2014-05-21 18:17 GMT+03:00 Eli Zaretskii : > > Date: Wed, 21 May 2014 11:34:10 +0300 > > From: Alin Soare > > Cc: Stefan Monnier , emacs-devel@gnu.org > > > > Ideally, at each node all the text should have the same properties > (marks, > > fonts, etc), and chaging 1 such property can be implemented by splitting > > the node or removing a few nodes, and their text be preserved in 1 node > > (only the field owner must be changed when a few nodes are joined in only > > 1). > > That would mean we will need to rearrange the tree each time text > properties or overlays change, something we avoid today. > Yes, each time ! But however, a simple mental computation is still much faster than now, because the computation is made only 1 for each change, and there will be lots of simple pre-computations that never repeat. Not all the attributes will be pre-computed at the creation of the node. Some attributes, like # of newlines on the text at the left of the node and on the self will be precomputed at the creation. The Node->marks will be perhaps precomputed when some mark is added in the text within the node. Display props are pre-computed when the redisplay-internal requires it, so kind of lazy. > Also please note that 'display' properties can specify that Emacs > displays something entirely different from buffer text, so the display > engine will still need to consult Lisp strings, in addition to the > text. (Yes, it's lots of fun.) > What is displayed will be all the time pre-computed for each node, and this will never be re-computed for that node before modifications. The attribute NODE->what-to-display-data perhaps will be evaluated at the 1st display, not at the node creation. Note also that I will do such that each node keeps not a block of text, but a linked list of blocks of text, such that to be fast to manipulate operations like join and split. Apart from search in buffer and reading the text at a given offset(point), that will be a little slower because the problem of page cache, all the other functions will be faster (at a first sight). We will see. When i start working, I will send you private message to ask you to read what I did. Try since October on to do it.