3 ms·

How does an editor handle loading from disk and updating when someones inserts to the head of a file? Everything needs to be shifted.

• ars 8y ago
  You use a https://en.wikipedia.org/wiki/Rope_(data_structure) https://en.wikipedia.org/wiki/Rope_(data_structure) and not a flat string. You only flatten the string when it's time to write to disk. For autosave files make sure to store the changes to the rope, not the full text.
  • lighttower 8y ago
    There is a comment somewhere on HN from the guy that wrote the mapping trick that Word (or WordPerfect) invented way back. They were saving changes to the file rather than flattening. I wish I could find it now.
    • ygra 8y ago
      The data structure is called a piece table, if that ids your search.
      • pkaye 8y ago
        According to Wikipedia, it looks like Visual Studio Code is using this data structure.