View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0000372 | luatex | luatex bug | public | 2010-04-06 12:52 | 2015-10-25 10:41 |
| Reporter | Taco | Assigned To | Taco | ||
| Priority | normal | Severity | minor | Reproducibility | have not tried |
| Status | closed | Resolution | fixed | ||
| Target Version | 0.80.0 | ||||
| Summary | 0000372: Fix \predisplaydirection | ||||
| Description | The relevant bit of code has been lost in the merge of Aleph. | ||||
| Additional Information | From Vafa: It is an internal read/write integer, initialised by e-TeX to indicate the direction of the last partial paragraph before a display; it is used to control the placement of elements such as equation numbers, and can be explictly set to affect this placement. If you give value, say, 0 or a positive value, say 1, there is no difference (i.e. \eqno apears on RHS, and \leqno apears on LHS) but if you give a negative value, say -1, then \eqno will appear on LHS and \leqno will appear on RHS. | ||||
| Tags | math | ||||
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commit 3600 is an attempt at fixing this. luatex now initializes \predisplaydirection to -1 in \mathdir and \pardir are opposite, or to 0 in other cases. The post-display code tests for \predisplaydirection<0. If so, it will swap the location of the equation number. I hope this was the intended use. |
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3600 introduced or highlighted other bugs, so I have taken a step back: Let's forget about the ability to set \predisplaydirection manually for a moment, and focus on the core functionality first. The big question is this: should \eqno and \leqno adhere to \pardir, to \mathdir, or simply be physical right and left without regard to direction specifiers at all? I don't know the answer to that, so somebody has to enlighten me. |
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May preference is to treat left and right as "start of the line" and "end of the line", so that existing macro code will give the logically expected result when one switches direction (one setting equation number to the right is actually expecting it at the start of the line). If one wants right and left to be always physical right and left, then this has to be done at macro not at engine level. In an ideal world, we would use a start/end nomenclature (lets not forget about vertical typesetting, even if it isn't working properly right now), but I'm not going to demand this. |
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2010-04-06 12:52 | Taco | New Issue | |
| 2010-04-06 12:52 | Taco | Status | new => assigned |
| 2010-04-06 12:52 | Taco | Assigned To | => Taco |
| 2010-04-07 14:30 | Taco | Note Added: 0000526 | |
| 2010-04-07 14:30 | Taco | Status | assigned => feedback |
| 2010-04-08 09:09 | Taco | Note Added: 0000527 | |
| 2010-04-08 09:09 | Taco | Status | feedback => assigned |
| 2010-04-08 09:09 | Taco | Status | assigned => feedback |
| 2010-04-08 11:56 | Khaled Hosny | Note Added: 0000528 | |
| 2010-04-18 06:32 | Taco | Target Version | 0.60.1 => 0.70.0 |
| 2010-04-18 06:32 | Taco | Additional Information Updated | |
| 2010-04-18 06:32 | Taco | Status | feedback => assigned |
| 2011-04-12 09:09 | Taco | Target Version | 0.70.0 => 0.80.0 |
| 2012-04-09 02:56 | Khaled Hosny | Tag Attached: math | |
| 2015-10-25 10:41 | Hans Hagen | Status | assigned => closed |
| 2015-10-25 10:41 | Hans Hagen | Resolution | open => fixed |
