README
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hyphenation — go-typeset
Liang's hyphenation algorithm, in pure Go (no cgo, no dependencies.)
It answers one question: given a word, where may a hyphen fall? That is the method TeX uses, and it reads the same pattern files — the ones distributed for every language TeX supports. Extracted from go-tex/engine, where it feeds the paragraph builder.
How it works
A pattern carries priority digits between letters: hy3ph says a break after
hy scores 3. Every pattern matching any substring of the word (with . marking
a word boundary) contributes, the highest value at each position wins, and an
ODD value means a break is allowed there. \lefthyphenmin and \righthyphenmin
then forbid breaks too close to either end — 2 and 3 by default, which is why a
five-letter word is never hyphenated.
Use
import "github.com/go-typeset/hyphenation"
h := hyphenation.New()
for _, p := range patterns { // e.g. the lines of hyph-en-gb.pat.txt
h.AddPattern(p)
}
h.Points("hyphenation") // → [2 6]: hy-phen-ation
Each value t means a hyphen may follow the first t letters.
Tests
go test ./... — 100% statement coverage, run on six 64-bit architectures
(amd64, arm64, riscv64, loong64, ppc64le, s390x), three operating systems, and
both wasm targets.
Licence
BSD-3-Clause.
Documentation
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Index ¶
Constants ¶
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Variables ¶
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Functions ¶
This section is empty.
Types ¶
type Hyphenator ¶
type Hyphenator struct {
// contains filtered or unexported fields
}
Hyphenator holds the loaded patterns and the min-affix limits.
func New ¶
func New() *Hyphenator
func (*Hyphenator) AddPattern ¶
func (h *Hyphenator) AddPattern(p string)
addPattern parses one Liang pattern (e.g. "a1bc3d" or ".ach4") into its letter key and inter-letter value array (length = letters+1).
func (*Hyphenator) Mins ¶
func (h *Hyphenator) Mins() (left, right int)
Mins reports the current \lefthyphenmin and \righthyphenmin.
func (*Hyphenator) Points ¶
func (h *Hyphenator) Points(word string) []int
points returns the break positions in word: each value t means a hyphen is allowed after the first t letters (so between word[t-1] and word[t]).
func (*Hyphenator) SetMins ¶
func (h *Hyphenator) SetMins(left, right int)
SetMins sets \lefthyphenmin and \righthyphenmin: the number of letters that must remain before the first hyphen and after the last. TeX's defaults are 2 and 3, which is why it never hyphenates a five-letter word; a document (or a language's conventions) may want otherwise.
Source Files