ekp/ekp-hyphen.el
Kinneyzhang dc2f6da846 feat: visible-first lazy re-flow for large buffers; packaging polish
Buffers past ekp-auto-justify-lazy-threshold (20k chars) no longer
re-justify wholesale on a width change: the visible span updates
synchronously and the rest follows in polite background chunks
(run-with-timer ticks that yield to pending input).  Measured on a
300-paragraph, 132k-char article: perceived latency 332 ms → 15 ms,
background completion ~0.5 s.

Fixed in the process: adjacent chunk markers shared a boundary, and
the earlier chunk's delete+insert pushed the next chunk's start
marker back over the freshly inserted text — chunks grew linearly
(2.2k, 4.9k, 7.4k… chars) and background work went quadratic (14 s).
Start markers now use insertion-type t.  Regression test asserts the
chunked result equals the one-shot result property-for-property.

Also: org/markdown skip-face presets (ekp-region-org-skip-faces /
ekp-region-markdown-skip-faces), MELPA header hygiene (Version + URL
on the main file, stale Package-Requires dropped from ekp-hyphen.el),
readme notes.

67 ERT green; fuzz 300/300.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-26 23:23:25 +08:00

202 lines
7.8 KiB
EmacsLisp

;;; ekp-hyphen.el --- Liang hyphenation algorithm -*- lexical-binding: t; -*-
;; Copyright (C) 2024
;; Author: emacs-kp contributors
;; Keywords: text, hyphenation, typesetting
;;; Commentary:
;; Implementation of Frank Liang's hyphenation algorithm.
;; See: Liang, F.M. "Word Hy-phen-a-tion by Com-put-er" (1983)
;;
;; Usage:
;; (ekp-hyphen-load-languages "/path/to/dictionaries")
;; (setq h (ekp-hyphen-create "en_US"))
;; (ekp-hyphen-inserted h "hyphenation") ; => "hy-phen-ation"
;; (ekp-hyphen-boxes h "hyphenation") ; => ("hy" "phen" "ation")
;;; Code:
(require 'cl-lib)
;;; Data Structure
;; Single struct holds everything: patterns, cache, and margin constraints.
(cl-defstruct (ekp-hyphen (:constructor ekp-hyphen--create))
"Hyphenator object.
PATTERNS: hash-table, pattern-string -> (offset . priority-values).
CACHE: hash-table, word -> list of break positions.
MAXLEN: longest pattern length (bounds substring search).
LEFT/RIGHT: minimum chars before first / after last break."
patterns cache maxlen left right)
;;; Global State
(defvar ekp-hyphen--cache (make-hash-table :test 'equal)
"Cache: dictionary path -> compiled ekp-hyphen.")
(defvar ekp-hyphen--langs (make-hash-table :test 'equal)
"Registry: language code -> dictionary file path.")
(defvar ekp-hyphen--langs-short (make-hash-table :test 'equal)
"Fallback: short code (e.g., \"en\") -> first matching dict path.")
;;; Dictionary Loading
(defun ekp-hyphen-load-languages (dir)
"Scan DIR for .dic files, populate language registry."
(dolist (file (directory-files dir t "\\.dic\\'"))
(let* ((name (file-name-nondirectory file))
(lang (replace-regexp-in-string "\\(^hyph_\\|\\.dic$\\)" "" name))
(short (car (split-string lang "_"))))
(puthash lang file ekp-hyphen--langs)
(unless (gethash short ekp-hyphen--langs-short)
(puthash short file ekp-hyphen--langs-short)))))
(defun ekp-hyphen--resolve-lang (lang)
"Resolve LANG to dictionary path, trying exact then short forms."
(or (gethash lang ekp-hyphen--langs)
(let* ((norm (downcase (replace-regexp-in-string "-" "_" lang)))
(parts (split-string norm "_"))
found)
(while (and parts (not found))
(setq found (gethash (string-join parts "_")
ekp-hyphen--langs-short)
parts (butlast parts)))
found)))
;;; Pattern Compilation
(defun ekp-hyphen--parse-pattern (pat)
"Parse PAT like \"hy3ph\" into (letters offset . values).
Values array has length = letters + 1 (position after last letter).
E.g., \"a1bc2\" -> letters=\"abc\", values=(0 1 0 2)."
(let ((pos 0) (len (length pat)) letters values)
(while (< pos len)
;; Read optional digit (priority before next letter or at end)
(let ((digit 0))
(when (and (< pos len)
(>= (aref pat pos) ?0)
(<= (aref pat pos) ?9))
(setq digit (- (aref pat pos) ?0))
(cl-incf pos))
(push digit values)
;; Read letter if present
(when (and (< pos len)
(or (< (aref pat pos) ?0) (> (aref pat pos) ?9)))
(push (aref pat pos) letters)
(cl-incf pos))))
(setq letters (apply #'string (nreverse letters))
values (vconcat (nreverse values)))
;; Trim leading/trailing zeros
(let ((start 0) (end (length values)))
(while (and (< start end) (= (aref values start) 0)) (cl-incf start))
(while (and (> end start) (= (aref values (1- end)) 0)) (cl-decf end))
(when (> end start)
(list letters start (cl-subseq values start end))))))
(defun ekp-hyphen--compile (path)
"Compile dictionary at PATH into ekp-hyphen struct."
(let ((patterns (make-hash-table :test 'equal))
(maxlen 0))
(with-temp-buffer
(insert-file-contents path)
(forward-line 1) ; skip encoding line
(while (not (eobp))
(let* ((line (string-trim (buffer-substring-no-properties
(point) (line-end-position))))
(skip (or (string-empty-p line)
(string-match-p "^[%#]\\|HYPHENMIN" line)
(string-match-p "/" line)))) ; skip alt patterns
(unless skip
;; Handle ^^XX hex escapes
(setq line (replace-regexp-in-string
"\\^\\^\\([0-9a-fA-F]\\{2\\}\\)"
(lambda (m) (string (string-to-number
(match-string 1 m) 16)))
line))
(when-let ((parsed (ekp-hyphen--parse-pattern line)))
(puthash (car parsed) (cdr parsed) patterns)
(setq maxlen (max maxlen (length (car parsed)))))))
(forward-line 1)))
(ekp-hyphen--create :patterns patterns
:cache (make-hash-table :test 'equal)
:maxlen maxlen
:left 2 :right 2)))
;;; Hyphenation Algorithm
(defun ekp-hyphen--compute (h word)
"Compute break positions for WORD using hyphenator H."
(let* ((padded (concat "." (downcase word) "."))
(len (length padded))
(maxlen (ekp-hyphen-maxlen h))
(patterns (ekp-hyphen-patterns h))
(prio (make-vector (1+ len) 0)))
;; Apply matching patterns
(dotimes (i (1- len))
(cl-loop for j from (1+ i) to (min (+ i maxlen) len)
for pat = (gethash (substring padded i j) patterns)
when pat do
(let ((off (car pat)) (vals (cadr pat)))
(dotimes (k (length vals))
(let ((pos (+ i off k)))
(when (< pos (length prio))
(aset prio pos (max (aref prio pos)
(aref vals k)))))))))
;; Collect odd positions (subtract 1 for padding offset)
(let (result)
(dotimes (i (length prio))
(when (cl-oddp (aref prio i))
(push (1- i) result)))
(nreverse result))))
(defun ekp-hyphen--positions (h word)
"Get cached break positions for WORD."
(let* ((key (downcase word))
(cache (ekp-hyphen-cache h)))
(or (gethash key cache)
(puthash key (ekp-hyphen--compute h word) cache))))
;;; Public API
(defun ekp-hyphen-create (&optional lang file left right)
"Create hyphenator for LANG or dictionary FILE.
LEFT/RIGHT: min chars before/after breaks (default 2)."
(let ((path (or (and lang (ekp-hyphen--resolve-lang lang)) file)))
(unless path (error "No dictionary for: %s" lang))
(let ((h (or (gethash path ekp-hyphen--cache)
(puthash path (ekp-hyphen--compile path)
ekp-hyphen--cache))))
(if (or left right)
(ekp-hyphen--create :patterns (ekp-hyphen-patterns h)
:cache (ekp-hyphen-cache h)
:maxlen (ekp-hyphen-maxlen h)
:left (or left 2) :right (or right 2))
h))))
(defun ekp-hyphen-positions (h word)
"Return valid break positions in WORD, respecting margins."
(let ((left (ekp-hyphen-left h))
(right (- (length word) (ekp-hyphen-right h))))
(cl-remove-if-not (lambda (p) (and (>= p left) (<= p right)))
(ekp-hyphen--positions h word))))
(defun ekp-hyphen-inserted (h word &optional hyphen)
"Return WORD with HYPHEN inserted at break points."
(let ((hyphen (or hyphen "-")) (result word) (off 0))
(dolist (pos (ekp-hyphen-positions h word))
(setq result (concat (substring result 0 (+ pos off))
hyphen
(substring result (+ pos off)))
off (+ off (length hyphen))))
result))
(defun ekp-hyphen-boxes (h word)
"Split WORD into syllables at break points."
(split-string (ekp-hyphen-inserted h word " ") " "))
(provide 'ekp-hyphen)
;;; ekp-hyphen.el ends here