ocda: warn if heading claims reserved segment name

spine automatically builds some segments, including: (toc, endnotes,
glossary, bibliography, bookindex, blurb, _the_title) these are now
identified as reserved names and a user is now warned if any of these
names have been manually assigned to a heading by markup. A document
still builds but to disambiguate the ocn of the heading is attached to
the markup (reserved) name and this is seeded before a document not
after. It is read off the finished abstraction rather than reported by
the parser, and beside the ocn alignment check for the same reason: it
is a statement about a document rather than a step in building one.

  WARNING reserved segment name: the_autonomous_contract... [en]
    heading 1 at ocn 135 asks for "endnotes", which spine gives its
    own generated section
      it is named "endnotes-135" instead; ...

A warning: the document is correct and complete and the name it ends
up with works.

--strict makes it a failure for the run, as it does for ocn alignment,
and by the same reasoning: the outputs are written and can be looked at,
and the exit status is taken at the end.

Two of the thirty-six sample documents have reserved segment names,
"1~endnotes" heading. Output is unchanged: nothing here touches the
abstraction.

(assisted by Claude-Code)

3 files changed, 225 insertions, 8 deletions

diff --git a/src/sisudoc/ocda/meta/metadoc_from_src.d b/src/sisudoc/ocda/meta/metadoc_from_src.d
index 2731573..3670a39 100644
--- a/src/sisudoc/ocda/meta/metadoc_from_src.d
+++ b/src/sisudoc/ocda/meta/metadoc_from_src.d
@@ -97,6 +97,18 @@ template docAbstraction() {
       anchor_tag = "";
       _heading_anchor_tags_seen = _reserved_heading_anchor_tags();
     }
+    /+ ↓ seeded here, on the way in, which is the seeding that matters.
+         .
+         The two assignments in scope(exit) and at the tail of this function run
+         after a document has been abstracted, so they seed the *next* one. The
+         first document of a run had nothing before it and began with the set as
+         declared, empty: it alone was not held to the reserved names, and a heading
+         of its own claiming "endnotes" kept the name of the generated section.
+         Which document that was depended on what else was in the run, so a
+         document's abstraction depended on its company, and a single document
+         re-parsed to check an artefact made in a collection run disagreed with it.
+    +/
+    _heading_anchor_tags_seen = _reserved_heading_anchor_tags();
     mixin spineNode;
     int[string] node_para_int_     = node_metadata_para_int;
     string[string] node_para_str_  = node_metadata_para_str;
diff --git a/src/sisudoc/ocda/meta/metadoc_from_src_functions.d b/src/sisudoc/ocda/meta/metadoc_from_src_functions.d
index 0deeb72..c5a63cd 100644
--- a/src/sisudoc/ocda/meta/metadoc_from_src_functions.d
+++ b/src/sisudoc/ocda/meta/metadoc_from_src_functions.d
@@ -77,16 +77,15 @@ template docAbstractionFunctions() {
        these names means the document's heading is disambiguated the same
        way a repeated anchor tag is, and the generated section keeps the
        name that the table of contents links to.
+       .
+       The list itself is in sisudoc.ocda.meta.reserved_names, with the
+       check that reports such a heading to its author. Two lists would be
+       two answers to what spine has taken.
   +/
   bool[string] _reserved_heading_anchor_tags() {
-    bool[string] _reserved;
-    foreach (_name; [
-      "toc", "endnotes", "glossary", "bibliography", "bookindex", "blurb",
-      "_the_title",
-    ]) {
-      _reserved[_name] = true;
-    }
-    return _reserved;
+    import sisudoc.ocda.meta.reserved_names;
+    mixin spineReservedNames _rn;
+    return _rn.reservedHeadingAnchorTags();
   }
   string lev_anchor_tag;
   string[string][string] tag_assoc;
diff --git a/src/sisudoc/ocda/meta/reserved_names.d b/src/sisudoc/ocda/meta/reserved_names.d
new file mode 100644
index 0000000..8e49ae5
--- /dev/null
+++ b/src/sisudoc/ocda/meta/reserved_names.d
@@ -0,0 +1,206 @@
+/+
+- Name: SisuDoc Spine, Doc Reform [a part of]
+  - Description: documents, structuring, processing, publishing, search
+    - static content generator
+
+  - Author: Ralph Amissah
+    [ralph.amissah@gmail.com]
+
+  - Copyright: (C) 2015 (continuously updated, current 2026) Ralph Amissah, All Rights Reserved.
+
+  - License: AGPL 3 or later:
+
+    Spine (SiSU), a framework for document structuring, publishing and
+    search
+
+    Copyright (C) Ralph Amissah
+
+    This program is free software: you can redistribute it and/or modify it
+    under the terms of the GNU AFERO General Public License as published by the
+    Free Software Foundation, either version 3 of the License, or (at your
+    option) any later version.
+
+    This program is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+    more details.
+
+    You should have received a copy of the GNU General Public License along with
+    this program. If not, see [https://www.gnu.org/licenses/].
+
+    If you have Internet connection, the latest version of the AGPL should be
+    available at these locations:
+    [https://www.fsf.org/licensing/licenses/agpl.html]
+    [https://www.gnu.org/licenses/agpl.html]
+
+  - Spine (by Doc Reform, related to SiSU) uses standard:
+    - docReform markup syntax
+      - standard SiSU markup syntax with modified headers and minor modifications
+    - docReform object numbering
+      - standard SiSU object citation numbering & system
+
+  - Homepages:
+    [https://www.sisudoc.org]
+    [https://www.doc-reform.org]
+
+  - Git
+    [https://git.sisudoc.org/]
+
++/
+/++
+  the segment names spine keeps for itself<br><br>
+
+  the one list of them, and the check that says when a document's own
+  heading has claimed one<br><br>
+
+  [sisudoc.ocda.meta.reserved_names]
++/
+module sisudoc.ocda.meta.reserved_names;
+@safe:
+/+ ↓ spine names the sections it generates, these names are reserved.
+     .
+     The table of contents, the gathered endnotes, the glossary, the
+     bibliography, the book index and the blurb are not in the markup: spine
+     makes them, and gives each a segment name of its own. A document whose
+     own heading asks for one of those names ("1~endnotes Endnote") is asking
+     for a name that is already taken, and before this was noticed both wrote
+     into the same file: the generated section and the author's heading, with
+     the navigation listing that file twice, the second time behind its own
+     earlier entry in reading order.
+     .
+     The parser therefore seeds the set of heading anchor names it has seen
+     with these before it reads a document, so that a heading claiming one is
+     disambiguated by ocn suffix the same way a repeated anchor tag is, and
+     the generated section keeps the name the table of contents links to.
+     .
+     Two things live here rather than in the parser:
+     .
+       the list      so that the parser's seeding and the check below cannot
+                     come to hold different ideas of what is reserved;
+                     .
+       the check     which runs over a finished abstraction, names the
+                     headings that were renamed, and is what tells an author
+                     that a heading of theirs is not called what they wrote.
+                     A warning: the document is correct and complete, and the
+                     name it ends up with works. --strict makes it a failure,
+                     for the run that is meant to be publishable.
+     .
+     The renaming is not something the author has to accept. A heading given
+     any other anchor name ("1~my-notes Endnote") keeps it, and the warning
+     goes away.
++/
+/+ ↓ mixed in as a named mixin (mixin spineReservedNames _name;) and its
+     imports are inside its functions rather than at template scope: what a
+     mixin template declares at its own scope is visible in the scope it is
+     mixed into, and an import there can hijack a name the host was already
+     resolving by UFCS.
++/
+template spineReservedNames() {
+  /+ ↓ the names spine makes for itself, in one place.
+       _the_title is the head section's own; the rest are the generated
+       sections, and are the section keys of the abstraction.
+  +/
+  string[] reservedHeadingAnchorNames() {
+    return [
+      "toc", "endnotes", "glossary", "bibliography", "bookindex", "blurb",
+      "_the_title",
+    ];
+  }
+  /+ ↓ the same, as the set the parser seeds itself with +/
+  bool[string] reservedHeadingAnchorTags() {
+    bool[string] _reserved;
+    foreach (_name; reservedHeadingAnchorNames()) { _reserved[_name] = true; }
+    return _reserved;
+  }
+  /+ ↓ one heading that asked for a name spine had already taken +/
+  struct ST_ReservedNameUse {
+    string section;    // where in the abstraction it sits
+    string reserved;   // the name it asked for
+    string anchor;     // the name it was given instead
+    string level;      // as marked up, :A :B 1 2 ...
+    int    ocn;
+  }
+  /+ ↓ was this heading renamed out of the way of a reserved name?
+       .
+       Read off the anchor rather than reported by the parser: the parser
+       renames by appending the object's number, so "endnotes" becomes
+       "endnotes-135" on the object whose ocn is 135, and that pairing is what
+       identifies it. Requiring the number to be the object's own is what keeps
+       a heading an author really did call "endnotes-135" from being reported as
+       something it is not.
+  +/
+  private string _reservedNameClaimedBy(O)(O obj) {
+    import std.conv : to;
+    string _anchor = obj.tags.anchor_tag_html;
+    if (_anchor.length == 0) { return ""; }
+    string _suffix = "-" ~ obj.metainfo.ocn.to!string;
+    if (_anchor.length <= _suffix.length) { return ""; }
+    if (_anchor[($ - _suffix.length) .. $] != _suffix) { return ""; }
+    string _stem = _anchor[0 .. ($ - _suffix.length)];
+    foreach (_name; reservedHeadingAnchorNames()) {
+      if (_stem == _name) { return _name; }
+    }
+    return "";
+  }
+  /+ ↓ every heading of a document that claimed a reserved name.
+       document order, the section order the .ssp is written in, so that two
+       runs over the same document report it the same way round.
+  +/
+  ST_ReservedNameUse[] reservedNameHeadings(D)(D doc) {
+    import std.algorithm : canFind, sort;
+    import std.conv : to;
+    ST_ReservedNameUse[] _out;
+    string[] _sections = ["head", "toc", "body", "endnotes",
+      "glossary", "bibliography", "bookindex", "blurb", "tail"];
+    string[] _extra;
+    foreach (_k; doc.abstraction.byKey) {
+      if (!_sections.canFind(_k)) { _extra ~= _k; }
+    }
+    foreach (_k; _extra.sort) { _sections ~= _k; }
+    foreach (section; _sections) {
+      if (section !in doc.abstraction) { continue; }
+      foreach (obj; doc.abstraction[section]) {
+        if (obj.metainfo.is_a != "heading") { continue; }
+        string _claimed = _reservedNameClaimedBy(obj);
+        if (_claimed.length == 0) { continue; }
+        /+ ↓ the generated sections carry the reserved names themselves and are
+             not what this is about: they are headings spine made, and they keep
+             the plain name. Only an object that was renamed reaches here, and a
+             generated one never is.
+        +/
+        ST_ReservedNameUse _u;
+        _u.section  = section;
+        _u.reserved = _claimed;
+        _u.anchor   = obj.tags.anchor_tag_html;
+        _u.level    = obj.metainfo.marked_up_level;
+        _u.ocn      = obj.metainfo.ocn.to!int;
+        _out ~= _u;
+      }
+    }
+    return _out;
+  }
+  /+ ↓ the report, as the lines to print.
+       the document is named once and its headings indented under it, as the ocn
+       alignment check does, so that a run over a collection reads as a list of
+       documents.
+  +/
+  string[] reservedNameReportLines(
+    string             doc_key,
+    string             lang,
+    ST_ReservedNameUse[] _uses,
+  ) {
+    import std.conv : to;
+    string[] _out;
+    if (_uses.length == 0) { return _out; }
+    _out ~= "WARNING reserved segment name: " ~ doc_key
+      ~ ((lang.length > 0) ? " [" ~ lang ~ "]" : "");
+    foreach (_u; _uses) {
+      _out ~= "  heading " ~ _u.level ~ " at ocn " ~ _u.ocn.to!string
+        ~ " asks for \"" ~ _u.reserved
+        ~ "\", which spine gives its own generated section";
+      _out ~= "    it is named \"" ~ _u.anchor
+        ~ "\" instead; give the heading another name to keep one of your own";
+    }
+    return _out;
+  }
+}