Merge pull request #79 from sentrysoftware/feature/78-regexp-constant…

…-triggers-a-parserexception

Fixed issue #78 and parsing of regular expression constants (escaping)

src/main/java/org/sentrysoftware/jawk/frontend/AwkParser.java

@@ -417,13 +417,24 @@ private void readRegexp()
 		// should only contain nothing or =, depending on whether
 		// starting with /... or /=...
 		assert regexp.length() == 0 || regexp.length() == 1;
-		while (c >= 0 && c != '\n' && (c != '/' || (regexp.length() > 0 && regexp.charAt(regexp.length() - 1) == '\\'))) {
-			regexp.append((char) c);
-			c = reader.read();
-			// completely bypass \r's
+		while (c >= 0 && c != '\n' && c != '/') {
+			if (c == '\\') {
+				c = reader.read();
+				if (c == '/') {
+					regexp.append('/');
+					c = reader.read();
+					continue;
+				} else if (c == '\\') {
+					regexp.append('\\');
+				}
+			}
 			while (c == '\r') {
 				c = reader.read();
 			}
+			if (c < 0 || c == '\n' || c == '/') break;
+
+			regexp.append((char) c);
+			c = reader.read();
 		}
 		if (c < 0 || c == '\n') {
 			throw new LexerException("Unterminated regular expression: " + regexp);

src/test/java/org/sentrysoftware/jawk/AwkParserTest.java

@@ -86,4 +86,10 @@ public void testOperatorPrecedence() throws Exception {
 		assertEquals("* precedes +", "5", evalAwk("1 + 2 * 2"));
 		assertEquals("+ precedes string concat", "33", evalAwk("1 + 2 3"));
 	}
+
+	@Test
+	public void testRegExpConstant() throws Exception {
+		assertEquals("/\\\\/ must be supported", "success", runAwk("/\\\\/ { printf \"success\" }", "a\\b"));
+		assertEquals("/\\// must be supported", "success", runAwk("/\\// { printf \"success\" }", "a/b"));
+	}
 }