On 23-12-2009 18:29, Paweł Jackowski wrote:
Taco Hoekwater wrote:
Paweł Jackowski wrote:
someglyph.next = someother discretionary.pre = someglyph
is not the same. Why?
Hans:
indeed strange ... a quick hack is to use node.copy on b
Copying the node works in that case, thanks.
Taco:
Because a discretionary's pre, post, and replace lists are a bit special: internally the discretionary does not just have a next and a prev link for each of the head nodes, but also a 'tail' link. That last one points to the last node in the list for each of the three fields. That extra link is used during hyphenation and at end-of-line situations (those parts of the code would be much more complex == slower without it).
Agh, having the disc.tail link(s) at lua level would simplify processing discretionaries a lot! Why you decided not to interface tails?
we had node.slide (for making two way linked node lists) and now also have node.tail so you can find the tail if needed tail = node.tail(n.pre)
I also noticed that assigning disc sublists introduces nested_list nodes:
someglyph.prev = nil disc.pre = someglyph assert(someglyph.prev.id==node.id"nested_list")
Is this related here? Is the user supposed to take care about nested_list nodes (to create them, to destroy them)?
normally not ; similar effects can occur when messing around with boxes (.list) ... it is often best to work with a copy and assign the result of messing with the copy ... the speed penalty is neglectable Hans ----------------------------------------------------------------- Hans Hagen | PRAGMA ADE Ridderstraat 27 | 8061 GH Hasselt | The Netherlands tel: 038 477 53 69 | fax: 038 477 53 74 | www.pragma-ade.com | www.pragma-pod.nl -----------------------------------------------------------------