patgen(1) General Commands Manual patgen(1)
NAME
patgen - generate patterns for TeX hyphenation
SYNOPSIS
patgen dictionary_file pattern_file patout_file translate_file
DESCRIPTION
The patgen program reads a dictionary_file containing a list of
hyphenated words and a pattern_file containing previously-generated
patterns (if any) for a particular language (not a complete TeX source
file; see below), and produces the patout_file with (previously- plus
newly-generated) hyphenation patterns for that language. The
translate_file defines language specific values for the parameters
left_hyphen_min and right_hyphen_min used by TeX's hyphenation
algorithm and the external representation of the lower and upper case
version(s) of all `letters' of that language. Further details of the
pattern generation process such as hyphenation levels and pattern
lengths are requested interactively from the user's terminal.
Optionally, patgen creates a new dictionary file pattmp.n showing the
good and bad hyphens found by the generated patterns, where n is the
highest hyphenation level.
The patterns generated by patgen can be read by initex(1) for use in
hyphenating words. For the original example of patgen's output, see (in
TeX Live) $TEXMFMAIN/tex/generic/hyphen/hyphen.tex, which contains the
patterns TeX uses for English by default. In TeX Live, patterns for
(many) other languages are available (unless chosen not to be
installed).
All filenames must be complete; no adding of default extensions or path
searching is done.
FILE FORMATS
Letters
When initex digests hyphenation patterns, TeX first expands macros
and the result must entirely consist of digits (hyphenation levels),
dots (`.', meaning the edge of a word), and letters. In pattern files
for non-English languages letters are often represented by macros or
other expandable constructs. For the purpose of patgen these are just
character sequences, subject to the condition that no such sequence
is a prefix of another one.
Dictionary file
A dictionary file contains a weighted list of hyphenated words, one
word per line, each starting in column 1. A digit in column 1
indicates a global word weight (initially =1) applicable to all
following words up to the next global word weight. A digit at some
intercharacter position indicates a weight for that position only.
The hyphens in a word are indicated by `-', `*', or `.' (or their
replacements as defined in the translate file) for hyphens yet to be
found, `good' hyphens (correctly found by the patterns), and `bad'
hyphens (erroneously found by the patterns) respectively; when
reading a dictionary file `*' is treated like `-' and `.' is ignored.
Pattern file
A pattern file contains only patterns in the format above, e.g., from
a previous run of patgen. It may not contain any TeX comments or
control sequences. For instance, this is not a valid pattern file:
% this is an invalid pattern file for TeX.
\patterns{%
...
}
Pattern files can only contain the actual patterns, i.e., the `...'.
Translate file
A translate file starts with a line containing the values of
left_hyphen_min in columns 1-2, right_hyphen_min in columns 3-4, and
either a blank or the replacement for one of the ``hyphen''
characters `-', `*', and `.' in columns 5, 6, and 7. Input lines are
extended with blanks as for many TeX related programs.
Each following line defines one `letter': an arbitrary delimiter
character in column 1, followed by one or more external
representations of that character (first the `lower' case one used
for output), each one terminated by the delimiter and the whole
sequence terminated by another delimiter.
If the translate file is empty, the default values are
left_hyphen_min=2, right_hyphen_min=3, and the 26 lower case letters
a...z with their upper case representations A...Z.
Terminal input
After reading the translate_file and any previously-generated
patterns from pattern_file, patgen requests input from the user's
terminal.
First the integer values of hyph_start and hyph_finish, the lowest
and highest hyphenation level for which patterns are to be generated.
The value of hyph_start should be larger than any hyphenation level
already present in pattern_file.
Then, for each hyphenation level, the integer values of pat_start and
pat_finish, the smallest and largest pattern length to be analyzed,
as well as good weight, bad weight, and threshold, the weights for
good and bad hyphens and a weight threshold for useful patterns.
Finally the decision (`y' or `Y' vs. anything else) whether or not to
produce a hyphenated word list.
FILES
$TEXMFMAIN/tex/generic/hyphen/hyphen.tex
The original hyphenation patterns for English, by Donald Knuth and
Frank Liang.
$TEXMFMAIN/tex/generic/hyphen/zerohyph.tex
A pattern file with no patterns, for languages that don't use
hyphenation.
SEE ALSO
Frank Liang and Peter Breitenlohner, patgen.web.
Frank Liang, Word hy-phen-a-tion by com-puter, STAN-CS-83-977, Stanford
University Ph.D. thesis, 1983, http://tug.org/docs/liang.
Donald E. Knuth, The TeXbook, Addison-Wesley, Appendix H.
https://ctan.org/pkg/hyphenex
Hyphenation exceptions for American English, maintained by the
TUGboat editors, and used in TUGboat articles by default.
https://ctan.org/pkg/hyph-utf8
Collected hyphenation patterns for many languages in many
formats.
https://ctan.org/pkg/ushyph
Large set of additional hyphenation patterns for English,
extended by Gerard Kuiken.
https://ctan.org/tex-archive/language/
General CTAN directory for patterns and support for many other
languages.
https://tug.org/TUGboat/Contents/listkeyword.html#CatTAGMultilingualDocumentProcessing
TUGboat articles on hyphenation and other aspects of language-
specific document processing.
AUTHORS
Frank Liang wrote the first version of this program. Peter
Breitenlohner made a substantial revision in 1991 for TeX 3. The first
version was published as the appendix to the TeXware technical report.
Howard Trickey originally ported it to Unix.
Public discussion list and bug reports: https://lists.tug.org/tex-k
Web2C 2026 10 January 2026 patgen(1)
texlive-bin 2026.78235 - Generated Thu Mar 5 16:02:15 CST 2026