From 0b076c8def3309301312674b9f136613a3827394 Mon Sep 17 00:00:00 2001
From: Amr Gharbeia <amr@gharbeia.net>
Date: Mon, 18 May 2026 15:48:15 -0400
Subject: [PATCH] v1.0.0: add char-width and search-highlight to cl-tty library
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char-width → cl-tty.box (text.lisp): terminal column width for Unicode
  characters including CJK, emoji, combining marks, and tab.

search-highlight → cl-tty.markdown: wraps query matches in **bold**
  markers for search result emphasis. Pure function, zero dependencies.
---
 org/box-renderable.org    | 30 ++++++++++++++++++++++++++++++
 org/markdown-renderer.org | 25 +++++++++++++++++++++++++
 org/package.org           |  2 +-
 3 files changed, 56 insertions(+), 1 deletion(-)

diff --git a/org/box-renderable.org b/org/box-renderable.org
index 049915a..6fbf00e 100644
--- a/org/box-renderable.org
+++ b/org/box-renderable.org
@@ -591,3 +591,33 @@ word list iteratively. Consecutive delimiters are collapsed
                    (setf start len))))
         finally (return (nreverse words))))
 #+END_SRC
+
+** char-width utility
+
+~char-width~ returns the terminal column width of a character.
+ASCII < 128 = 1. CJK, fullwidth, emoji = 2. Combining marks = 0.
+Tab = 8. Used by layout calculations that need to handle
+variable-width characters.
+
+#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/components/text.lisp
+(defun char-width (ch)
+  "Returns the terminal column width of character CH."
+  (let ((code (char-code ch)))
+    (cond
+      ((= code 9) 8)
+      ((< code 32) 0)
+      ((<= code 127) 1)
+      ((<= #x4E00 code #x9FFF) 2)
+      ((<= #x3400 code #x4DBF) 2)
+      ((<= #x3040 code #x309F) 2)
+      ((<= #x30A0 code #x30FF) 2)
+      ((<= #xAC00 code #xD7AF) 2)
+      ((<= #xFF01 code #xFF60) 2)
+      ((<= #xFFE0 code #xFFE6) 2)
+      ((<= #x1F300 code #x1F9FF) 2)
+      ((<= #x2600 code #x27BF) 2)
+      ((<= #x0300 code #x036F) 0)
+      ((<= #x20D0 code #x20FF) 0)
+      ((<= #xFE00 code #xFE0F) 0)
+      (t 1))))
+#+END_SRC
diff --git a/org/markdown-renderer.org b/org/markdown-renderer.org
index b144bd7..decf0b5 100644
--- a/org/markdown-renderer.org
+++ b/org/markdown-renderer.org
@@ -18,6 +18,7 @@ and diff rendering. Self-contained in ~cl-tty.markdown~ package.
    #:make-md-node #:md-node-p #:md-node-text
    #:parse-blocks #:parse-inline
    #:highlight-code
+   #:search-highlight
    #:classify-diff-line #:render-md #:render-md-node
    #:render-markdown #:render-inline
    #:apply-style #:apply-styles))
@@ -1062,6 +1063,30 @@ Returns an empty string for ~nil~ input.
             do (unless first (terpri s)) (princ part s)))))
 #+END_SRC
 
+*** search-highlight
+
+~search-highlight~ wraps occurrences of a query string in a text with
+**bold** markers for emphasis display. Case-insensitive matching.
+Returns the original text if query is nil or empty.
+
+#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/components/markdown.lisp
+(defun search-highlight (content query)
+  "Wrap occurrences of QUERY in CONTENT with **bold** markers."
+  (let ((lower-content (string-downcase content))
+        (lower-query (string-downcase query))
+        (result "") (pos 0))
+    (when (and query (> (length query) 0))
+      (loop
+        (let ((found (search lower-query lower-content :start2 pos)))
+          (unless found (return))
+          (setf result (concatenate 'string result
+                                   (subseq content pos found)
+                                   "**" (subseq content found (+ found (length query))) "**"))
+          (setf pos (+ found (length query)))))
+      (setf result (concatenate 'string result (subseq content pos)))
+      (if (string= result "") content result))))
+#+END_SRC
+
 * Tests
 
 The test suite covers parser edge cases, heading/paragraph parsing, inline
diff --git a/org/package.org b/org/package.org
index 3a51093..856d9ea 100644
--- a/org/package.org
+++ b/org/package.org
@@ -115,7 +115,7 @@ not be relied upon by application code outside of tests.
 
 #+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/components/package.lisp
    ;; Utilities (for tests)
-   #:word-wrap #:split-string
+   #:word-wrap #:split-string #:char-width
 #+END_SRC
 
 ** Dirty tracking