[pdftex] Caching intermediate compilation results for near-real-time PDF re-renders during editing

[Doug McKenna]

For documents with tables of contents, extending a section or chapter title by one word (or even letter) on page N could conceivably increase the earlier Table of Contents by one line, which could conceivably cause the table of contents to require one more page, which then could change the page numbering of every page following in the rest of the document.

This is one reason why Knuth chose fixed-point arithmetic, and TeX's own implementation of fixed-point math, to avoid the butterfly/avalanche effect of even a single low-order bit difference in typesetting measurements.

Doug McKenna