--- name: "patgen" section: "1" platform: "linux" package: "texlive-doc" version: "2026.1-1" release: "Arch Linux 2026-11-01" platforms: ["linux"] url: "https://new.carta.tech/patgen" --- # patgen(1) generate patterns for TeX hyphenation ## 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)](/initex/1.md) 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