所以我有一堆LaTeX风格的文档，一个看起来像这样......
\documentclass{article}
\usepackage{amsmath, amssymb, amsthm}
\begin{document}
{\Large \begin{center} Homework Problems \end{center}}\begin{itemize}\item\end{itemize}
\begin{enumerate}
\item Prove: For all sets $A$ and $B$, $(A - B) \cup
(A \cap B) = A$.
\begin{proof}
\begin{align}
& (A - B) \cup (A \cap B) && \\
& = (A \cap B^c) \cup (A \cap B) && \text{by
Alternate Definition of Set Difference} \\
& = A \cap (B^c \cup B) && \text{by Distributive Law} \\
& = A \cap (B \cup B^c) && \text{by Commutative Law} \\
& = A \cap U && \text{by Union with the Complement Law} \\
& = A && \text{by Intersection with $U$ Law}
\end{align}
\end{proof}
\item If $n = 4k + 3$, does 8 divide $n^2 - 1$?
\begin{proof}
Let $n = 4k + 3$ for some integer $k$. Then
\begin{align}
n^2 - 1 & = (4k + 3)^2 - 1 \\
& = 16k^2 + 24k + 9 - 1 \\
& = 16k^2 + 24k + 8 \\
& = 8(2k^2 + 3k + 1) \text{,}
\end{align}
which is certainly divisible by 8.
\end{proof}
\end{enumerate}
\end{document}
现在首先我必须阅读每个文档和行，找到所有“\ begin {BLOCK}”和“\ end {BLOCK}”命令，并将BLOCK字符串添加到堆栈中，当我找到匹配的“ \ end“我会在我的堆栈上调用pop（）命令。我完成了所有这些，它只是没有很好的组织，或者至少我认为有一个更好的方式去做它比我所有的“if”语句。所以这是我的第一个问题，是否有比我做的更好的事情？
接下来我想查找错误并报告错误。例如，如果我从上面的文本中删除了“\ begin {document}”行，我希望程序能够运行，执行它想要的所有操作，但是当它到达“\ end {document}”行时，它会报告缺少“\ begin”命令。我得到了我的代码来处理其他示例，例如删除枚举或逐项列出的“\ begin”命令，但我不能让这种情况起作用。
最后，我希望能够处理缺少的“\ end”命令。我已经尝试过了，但我不能完全正确地进行调节。假设我有这个文件......
\begin{argument}
\begin{Palin}No it can't. An argument is a connected series of statements intended to establish a proposition.\end{Palin}
\begin{Cleese}No it isn't.\end{Cleese}
\begin{Palin}\expression{exclamation}Yes it is! It's not just contradiction.\end{Palin}
\begin{Cleese}Look, if I argue with you, I must take up a contrary position.\end{Cleese}
\begin{Palin}Yes, but that's not just saying \begin{quotation}'No it isn't.'\end{Palin}
\begin{Cleese}\expression{exclamation}Yes it is!\end{Cleese}
\begin{Palin}\expression{exclamation}No it isn't!\end{Palin}
\begin{Cleese}\expression{exclamation}Yes it is!\end{Cleese}
\begin{Palin}Argument is an intellectual process. Contradiction is just the automatic gainsaying of any statement the other person makes.\end{Palin}
\end{argument}
你会在第6行注意到有一个没有“\ end”的“\ begin {quotation}”命令。通过这个特定文档时我的代码将此作为输出...
PARSE ERROR Line 6: Missing command \begin{Palin}.
PARSING TERMINATED!
这显然不是真的，但我不知道如何重构我的错误处理以使这些情况起作用。有人可以提供任何帮助吗？特别是在组织此代码以更好地解决这些问题的过程中。
------------------------------------------- CODE --- ----------------------------------------
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.util.Scanner;
import java.util.Stack;
import java.util.StringTokenizer;
public class LaTeXParser{
public static void main(String args[]) throws FileNotFoundException{
Scanner scan = new Scanner(System.in);
Stack s = new Stack();
int lineCount = 0;
String line;
String nextData = null;
String title = null;
String fname;
System.out.print("Enter the name of the file (no extension): ");
fname = scan.next();
fname = fname + ".txt";
FileInputStream fstream = new FileInputStream(fname);
Scanner fscan = new Scanner(fstream);
System.out.println();
while(fscan.hasNextLine()){
lineCount++;
line = fscan.nextLine();
StringTokenizer tok = new StringTokenizer(line);
while(tok.hasMoreElements()){
nextData = tok.nextToken();
System.out.println("The line: "+nextData);
if(nextData.contains("\\begin") && !nextData.contains("\\end")){
if(nextData.charAt(1) == 'b'){
title = nextData.substring(nextData.indexOf("{") + 1, nextData.indexOf("}"));
s.push(title);
}
}//end of BEGIN if
if(nextData.contains("\\end") && !nextData.contains("\\begin")){
String[] theLine = nextData.split("[{}]");
for(int i = 0 ; i < theLine.length ; i++){
if(theLine[i].contains("\\end") && !s.isEmpty() && theLine[i+1].equals(s.peek())){
s.pop();
i++;
}
if(theLine[i].contains("\\end") && !theLine[i+1].equals(s.peek())){
System.out.println("PARSE ERROR Line " + lineCount + ": Missing command \\begin{" + theLine[i+1] + "}.");
System.out.println("PARSING TERMINATED!");
System.exit(0);
}
}
}//end of END if
if(nextData.contains("\\begin") && nextData.contains("\\end")){
String[] theLine = nextData.split("[{}]");
for(int i = 0 ; i < theLine.length ; i++){
if(theLine[i].contains("\\end") && theLine[i+1].equals(s.peek())){
s.pop();
}
if(theLine[i].equals("\\begin")){
title = theLine[i+1];
s.push(title);
}
}
}//end of BEGIN AND END if
}
}//end of whiles
fscan.close();
if(s.isEmpty()){
System.out.println();
System.out.println(fname + " LaTeX file is valid!");
System.exit(0);
}
while(!s.isEmpty()){
}
}
}