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  1. /* package whatever; // don't place package name! */
  2.  
  3. import java.util.*;
  4. import java.lang.*;
  5. import java.io.*;
  6. import java.util.ArrayList;
  7. import java.util.regex.Matcher;
  8. import java.util.regex.Pattern;
  9.  
  10. /* Name of the class has to be "Main" only if the class is public. */
  11. class Ideone
  12. {
  13. 	public static void main (String[] args) throws java.lang.Exception
  14. 	{
  15. 		String source = "\\begin\\{theorem\\} Hello, World! \\end\\{theorem\\}";
  16.     	LatexTheoremProofExtractor extractor = new LatexTheoremProofExtractor(source);
  17.     	extractor.parse();
  18.     	ArrayList<String> theorems = extractor.getTheorems();
  19. 	    System.out.println(theorems.get(0).trim());
  20. 	    System.out.println("Hello, World!");
  21. 	}
  22. }
  23. class LatexTheoremProofExtractor {
  24.  
  25.     // This is the LaTeX source that will be processed
  26.     private String source = null;
  27.  
  28.     // These are the list of theorems and proofs that are extracted, respectively 
  29.     private ArrayList<String> theorems = null;
  30.     private ArrayList<String> proofs = null;
  31.  
  32.     // These are the patterns to match theorems and proofs, respectively 
  33.     private static final Pattern THEOREM_REGEX = Pattern.compile(Pattern.quote("\\begin\\{theorem\\}") + "(.+?)" + Pattern.quote("\\end\\{theorem\\}"));
  34.     private static final Pattern PROOF_REGEX = Pattern.compile(Pattern.quote("\\begin\\{proof\\}") + "(.+?)" + Pattern.quote("\\end\\{proof\\}"));
  35.  
  36.     LatexTheoremProofExtractor(String source) {
  37.         this.source = source;
  38.     }
  39.  
  40.     public void parse() {
  41.         extractEntity("theorem");
  42.         extractEntity("proof");
  43.     }
  44.  
  45.     private void extractTheorems() {
  46.         if(theorems != null) {
  47.             return;
  48.         }
  49.  
  50.         theorems = new ArrayList<String>();
  51.  
  52.         final Matcher matcher = THEOREM_REGEX.matcher(source);
  53.         while (matcher.find()) {
  54.             theorems.add(new String(matcher.group(1)));
  55.         }   
  56.     }
  57.  
  58.     private void extractProofs() {
  59.         if(proofs != null) {
  60.             return;
  61.         }
  62.  
  63.         proofs = new ArrayList<String>();
  64.  
  65.         final Matcher matcher = PROOF_REGEX.matcher(source);
  66.         while (matcher.find()) {
  67.             proofs.add(new String(matcher.group(1)));
  68.         }       
  69.     }
  70.  
  71.     private void extractEntity(final String entity) {   
  72.         if(entity.equals("theorem")) {
  73.             extractTheorems();
  74.         } else if(entity.equals("proof")) {
  75.             extractProofs();
  76.         } else {
  77.             // TODO: Throw an exception or something
  78.         }       
  79.     }
  80.  
  81.     public ArrayList<String> getTheorems() {
  82.         return theorems;
  83.     }
  84.  
  85. }
Success #stdin #stdout 0.1s 320512KB
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Standard input is empty
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Hello, World!
Hello, World!
https://ideone.com/Z1p64k
language:
Java (HotSpot 12)
created:
9 years ago
visibility:
secret

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