Move things around, and start on new parser.

3 files changed, 122 insertions, 0 deletions

diff --git a/RGens/src/main/java/bjc/rgens/newparser/RGrammar.java b/RGens/src/main/java/bjc/rgens/newparser/RGrammar.java
new file mode 100644
index 0000000..9b47bd6
--- /dev/null
+++ b/RGens/src/main/java/bjc/rgens/newparser/RGrammar.java
@@ -0,0 +1,5 @@
+package bjc.rgens.newparser;
+
+public class RGrammar {
+
+}
diff --git a/RGens/src/main/java/bjc/rgens/newparser/RGrammarBuilder.java b/RGens/src/main/java/bjc/rgens/newparser/RGrammarBuilder.java
new file mode 100644
index 0000000..3b48a2a
--- /dev/null
+++ b/RGens/src/main/java/bjc/rgens/newparser/RGrammarBuilder.java
@@ -0,0 +1,7 @@
+package bjc.rgens.newparser;
+
+public class RGrammarBuilder {
+	public RGrammar toRGrammar() {
+		return null;
+	}
+}
diff --git a/RGens/src/main/java/bjc/rgens/newparser/RGrammarParser.java b/RGens/src/main/java/bjc/rgens/newparser/RGrammarParser.java
new file mode 100644
index 0000000..d60c6d4
--- /dev/null
+++ b/RGens/src/main/java/bjc/rgens/newparser/RGrammarParser.java
@@ -0,0 +1,110 @@
+package bjc.rgens.newparser;
+
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.LineNumberReader;
+import java.io.StringReader;
+import java.util.Scanner;
+
+/**
+ * Reads {@link RGrammar} from a input stream.
+ * 
+ * @author student
+ *
+ */
+public class RGrammarParser {
+	/**
+	 * The exception thrown when something goes wrong while parsing a grammar.
+	 * 
+	 * @author student
+	 *
+	 */
+	public static class GrammarException extends Exception {
+		/*
+		 * Serialization ID.
+		 */
+		private static final long serialVersionUID = -7287427479316953668L;
+
+		/**
+		 * Create a new grammar exception with the specified message.
+		 * 
+		 * @param msg
+		 *            The message for this exception.
+		 */
+		public GrammarException(String msg) {
+			super(msg);
+		}
+
+		/**
+		 * Create a new grammar exception with the specified message and cause.
+		 * 
+		 * @param msg
+		 *            The message for this exception.
+		 * 
+		 * @param cause
+		 *            The cause of this exception.
+		 */
+		public GrammarException(String msg, Exception cause) {
+			super(msg, cause);
+		}
+	}
+
+	/**
+	 * Read a {@link RGrammar} from an input stream.
+	 * 
+	 * @param is
+	 *            The input stream to read from.
+	 * 
+	 * @return The grammar represented by the stream.
+	 * 
+	 * @throws GrammarException
+	 *             Thrown if the grammar has a syntax error.
+	 */
+	public RGrammar readGrammar(InputStream is) throws GrammarException {
+		LineNumberReader lnReader = new LineNumberReader(new InputStreamReader(is));
+
+		try (Scanner scn = new Scanner(lnReader)) {
+			scn.useDelimiter("\\n\\.?\\n");
+
+			RGrammarBuilder build = new RGrammarBuilder();
+
+			while (scn.hasNext()) {
+				String block = scn.next();
+
+				if (block.startsWith("pragma")) {
+					handlePragmaBlock(block, build);
+				} else if (block.startsWith("[")) {
+					handleRuleBlock(block, build);
+				} else {
+					throw new GrammarException(String.format("Unknown block: %s", lnReader.getLineNumber(), block));
+				}
+			}
+		} catch (GrammarException gex) {
+			throw new GrammarException(String.format("Error at line %d", lnReader.getLineNumber()), gex);
+		}
+
+		return null;
+	}
+
+	private void handlePragmaBlock(String block, RGrammarBuilder build) throws GrammarException {
+		LineNumberReader lnReader = new LineNumberReader(new StringReader(block));
+
+		try (Scanner deblocker = new Scanner(lnReader)) {
+			deblocker.useDelimiter("\\n(?!\\t)");
+
+			while (deblocker.hasNext()) {
+				String pragma = deblocker.next();
+
+				if (!pragma.startsWith("pragma")) {
+					throw new GrammarException(String.format("Illegal line at line %d of pragma block: %s",
+							lnReader.getLineNumber(), pragma));
+				}
+			}
+		}
+	}
+
+	private void handleRuleBlock(String block, RGrammarBuilder build) {
+		// TODO Auto-generated method stub
+
+	}
+}