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author | Jeffrey H. Kingston <jeff@it.usyd.edu.au> | 2010-09-14 19:21:41 +0000 |
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committer | Jeffrey H. Kingston <jeff@it.usyd.edu.au> | 2010-09-14 19:21:41 +0000 |
commit | 71bdb35d52747e6d7d9f55df4524d57c2966be94 (patch) | |
tree | 480ee5eefccc40d5f3331cc52d66f722fd19bfb9 /hyph/README | |
parent | b41263ea7578fa9742486135c762803b52794105 (diff) | |
download | lout-71bdb35d52747e6d7d9f55df4524d57c2966be94.tar.gz |
Lout 3.17.
git-svn-id: http://svn.savannah.nongnu.org/svn/lout/trunk@2 9365b830-b601-4143-9ba8-b4a8e2c3339c
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diff --git a/hyph/README b/hyph/README new file mode 100644 index 0000000..84409bb --- /dev/null +++ b/hyph/README @@ -0,0 +1,124 @@ +Format of Lout hyphenation information files + +Jeffrey H. Kingston +22 December 1992 +21 September 1994 +6 June 1995 +3 April 1996 + +Basser Lout Version 3 incorporates automatic hyphenation using the +method introduced by TeX (see Appendix H of the TeXBook by D. E. Knuth), +with support for multilingual hyphenation. No special action is required +to install hyphenation unless it is desired to change the hyphenation +information that controls it. + +There is one hyphenation information file for each language, and it is +named in the langdef of that language. For example: + + langdef German Deutsch { german } + +(There will usually be other information between the hyphenation file +name and the closing brace, not relevant here.) This example means that +unpacked Lout hyphenation file german.lh or its packed equivalent +german.lp (see below) is to be used when hyphenating German words. These +files are kept in the Lout system hyphenation directory (this directory). If +a language is desired but no hyphenation information file is available, the +file name may be replaced with -, and then the language will be defined but +hyphenation in that language will never be attempted. Another possibility +is to include a placeholder file for the language (see below). + +The first time on any run that German hyphenation is required, Lout will +search the directories of the hyphenation path for a binary file called +german.lp, which contains a binary form of the hyphenation patterns in +german.lh, modified so that the file may be shared by big-endian and +little-endian machines. If german.lp cannot be found, Lout then searches +for the text file german.lh instead, and uses it to construct german.lp. +To change the German hyphenation patterns, delete german.lp and modify +german.lh; the rest is automatic. + +Alternatively, if lout is invoked with the -x flag and the langdef line +above appears in its input, it will read german.lh and produce german.lp +immediately. This is intended for setting up: it is good to create all +these packed files at setup time, since a subsequent lout run that needs them +will not have write permission in the Lout system hyphenation directory. + +An unpacked Lout hyphenation information (.lh) file mainly contains a +long list of TeX hyphenation patterns. It must begin with either + + Lout hyphenation information + +or + Lout hyphenation placeholder + +alone on the first line. In the second case, it is understood that the +file is a placeholder (i.e. a stub file which might be overwritten with +a real file in the future), and Lout does not read any futher; the effect +is that Lout will not hyphenate this language, but not complain about the +absence of the file either. + +In the non-placeholder case, following the header line comes the "Classes:" +heading followed by the character classes. For example: + + Classes: + @!$%^&*()_-+=~`{[}]:;'|<,.>?/0123456789 + aA + bB + cC + ... + yY + zZ + +The hyphenation process treats the characters in each class as identical +(so the classes above ensure that the distinction between upper and lower +case is ignored). By definition, the characters of the first class are +"non-letters", and the characters of the remaining classes are "letters". +Notice that these are actual characters, not character names: hyphenation +files are encoding-specific. + +Next comes the "Exceptions:" heading followed by the exceptions, which +are words (composed of letters and "-" only) whose hyphenation is to be +treated as a special case. For example: + + Exceptions: + ta-ble + phil-an-thropic + +These words may be hyphenated in the places shown by the "-" characters. +Character classes are in effect here (Table will be hyphenated as Ta-ble). +If there are no exceptions, "Exceptions:" may be omitted. + +Next comes an optional LengthLimit section, which tells Lout to ignore +some patterns. For example, + + LengthLimit: + 4 + +means that patterns containing more than 4 letters (note that +. counts as a letter) are to be ignored. The purpose is to discard +the least important patterns from files that are too large for Lout +to handle otherwise. None of the files actually use this at present, +but hyphenation files seem to be getting larger and larger, and if +any whoppers come along they might have to be trimmed in this way. + +Finally comes the "Patterns:" heading followed by the list of TeX +hyphenation patterns. Apart from the weighting digits, the patterns +should contain only letters. Lout understands some TeX escape sequences +e.g. it will accept \^e anywhere in a hyphenation file as the ecircumflex +character. + +The file may contain comments, which begin with % (either at the start +of a line or after a white space character) and go to end of line. The +headings, classes, exceptions and patterns are separated by arbitrary +white space. + +Briefly, hyphenation of a word works like this. If the word contains a +character not found in any character class, it will not be hyphenated. +Otherwise the word is analysed into sequences of letters separated by +sequences of non-letters. Each sequence of five or more letters is +then matched, either with an exception or else with the hyphenation +patterns, and hyphenated. The hyphen character "-" is treated specially. + +Extreme lengths were resorted to to compress the .lp file as much as +possible. Files significantly larger than german.lh are likely to cause +Lout to abort with an error message. Please contact jeff@cs.su.oz.au if +you have problems with this or anything else. |