Function declare_node_matches 

pub fn declare_node_matches(
    document: &Document,
    node: &Node,
    pat: &DeclarePattern,
) -> bool

Rust-side filtering for \lxDeclare pattern matching. XPath matches are broad (to avoid nested predicate bugs); this function verifies the matched node’s children match the specific pattern.

Pattern types:

• “subscript”: node is XMApp[@role='POSTSUBSCRIPT'], check base text + optional sub text
• “prime”: node is XMApp[@role='POSTSUPERSCRIPT'], check base text
• “accent”: node is XMApp, check accent name in first child, optional base text
• “simple”: no extra filtering needed (XPath is specific enough)