在文本模式下在单个字符后添加不间断空格

Question

是否可以在 LaTeX (2e) 中创建宏或其他处理命令，在文本模式下在单个字符后添加不间断空格？

例子：

A new example here will add a "tilde", after single letter, but will skip math mode.
$12 \times A = 128$

应产生：

A~new example here will add a~"tilde", after single letter, but will skip math mode.
$12 \times A = 128$

我知道我可以使用类似这样的正则表达式：s/\(\<[a-z]\>\)[ ]/\1\~/g，但是这个也会在数学模式和列表/逐字模式下改变文本。

Answer 1

在 TeX 中执行此操作会有点脆弱：我会按照您的建议在编辑器中使用正则表达式进行替换。（如果您只想~在文本中创建一个并在数学中创建一个普通空格，这会更容易，但让它在列表和逐字中工作会更难）

例如给定

\documentclass{article}

\usepackage{amsmath}

\begin{document}

A new example here will add a "tilde", after single letter, but will skip math mode.
$12 \times A = 128$
\[ a b c = 123\]
and a bit nore text
\begin{align}
a &= b\\
x & = y 
\end{align}

\begin{verbatim}
A new example here will add a "tilde", after single letter,
but will skip math mode.
$12 \times A = 128$
\[ a b c = 123\]
and a bit nore text
\begin{align}
a &= b\\
x & = y 
\end{align}
\end{verbatim}


A new example here will add a "tilde", after single letter, but will skip math mode.
$12 \times A = 128$
\[ a b c = 123\]
and a bit nore text
\begin{align}
a &= b\\
x & = y 
\end{align}

\begin{verbatim}
A new example here will add a "tilde", after single letter,
but will skip math mode.
$12 \times A = 128$
\[ a b c = 123\]
and a bit nore text
\begin{align}
a &= b\\
x & = y 
\end{align}
\end{verbatim}

\end{document}

M-x addtildeemacs 中的命令产生

\documentclass{article}

\usepackage{amsmath}

\begin{document}

A~new example here will add a~"tilde", after single letter, but will skip math mode.
$12 \times A = 128$
\[ a b c = 123\]
and a~bit nore text
\begin{align}
a &= b\\
x & = y 
\end{align}

\begin{verbatim}
A new example here will add a "tilde", after single letter,
but will skip math mode.
$12 \times A = 128$
\[ a b c = 123\]
and a bit nore text
\begin{align}
a &= b\\
x & = y 
\end{align}
\end{verbatim}


A~new example here will add a~"tilde", after single letter, but will skip math mode.
$12 \times A = 128$
\[ a b c = 123\]
and a~bit nore text
\begin{align}
a &= b\\
x & = y 
\end{align}

\begin{verbatim}
A new example here will add a "tilde", after single letter,
but will skip math mode.
$12 \times A = 128$
\[ a b c = 123\]
and a bit nore text
\begin{align}
a &= b\\
x & = y 
\end{align}
\end{verbatim}

\end{document}

其中addtilde定义为

(defun hidespaceenv (e)
  (goto-char (point-min))
  (while (re-search-forward 
      (if (string-equal e "[") "\\\\\\["
        (if (string-equal e "$") "\\$"
          (concat "\\\\begin{" e "}")))
      nil 1)
    (while (re-search-forward "\\([a-zA-Z]\\)\\(\\s-+\\)\\|\\(\\\\begin\\)" (save-excursion(re-search-forward 
                                  (if (string-equal e "[") "\\\\\\]"
                                    (if (string-equal e "$") "\\$"
                                      (concat "\\\\end{" e "}")))
                                  nil 1) (point)) 1)
      (replace-match "\\1SPACE@@\\2\\3@@" t))))

(defun addtilde ()
  (interactive)
  (mapcar `hidespaceenv (list "verbatim" "align" "equation" "[" "$"))
  (goto-char (point-min))
  (while (re-search-forward "\\(\\(^\\|\\s-+\\)[a-zA-Z]\\)\\s-+" nil 1)
    (replace-match "\\1~"))
  (goto-char (point-min))
  (while (re-search-forward "SPACE@@\\(\\s-+\\|\\\\begin\\)@@" nil 1)
    (replace-match "\\1")))