Module resilient.patches.overhang
Experimental hanging punctuation (overhang) support.
This file is part of re·sil·ient, a set of extensions to SILE.
See LIMITATIONS below.
Knuth said that hanging punctuation is a solved problem... There are (at least) two approaches, for the general case:
One is to cancel the width of the punctuation and to add the overhang width to the next glue. It thus require a lookahead to check that there is a glue after the punctuation, and to modify it.
The other is to insert two kerns after the punctuation (one negative, one positive), and to let the Knuth-Plass line breaker do its job (see TeXbook, app. D "dirty tricks").
This implementation uses the second approach.
Both approaches requires some tweaks at the node breaking (segmenter) level, so this is what we do here, though in a monkey-patch way.
Discretionary nodes neeed another dedicated approach. It's simpler, in a way, because we can just tweak the width of the prebreak content.
Info:
- Copyright: (c) 2025 Omikhkeia / Didier Willis
- License: MIT
Class SILE.nodeMakers.unicode
| unicode.makeOverhang (self, w) | (Hard-patch) Add a makeOverhang() method to the unicode node maker. |
| unicode.handleWordBreak (self, item) | (Hard-patch) Override the handleWordBreak method. |
Class SILE.types.node.discretionary
| discretionary:_init (...) | (Hard-patch) Override the discretionary constructor to adjust the width of the prebreak. |
Class SILE.nodeMakers.unicode
- unicode.makeOverhang (self, w)
-
(Hard-patch) Add a makeOverhang() method to the unicode node maker.
Parameters:
- self Instance pointer
- w number Width of the overhang
- unicode.handleWordBreak (self, item)
-
(Hard-patch) Override the handleWordBreak method.
LIMITATIONS:
This will NOT work for languages that inherit from unicode but override handleWordBreak, such as:
- French (because of the special space rules before punctuation)
- Czech, Spanish, and others (because of special handling for repeated dashes)
So this experiment is not a general solution, but raises other questions on how the various Unicode segmenters work in SILE.
Parameters:
- self Instance pointer
- item table The item to handle