el and the
  tree-sitter-sisu grammar. It replaces the long font-lock keyword list
  with treesit-font-lock-rules grouped into eight features (comment,
  header, heading, block, inline, note, link, index, misc) so users
  can dial verbosity via treesit-font-lock-level. It also wires up:
  - treesit-simple-imenu-settings for a heading outline,
  - treesit-thing-settings for sentence / paragraph motions,
  - treesit-defun-type-regexp so C-M-a / C-M-e jump heading-to-heading,
  - a sisu-spine-ts-install-grammar command that registers
    treesit-language-source-alist and runs
    treesit-install-language-grammar so users can install the parser
    from inside Emacs without leaving the editor.

- the original sisu-spine-mode.el is unchanged and supported for
  Emacs < 29 and for users who prefer regex highlighting.

- nvim drop-in: point parser fetch at tools/tree-sitter-sisu
  sundry/editor-syntax-etc/nvim/
  The nvim-treesitter install_info now fetches the parser from
  https://git.sisudoc.org/projects/tree-sitter-sisu which can be cloned
  via git://git.sisudoc.org/tools/tree-sitter-sisu The fetched paths:
    files = { "src/parser.c", "src/scanner.c" }
  submission of the sisu parser to nvim-treesitter's parsers.lua should
  be a near-trivial one-liner.

- the original vim regex highlighter remains as before
  - sundry/editor-syntax-etc/vim/syntax/sisu-spine.vim
  - sundry/editor-syntax-etc/vim/templates/{sst,ssm,ssi}.tpl
    new skeleton templates for the three SiSU markup file types
    sets up the YAML header (title, creator, date, rights, classify,
    identfier)

- .gitignore - whitelist the new files

(assisted by Claude-Code)

9 files changed, 566 insertions, 0 deletions

diff --git a/sundry/editor-syntax-etc/nvim/README.md b/sundry/editor-syntax-etc/nvim/README.md
new file mode 100644
index 0000000..8e889e7
--- /dev/null
+++ b/sundry/editor-syntax-etc/nvim/README.md
@@ -0,0 +1,87 @@
+# Neovim integration for SiSU spine markup
+
+Tree-sitter-backed syntax highlighting, folding, and structural
+navigation for `.sst` / `.ssm` / `.ssi` files in Neovim (>= 0.9).
+
+## What is in this directory
+
+```
+nvim/
+  ftdetect/sisu.lua        - register .sst/.ssm/.ssi as filetype "sisu"
+  ftplugin/sisu.lua        - per-buffer settings (commentstring, conceal)
+  lua/sisu-spine/init.lua  - entry point: registers parser config
+  queries/sisu/            - tree-sitter queries (mirrors tree-sitter-sisu/queries/)
+    highlights.scm
+    folds.scm
+    injections.scm
+    textobjects.scm
+    indents.scm
+```
+
+## Install (manual)
+
+1. Symlink or copy this directory into your Neovim runtime path:
+
+   ```sh
+   ln -s /path/to/sisudoc-spine/sundry/editor-syntax-etc/nvim \
+         ~/.config/nvim/pack/sisu/start/sisu-spine
+   ```
+
+2. Tell `nvim-treesitter` how to fetch the parser. Add to your config
+   (`init.lua`):
+
+   ```lua
+   require("sisu-spine").setup()
+   require("nvim-treesitter.configs").setup({
+     ensure_installed = { "sisu" },
+     highlight       = { enable = true },
+     indent          = { enable = true },
+     fold            = { enable = true },
+     textobjects     = { select = { enable = true, lookahead = true } },
+   })
+   ```
+
+3. Build the parser:
+
+   ```vim
+   :TSInstall sisu
+   ```
+
+That is it. Open a `.sst` file - highlighting, folding, and textobject
+selection should all work.
+
+## Install (lazy.nvim)
+
+```lua
+{
+  dir = "/path/to/sisudoc-spine/sundry/editor-syntax-etc/nvim",
+  name = "sisu-spine",
+  ft = { "sisu" },
+  dependencies = { "nvim-treesitter/nvim-treesitter" },
+  config = function()
+    require("sisu-spine").setup()
+  end,
+}
+```
+
+## Sync queries from upstream
+
+The query files are duplicated from `tree-sitter-sisu/queries/` so that
+this Neovim drop-in works without depending on the parser repo's
+checkout layout. To refresh them after grammar changes:
+
+```sh
+cp ../../../sisudoc-spine-tools/tree-sitter-sisu/queries/*.scm \
+   queries/sisu/
+```
+
+(Path is relative to this README.)
+
+## Upstreaming the parser
+
+When the parser is publicly hosted under a stable URL it is worth
+submitting a config to `nvim-treesitter` so users can run `:TSInstall
+sisu` without the local `setup()` call. The required fields are in
+`lua/sisu-spine/init.lua` (`install_info` table); send a PR to
+<https://github.com/nvim-treesitter/nvim-treesitter> patching
+`lua/nvim-treesitter/parsers.lua`.
diff --git a/sundry/editor-syntax-etc/nvim/ftdetect/sisu.lua b/sundry/editor-syntax-etc/nvim/ftdetect/sisu.lua
new file mode 100644
index 0000000..51b4f2f
--- /dev/null
+++ b/sundry/editor-syntax-etc/nvim/ftdetect/sisu.lua
@@ -0,0 +1,7 @@
+vim.filetype.add({
+  extension = {
+    sst = "sisu",
+    ssm = "sisu",
+    ssi = "sisu",
+  },
+})
diff --git a/sundry/editor-syntax-etc/nvim/ftplugin/sisu.lua b/sundry/editor-syntax-etc/nvim/ftplugin/sisu.lua
new file mode 100644
index 0000000..a531238
--- /dev/null
+++ b/sundry/editor-syntax-etc/nvim/ftplugin/sisu.lua
@@ -0,0 +1,13 @@
+-- Buffer-local settings for SiSU spine markup.
+
+vim.bo.commentstring = "%% %s"
+vim.bo.comments = ":%"
+
+-- Soft wrap suits prose.
+vim.wo.wrap = true
+vim.wo.linebreak = true
+
+-- Conceal inline-formatting delimiters when the user opts in
+-- (`:set conceallevel=2`).  See queries/sisu/highlights.scm for
+-- @conceal captures.
+vim.wo.conceallevel = vim.wo.conceallevel
diff --git a/sundry/editor-syntax-etc/nvim/lua/sisu-spine/init.lua b/sundry/editor-syntax-etc/nvim/lua/sisu-spine/init.lua
new file mode 100644
index 0000000..d1ae3df
--- /dev/null
+++ b/sundry/editor-syntax-etc/nvim/lua/sisu-spine/init.lua
@@ -0,0 +1,43 @@
+-- Entry point for the SiSU spine markup Neovim integration.
+--
+-- Registers a tree-sitter parser config so users can run
+--   :TSInstall sisu
+-- to fetch and build the parser via nvim-treesitter.
+--
+-- The parser source lives can be found under the
+-- `projects/` namespace on git.sisudoc.org.
+
+local M = {}
+
+--- Register the `sisu` parser with nvim-treesitter and ensure that
+--- `.sst` / `.ssm` / `.ssi` are detected as filetype "sisu".
+---
+--- Call once from your init.lua before invoking `:TSInstall sisu`.
+function M.setup()
+  local ok, parsers = pcall(require, "nvim-treesitter.parsers")
+  if not ok then
+    vim.notify(
+      "sisu-spine: nvim-treesitter is not installed; "
+        .. "syntax highlighting will not be available.",
+      vim.log.levels.WARN
+    )
+    return
+  end
+
+  local parser_config = parsers.get_parser_configs()
+  parser_config.sisu = {
+    install_info = {
+      url = "https://git.sisudoc.org/projects/tree-sitter-sisu",
+      files = {
+        "src/parser.c",
+        "src/scanner.c",
+      },
+      branch = "main",
+      generate_requires_npm = false,
+      requires_generate_from_grammar = false,
+    },
+    filetype = "sisu",
+  }
+end
+
+return M
diff --git a/sundry/editor-syntax-etc/nvim/queries/sisu/folds.scm b/sundry/editor-syntax-etc/nvim/queries/sisu/folds.scm
new file mode 100644
index 0000000..69c44d2
--- /dev/null
+++ b/sundry/editor-syntax-etc/nvim/queries/sisu/folds.scm
@@ -0,0 +1,23 @@
+; Code folding queries for SiSU Spine markup
+
+; Block elements are foldable
+(code_block_curly) @fold
+(code_block_tic) @fold
+(poem_block_curly) @fold
+(poem_block_tic) @fold
+(block_block_curly) @fold
+(block_block_tic) @fold
+(group_block_curly) @fold
+(group_block_tic) @fold
+(table_block_curly) @fold
+(table_block_tic) @fold
+(quote_block_tic) @fold
+
+; Multi-line book index entries are foldable
+(book_index) @fold
+
+; Pipe tables are foldable
+(pipe_table) @fold
+
+; Header fields with continuations are foldable
+(header_field) @fold
diff --git a/sundry/editor-syntax-etc/nvim/queries/sisu/highlights.scm b/sundry/editor-syntax-etc/nvim/queries/sisu/highlights.scm
new file mode 100644
index 0000000..3454bd4
--- /dev/null
+++ b/sundry/editor-syntax-etc/nvim/queries/sisu/highlights.scm
@@ -0,0 +1,189 @@
+; Syntax highlighting queries for SiSU Spine markup
+; Compatible with tree-sitter highlight capture names from
+; https://tree-sitter.github.io/tree-sitter/syntax-highlighting
+
+; =================================================================
+; Comments
+; =================================================================
+(version_comment) @comment.documentation
+(header_comment) @comment
+(body_comment) @comment
+
+; =================================================================
+; Header (document metadata)
+; =================================================================
+(header_field
+  key: (header_key) @keyword)
+
+(header_field
+  value: (header_value) @string)
+
+(header_continuation) @string
+
+; =================================================================
+; Headings
+; =================================================================
+(part_marker) @keyword.directive
+(segment_marker) @keyword.directive
+
+(heading_part
+  content: (heading_content) @markup.heading)
+
+(heading_segment
+  content: (heading_content) @markup.heading)
+
+(segment_name) @label
+(suppress_marker) @punctuation.special
+
+; Heading levels for more specific styling
+(heading_part
+  marker: (part_marker) @markup.heading.1
+  (#match? @markup.heading.1 "^:A~$"))
+
+(heading_part
+  marker: (part_marker) @markup.heading.2
+  (#match? @markup.heading.2 "^:B~$"))
+
+(heading_part
+  marker: (part_marker) @markup.heading.3
+  (#match? @markup.heading.3 "^:C~$"))
+
+(heading_part
+  marker: (part_marker) @markup.heading.4
+  (#match? @markup.heading.4 "^:D~$"))
+
+(heading_segment
+  marker: (segment_marker) @markup.heading.5
+  (#match? @markup.heading.5 "^1~$"))
+
+(heading_segment
+  marker: (segment_marker) @markup.heading.6
+  (#match? @markup.heading.6 "^2~$"))
+
+; =================================================================
+; Inline formatting
+; =================================================================
+(emphasis) @markup.italic
+(bold) @markup.bold
+(italic) @markup.italic
+(underline) @markup.underline
+(citation_mark) @markup.quote
+(superscript) @markup.superscript
+(subscript) @markup.subscript
+(inserted) @markup.underline
+(strikethrough) @markup.strikethrough
+(monospace_inline) @markup.raw
+
+; Formatting delimiters
+["*{" "}*"] @punctuation.special
+["!{" "}!"] @punctuation.special
+["/{" "}/"] @punctuation.special
+["_{" "}_"] @punctuation.special
+["\"{" "}\""] @punctuation.special
+["^{" "}^"] @punctuation.special
+[",{" "},"] @punctuation.special
+["+{" "}+"] @punctuation.special
+["-{" "}-"] @punctuation.special
+["#{" "}#"] @punctuation.special
+
+; =================================================================
+; Footnotes and editor notes
+; =================================================================
+(footnote) @markup.link
+(footnote_marker) @punctuation.special
+(editor_note) @markup.link
+
+["~{" "}~"] @punctuation.special
+; Editor-note channel selector: ~[* (asterisk set) or ~[+ (plus set).
+; A distinct capture lets themes colour the two channels separately
+; from the generic footnote delimiters above.
+(editor_note_marker) @attribute
+["]~"] @punctuation.special
+
+; =================================================================
+; Links and images
+; =================================================================
+(link
+  text: (link_text) @markup.link.label)
+
+(link
+  target: (url) @markup.link.url)
+
+(link
+  target: (anchor_ref) @markup.link.url)
+
+(link
+  target: (collection_path) @markup.link.url)
+
+(auto_footnote_marker) @punctuation.special
+
+(image
+  spec: (image_spec) @markup.link.label)
+
+(url) @markup.link.url
+
+(inline_anchor) @label
+(anchor_name) @label
+
+; =================================================================
+; Block elements
+; =================================================================
+(block_open) @keyword.directive
+(block_close) @keyword.directive
+(raw_content) @markup.raw
+
+; Code blocks get more specific highlighting
+(code_block_curly
+  open: (block_open) @keyword.directive)
+(code_block_curly
+  content: (raw_content) @markup.raw.block)
+(code_block_curly
+  close: (block_close) @keyword.directive)
+
+(code_block_tic
+  open: (block_open) @keyword.directive)
+(code_block_tic
+  content: (raw_content) @markup.raw.block)
+(code_block_tic
+  close: (block_close) @keyword.directive)
+
+; =================================================================
+; Book index
+; =================================================================
+(book_index) @markup.list
+(index_content) @string
+
+; =================================================================
+; Paragraph prefixes
+; =================================================================
+(paragraph_prefix) @punctuation.special
+
+; =================================================================
+; Special markers
+; =================================================================
+(ocn_suppress) @comment
+(ocn_suppress_open) @comment
+(ocn_suppress_close) @comment
+
+(page_break) @punctuation.special
+(horizontal_rule) @punctuation.special
+
+; =================================================================
+; Composite includes
+; =================================================================
+(composite_include) @keyword.import
+(include_path) @string.special.path
+
+; =================================================================
+; Pipe table
+; =================================================================
+(table_spec) @keyword.directive
+(table_row) @markup.raw
+
+; =================================================================
+; Text
+; =================================================================
+(text) @spell
+
+; Line break
+(line_break) @punctuation.special
diff --git a/sundry/editor-syntax-etc/nvim/queries/sisu/indents.scm b/sundry/editor-syntax-etc/nvim/queries/sisu/indents.scm
new file mode 100644
index 0000000..aa73af8
--- /dev/null
+++ b/sundry/editor-syntax-etc/nvim/queries/sisu/indents.scm
@@ -0,0 +1,48 @@
+; Indentation queries for SiSU Spine markup.
+;
+; SiSU markup is largely flat: paragraphs and headings live at column 0,
+; block bodies preserve their author-supplied indentation verbatim, and
+; nesting is by markers rather than by indent. So indents.scm is mostly a
+; no-op - the goal is to ensure that auto-indent on <CR> stays at column 0
+; for normal lines and respects existing indentation inside header
+; continuations and blocks.
+
+; Tree-sitter indent semantics (per nvim-treesitter and treesit):
+;   @indent.begin - increases indent for the following line
+;   @indent.end   - matches the @indent.begin and decreases indent
+;   @indent.zero  - resets indent to column 0
+;   @indent.align - aligns following lines with this node
+;   @indent.branch - same level as the parent (for else/elif-style joins)
+
+; Top-level structures live at column 0 - reset to zero on the next line.
+(heading_part)         @indent.zero
+(heading_segment)      @indent.zero
+(paragraph)            @indent.zero
+(book_index)           @indent.zero
+(composite_include)    @indent.zero
+(page_break)           @indent.zero
+(horizontal_rule)      @indent.zero
+(ocn_suppress_open)    @indent.zero
+(ocn_suppress_close)   @indent.zero
+(body_comment)         @indent.zero
+
+; Block elements: opening line increases indent for the body, closing
+; line returns to zero. Editors that respect this will visually indent
+; raw content one step from the delimiter line, which is conventional.
+(code_block_curly)  @indent.align
+(code_block_tic)    @indent.align
+(poem_block_curly)  @indent.align
+(poem_block_tic)    @indent.align
+(block_block_curly) @indent.align
+(block_block_tic)   @indent.align
+(group_block_curly) @indent.align
+(group_block_tic)   @indent.align
+(table_block_curly) @indent.align
+(table_block_tic)   @indent.align
+(quote_block_tic)   @indent.align
+
+; Header continuation lines are indented by two spaces from column 0;
+; mark continuations as align so a host that chooses to auto-indent the
+; next continuation line matches the previous one.
+(header_field)         @indent.align
+(header_continuation)  @indent.align
diff --git a/sundry/editor-syntax-etc/nvim/queries/sisu/injections.scm b/sundry/editor-syntax-etc/nvim/queries/sisu/injections.scm
new file mode 100644
index 0000000..27f622b
--- /dev/null
+++ b/sundry/editor-syntax-etc/nvim/queries/sisu/injections.scm
@@ -0,0 +1,16 @@
+; Language injection queries for SiSU Spine markup
+;
+; Code blocks could potentially inject language-specific highlighting,
+; but SiSU code blocks don't specify language. These queries are
+; provided as a starting point for future extension.
+
+; Code block content could be injected with a specific language
+; if the block type or context provides a hint.
+; For now, raw content in code blocks is left unhighlighted.
+
+; Example: if code blocks specified a language, e.g. code(d){
+; ((code_block_curly
+;   open: (block_open) @_open
+;   content: (raw_content) @injection.content)
+;  (#match? @_open "code\\(d\\)")
+;  (#set! injection.language "d"))
diff --git a/sundry/editor-syntax-etc/nvim/queries/sisu/textobjects.scm b/sundry/editor-syntax-etc/nvim/queries/sisu/textobjects.scm
new file mode 100644
index 0000000..0a82481
--- /dev/null
+++ b/sundry/editor-syntax-etc/nvim/queries/sisu/textobjects.scm
@@ -0,0 +1,140 @@
+; Text-object queries for SiSU Spine markup.
+;
+; Capture conventions follow nvim-treesitter/textobjects:
+;   @<thing>.outer  -> select including delimiters / surrounding whitespace
+;   @<thing>.inner  -> select content only
+;
+; Hosts that consume these (Neovim's nvim-treesitter-textobjects, Helix,
+; Emacs treesit) bind keys such as `af` / `if` to .outer / .inner.
+
+; =================================================================
+; Headings (sectioning units)
+; =================================================================
+; A whole heading line is a "section header" object. Heading sections
+; (the heading plus its body content up to the next heading of equal or
+; higher level) are not directly expressible in tree-sitter without
+; additional grammar work; hosts can synthesise that from these captures.
+
+(heading_part) @class.outer
+(heading_part
+  content: (heading_content) @class.inner)
+
+(heading_segment) @class.outer
+(heading_segment
+  content: (heading_content) @class.inner)
+
+; =================================================================
+; Block elements (code / poem / block / group / table / quote)
+; =================================================================
+; Whole block including delimiters; raw_content is the inner.
+
+(code_block_curly) @function.outer
+(code_block_curly
+  content: (raw_content) @function.inner)
+
+(code_block_tic) @function.outer
+(code_block_tic
+  content: (raw_content) @function.inner)
+
+(poem_block_curly) @function.outer
+(poem_block_curly
+  content: (raw_content) @function.inner)
+
+(poem_block_tic) @function.outer
+(poem_block_tic
+  content: (raw_content) @function.inner)
+
+(block_block_curly) @function.outer
+(block_block_curly
+  content: (raw_content) @function.inner)
+
+(block_block_tic) @function.outer
+(block_block_tic
+  content: (raw_content) @function.inner)
+
+(group_block_curly) @function.outer
+(group_block_curly
+  content: (raw_content) @function.inner)
+
+(group_block_tic) @function.outer
+(group_block_tic
+  content: (raw_content) @function.inner)
+
+(table_block_curly) @function.outer
+(table_block_curly
+  content: (raw_content) @function.inner)
+
+(table_block_tic) @function.outer
+(table_block_tic
+  content: (raw_content) @function.inner)
+
+(quote_block_tic) @function.outer
+(quote_block_tic
+  content: (raw_content) @function.inner)
+
+(pipe_table) @function.outer
+
+; =================================================================
+; Footnotes and editor notes
+; =================================================================
+; Both share the same outer/inner shape; the inner skips the markers and
+; closing delimiters.
+
+(footnote) @comment.outer
+(footnote
+  (_)+ @comment.inner)
+
+(editor_note) @comment.outer
+(editor_note
+  (_)+ @comment.inner)
+
+; =================================================================
+; Links and images
+; =================================================================
+
+(link) @parameter.outer
+(link
+  text: (link_text) @parameter.inner)
+
+(image) @parameter.outer
+(image
+  spec: (image_spec) @parameter.inner)
+
+; =================================================================
+; Paragraph / inline-formatting runs
+; =================================================================
+
+(paragraph) @block.outer
+(paragraph
+  (_)+ @block.inner)
+
+; Inline formatting pairs - useful as fine-grained text objects.
+; The same delimiter character pattern (e.g. `*{` / `}*`) opens and
+; closes each, so .inner is everything between them.
+
+(emphasis)         @assignment.outer
+(bold)             @assignment.outer
+(italic)           @assignment.outer
+(underline)        @assignment.outer
+(citation_mark)    @assignment.outer
+(superscript)      @assignment.outer
+(subscript)        @assignment.outer
+(inserted)         @assignment.outer
+(strikethrough)    @assignment.outer
+(monospace_inline) @assignment.outer
+
+; =================================================================
+; Book index entries
+; =================================================================
+
+(book_index) @attribute.outer
+(book_index
+  (index_content) @attribute.inner)
+
+; =================================================================
+; Header fields
+; =================================================================
+
+(header_field) @assignment.outer
+(header_field
+  value: (header_value) @assignment.inner)