删除跨多行的LaTeX宏

Question

我有一段LaTeX代码，想要去掉所有的\NEW{"跨多行的文本"}。这里的"跨多行的文本"要保留，只需要去掉"\NEW{"和文件中某个地方的"}"，而大括号里的内容要保持不变。制表符、空格和换行也要保留。我之前尝试写了一个Python程序，但输出效果不太理想。最难的部分是去掉大括号的地方（有可能在下一行）。

输入：

\chapter{A \NEW{very} small \NEW{chapter}}

\begin{itemize}
    \item \NEW{Bla}
    \item Dusse
    \item Mekker
\end{itemize}

\NEW{This is new
    multiline \texttt{text} with some things \TBD{TBD} in between
  } The end

输出（预期）：

\chapter{A very small chapter}

\begin{itemize}
    \item Bla
    \item Dusse
    \item Mekker
\end{itemize}

This is new
    multiline \texttt{text} with some things \TBD{TBD} in between
   The end

我自己写的有效的Python解决方案：

• 读取一行
  • 把\NEW{的出现替换成一个标记（字符0xff）
  • 逐个读取行中的字符c
    • 检查c是否是标记，如果是，就设置marked为True，并为嵌套的大括号设置marked_cnt，读取下一个字符
    • 否则检查：如果c是'{'，就增加marked_cnt
    • 否则检查：如果c是'}'并且marked为True，就减少marked_cnt
    • 如果marked_cnt等于-1，重置marked为False，marked_cnt为0，读取下一个字符
    • 打印“有效”的字符

    #!/usr/bin/env python2.7
    import sys

    marker=chr(255)
    marked=False
    marked_cnt=0

    fin = open("file.tex", "r")
    fout = open("file.tex.out", "w")

    for line in fin:
        l = line.replace("\NEW{", marker)
        for c in l:
            if c == marker:
                marked = True
                marked_cnt = 0
                continue
            elif c == '{':
                marked_cnt += 1
            elif ((c == '}') and
                (marked == True)):
                marked_cnt -= 1

            if marked_cnt == -1:
                marked = False
                marked_cnt = 0
                continue

            fout.write(c)

    fin.close()
    fout.close()

Answer 1

试试用正则表达式：

import re
myRe = re.compile(r'\\NEW{\w+}')
for match in myRe.findall(myString):
    newstring = match.replace('\NEW{','')
    newstring = newstring.replace('}','')
    myString.replace(match,newstring)

不过，这样做还解决不了多行的问题。要解决这个问题，可以直接遍历字符串，检查括号的开和关：

while s.find('\\NEW{')>-1:
    position = s.find('\\NEW{')
    print(position, s[position:position+4])
    s = s[0:position]+s[position+5:]
    trailexist = True
    openbrackets = 0

    while trailexist and position<len(s):
        position +=1
        print(len(s), position,s[position])
        if s[position] == '}' and openbrackets == 0:
            s = s[:position]+s[position+1:]
            trailexist = False
            print("Removed!", position)
        elif s[position] == '{':
            openbrackets += 1
            print('Openbrackets:',openbrackets)
        elif s[position] == '}' and openbrackets>0:
            openbrackets -= 1