Module source_line_anchors 

Source-line anchor injection for the HTML renderer.

When Options::source_line_anchors is true, top-level block elements in the rendered HTML get a data-afm-source-line="N" attribute (1-based) pointing back at the source line where the block began. The afm-obsidian document-mode adapter (Pillar 6) relies on this to map Obsidian’s per-block post-processor calls back to slices of the full rendered fragment.

Algorithm:

1. Walk comrak’s top-level AST children (root.children()) and collect each child’s source position from node.data.borrow().sourcepos.start.line.
2. After comrak emits the HTML string, scan it once and inject data-afm-source-line="N" into the first opening tag at each top-level block boundary. Top-level blocks are identified positionally — the Nth top-level element in the HTML corresponds to the Nth child of the comrak root.

Why string-level injection rather than custom rendering: comrak’s format_html doesn’t expose a per-node attribute hook on every block kind we care about. A scan-and-inject pass is O(html) and deterministic; the per-element overhead is dwarfed by the comrak formatter’s own cost.

Functions

collect_top_level_lines 🔒

1-based source line for each top-level child, in document order.

find_tag_end 🔒

inject_anchors 🔒

Insert data-afm-source-line="N" into the first opening tag at each top-level block boundary. Tags considered top-level are <p>, <h1..h6>, <ul>, <ol>, <blockquote>, <pre>, <table>, <hr>, <div> (containers).

inject_attribute 🔒

is_top_level_tag 🔒

is_void_tag 🔒

tag_name 🔒