From 71bdb35d52747e6d7d9f55df4524d57c2966be94 Mon Sep 17 00:00:00 2001 From: "Jeffrey H. Kingston" Date: Tue, 14 Sep 2010 19:21:41 +0000 Subject: Lout 3.17. git-svn-id: http://svn.savannah.nongnu.org/svn/lout/trunk@2 9365b830-b601-4143-9ba8-b4a8e2c3339c --- doc/expert/pre_span | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 58 insertions(+) create mode 100644 doc/expert/pre_span (limited to 'doc/expert/pre_span') diff --git a/doc/expert/pre_span b/doc/expert/pre_span new file mode 100644 index 0000000..e527652 --- /dev/null +++ b/doc/expert/pre_span @@ -0,0 +1,58 @@ +@Section + @Title { "@StartHSpan","@StartVSpan", "@StartHVSpan", "@HSpan", and "@VSpan" } + @Tag { hspan } +@Begin +@PP +starthspan. @Index { @@StartHSpan symbol } +startvspan. @Index { @@StartVSpan symbol } +starthvspan. @Index { @@StartHVSpan symbol } +hspan. @Index { @@HSpan symbol } +vspan. @Index { @@VSpan symbol } +These symbols work together to produce spanning columns and rows in +a more flexible way than is possible in practice with @Code "//" and +{@Code "||"}. An object +@ID @Code "@StartHSpan object" +causes @Code object to be printed, but occupying all the horizontal space +to the right on the row mark on which it lies up to and including the rightmost +@@HSpan symbol on that mark not preceded by @@StartHVSpan, @@StartHSpan, +@@StartVSpan, or @@VSpan. The column mark of this spanning object is not +constrained to align with any of the column marks of the columns it spans. +@PP +If there is no @@HSpan symbol anywhere to the right of @@StartHSpan, then +the object spans only its own column. This means that it occupies that +column as usual but its mark is not constrained to align with those of the +other objects in the column. +@PP +Similarly, the @@StartVSpan symbol causes its object to occupy all +the vertical space below it on the column mark on which it lies, down to and +including the bottommost @@VSpan symbol on that mark not preceded by a +@@StartHVSpan, @@StartHSpan, @@StartVSpan, or @@HSpan; and if there +is no @@VSpan symbol anywhere below it on that mark, then the object +spans only its own row, occupying its row but with its mark not constrained +to align with the row mark. +@PP +The @@StartHVSpan symbol combines the effects of @@StartHSpan and +@@StartVSpan, allowing an object to span both columns and rows +simultaneously. For example, in +@ID @Code { +"@StartHVSpan x | | @HSpan" +"/" +"@VSpan | |" +} +the object @Code x will occupy a rectangular area spanning three columns, +two rows, and the gaps between them. +@PP +The objects lying in the region spanned should all be empty, or the +@@HSpan and @@VSpan symbols can be used to document the spanning that +is occurring. At present there may be no galley targets or recursive symbols +within the right parameter of @@StartHSpan, @@StartVSpan, or +@@StartHVSpan. However, the right parameter may otherwise be an +arbitrary object, including paragraphs of text that require breaking. +@PP +If the right parameter of @@StartHSpan, @@StartVSpan, or @@StartHVSpan +occupies more horizontal or vertical space than all of the spanned columns +or rows combined require, the extra space goes into the last spanned column +or row. Overlapping spanning rows and columns are permitted. Gaps spanned +by span objects are unbreakable (their @Code "u" indicator is set +automatically and cannot be revoked). +@End @Section -- cgit