David Kastrup wrote:
I think that 0.25.x might have the big bad hyphenation bug.
It had several of those, in fact.
However, I suppose even when using a version where this has been sorted out, TeX's behavior for things like shelf{}ful will not be imitated (in this case, TeX separates the ligature unless it does a hyphenation pass on the paragraph (can be forced with \pretolerance=-10000) in which case the ligature will get recombined. That's not something worth imitating.
Last time we checked the typeset output (two weeks ago), there were some dozens of differences between pdftex and luatex when compiling the texbook, and these differences were all in one of three categories: * Missed hyphenations. This is a known bug caused by nested discretionaries that will be solved eventually (#9 in the tracker) * Additional hyphenations (in typewriter text). These were added because luatex is willing to hyphenate words that start with a non-letter: luatex just starts the word at the first thing that is a letter. An argument can be made for maintaining compatibility, but currenty we do not intent to make that change as the new behaviour is desired much more often. (the same can be said for hyphenating the first word in a paragraph, but that case never arises in the texbook) * Extra or slightly different ligatures. These are caused by stuff like the self{}ful example above, and this incompatibity will definately remain. TeX's exact behaviour was an implementation artifact that is pretty hard to mimic, and any attempt to do so would lead to extremely ugly code. Best wishes, Taco