Why ranges, not spans

IDML models styled text as nested ranges, not inline spans, because formatting in a paged layout follows paragraph and run boundaries.

In short: HTML models styled text as inline spans wrapping characters, free to start and end anywhere. IDML instead nests ranges: a ParagraphStyleRange containing CharacterStyleRange blocks containing Content. Because each paragraph owns one paragraph style and each run owns one set of character formatting, the range shape encodes those boundaries directly, which fits a paginated, style-driven layout better than overlapping spans. This page explains why and what it implies for anyone walking the tree.

HTML models styled text as inline spans wrapping characters. IDML instead models it as nested ranges — a paragraph-style range containing character-style ranges containing content. This page explains why that shape fits a paginated, style-driven layout model better, and what it implies for anyone walking the tree.

🚧 Being written.

Frequently asked questions

What is the difference between a range and a span? A span (as in HTML) wraps an arbitrary stretch of characters and can start or end anywhere. A range in IDML is tied to a structural boundary: a ParagraphStyleRange is exactly one paragraph and a CharacterStyleRange is exactly one run of uniform character formatting.

Why does IDML nest ranges instead of wrapping spans? Because formatting in a page layout follows paragraph and run boundaries: each paragraph has one paragraph style and each run has one set of character formatting. Nesting CharacterStyleRange blocks inside a ParagraphStyleRange encodes those boundaries directly, with no overlapping or ambiguous nesting to resolve.

What does the range model mean for walking the tree? Each level maps cleanly to a unit you iterate over: paragraphs are ParagraphStyleRange blocks, runs are CharacterStyleRange blocks, and text is in Content. Counting paragraphs or runs is just counting those blocks — see story structure.