[06 - Top Down Parser] Fix 3 tests

- program00BeginEnd
- program01BeginEndMore
- program02BeginEnd2

ÜB-Praxis-Abstiegsparser für X-Leer/src/de/dhbw/compiler/xparser/XParser.java

@@ -12,15 +12,163 @@
 package de.dhbw.compiler.xparser;
 
 public class XParser {
-
+	private final TokenReader in;
 
 	public XParser(TokenReader in) {
-		//TODO Initialization
+		this.in = in;
 	}
 
 	public Tree parseProgram() {
-		//TODO Parser
+		int oldPosition = in.getPosition();
+		Tree program, id, semicolon, block, dot, eof;
+
+		if ((program = parseToken(Token.PROGRAM)) != null
+			&& ((id = parseToken(Token.ID)) != null)
+			&& ((semicolon = parseToken(Token.SEMICOLON)) != null)
+			&& ((block = parseBlock()) != null)
+			&& ((dot = parseToken(Token.DOT)) != null)
+			&& ((eof = parseToken(Token.EOF)) != null)) {
+			Tree tree = new Tree(new Token(Token.APROGRAM));
+			tree.addLastChild(program);
+			tree.addLastChild(id);
+			tree.addLastChild(semicolon);
+			tree.addLastChild(block);
+			tree.addLastChild(dot);
+			tree.addLastChild(eof);
+
+			return tree;
+		}
+
+		System.out.println("> Skipping Tree");
+		in.setPosition(oldPosition);
 		return null;
 	}
 
+	private Tree parseBlock() {
+		int oldPosition = in.getPosition();
+
+		Tree begin, statList, end;
+		if ((begin = parseToken(Token.BEGIN)) != null
+			&& (statList = parseStatList()) != null
+			&& (end = parseToken(Token.END)) != null) {
+			Tree tree = new Tree(new Token(Token.BLOCK));
+			tree.addFirstChild(begin);
+			tree.addLastChild(statList);
+			tree.addLastChild(end);
+
+			return tree;
+		}
+
+		System.out.println("parseBlock> Skipping Tree");
+		in.setPosition(oldPosition);
+		return null;
+	}
+
+	private Tree parseStatList() {
+		// int oldPosition = in.getPosition();
+		Tree tree = new Tree(new Token(Token.STATLIST));
+		Tree stat;
+
+		while ((stat = parseStatWithSemicolon()) != null) {
+			tree.addLastChild(stat);
+		}
+
+//		if ((block = parseBlock()) != null) {
+//			tree.addFirstChild(new Tree(new Token(Token.STATWITHSEMI)));
+//			tree.addFirstChild(block);
+//			tree.addLastChild(new Tree(new Token(Token.SEMICOLON)));
+//
+//			return tree;
+//		}
+
+		// in.setPosition(oldPosition);
+		return tree;
+	}
+
+	private Tree parseStatWithSemicolon() {
+		int oldPosition = in.getPosition();
+		Tree tree = new Tree(new Token(Token.STATWITHSEMI));
+		Tree state, semicolon;
+
+		if (((state = parseStat()) != null)
+			&& ((semicolon = parseToken(Token.SEMICOLON)) != null)) {
+			tree.addLastChild(state);
+			tree.addLastChild(semicolon);
+			return tree;
+		}
+
+		in.setPosition(oldPosition);
+		return null;
+	}
+
+	private Tree parseStat() {
+		int oldPosition = in.getPosition();
+		Tree tree = new Tree(new Token(Token.STAT));
+		Tree numAssign, condStat, block;
+
+		if ((numAssign = parseNumAssign()) != null) {
+			tree.addLastChild(numAssign);
+			return tree;
+		}
+
+		in.setPosition(oldPosition);
+		if ((condStat = parseCondStat()) != null) {
+			tree.addLastChild(condStat);
+			return tree;
+		}
+
+		in.setPosition(oldPosition);
+		if ((block = parseBlock()) != null) {
+			tree.addLastChild(block);
+			return tree;
+		}
+
+		in.setPosition(oldPosition);
+		return null;
+	}
+
+	private Tree parseCondStat() {
+		return null;
+	}
+
+	private Tree parseNumAssign() {
+		int oldPosition = in.getPosition();
+		Tree tree = new Tree(new Token(Token.ASSIGNSTAT));
+		Tree id, assign, numExpr;
+
+		if ((id = parseToken(Token.ID)) != null
+			&& (assign = parseToken(Token.ASSIGN)) != null
+			&& (numExpr = parseNumExpr()) != null) {
+			tree.addLastChild(id);
+			tree.addLastChild(assign);
+			tree.addLastChild(numExpr);
+			return tree;
+		}
+
+		in.setPosition(oldPosition);
+		return null;
+	}
+
+	private Tree parseNumExpr() {
+		int oldPosition = in.getPosition();
+		Tree tree = new Tree(new Token(Token.EXPR));
+
+
+
+		return null;
+	}
+
+	private Tree parseToken(int tokenType) {
+		int oldPosition = in.getPosition();
+		Token nextToken = in.nextToken();
+		System.out.println("parseToken> " + nextToken);
+		if (nextToken.getType() == tokenType) {
+			return new Tree(nextToken);
+		} else {
+			// Reset to last position as it needs to be re-read again
+			in.setPosition(oldPosition);
+			return null;
+		}
+	}
+
 }

ÜB-Praxis-Abstiegsparser für X-Leer/src/de/dhbw/compiler/xparser/XParserMain.java

@@ -12,7 +12,7 @@ package de.dhbw.compiler.xparser;
 
 import java.io.PrintWriter;
 import java.io.StringReader;
-
+import java.util.Scanner;
 
 
 public class XParserMain {
@@ -75,7 +75,12 @@ public class XParserMain {
 		//TODO Initialize scanner and parser
 		//TODO Call parser
 		//TODO Output: Tree, count of tokens and comparisons
-		
+		StringReader reader = new StringReader(BEISPIELFOLIEN);
+		JFlexXScanner scanner = new JFlexXScanner(reader);
+		TokenReader tokenReader = new TokenReader(scanner);
+		XParser parser = new XParser(tokenReader);
+
+		parser.parseProgram();
 	}
 
 }