Merge pull request #179 from fglock/fix/exiftool-scalar-deref-and-hex-parsing

Fix ExifTool issues: scalar dereference autovivification and hexadecimal parsing

Author: fglock

src/main/java/org/perlonjava/parser/NumberParser.java

@@ -181,7 +181,13 @@ private static Node parseSpecialNumber(Parser parser, String initialPart, Number
                     exponentStr = String.valueOf(exponent);
                 }
             } else {
+                // Save token index for backtracking
+                int savedTokenIndex = parser.tokenIndex;
                 exponentStr = parseHexExponentTokens(parser);
+                if (exponentStr.isEmpty()) {
+                    // No exponent found, backtrack
+                    parser.tokenIndex = savedTokenIndex;
+                }
             }
         }
 
@@ -262,8 +268,9 @@ private static String parseHexExponentTokens(Parser parser) {
         if (parser.tokenIndex < parser.tokens.size() &&
                 parser.tokens.get(parser.tokenIndex).type == LexerTokenType.NUMBER) {
             exponentStr.append(cleanUnderscores(TokenUtils.consume(parser).text));
-        } else if (exponentStr.length() > 0) {
-            parser.throwError("Malformed hexadecimal floating-point exponent");
+        } else {
+            // Not a valid exponent - return empty string
+            return "";
         }
 
         return exponentStr.toString();

src/main/java/org/perlonjava/runtime/RuntimeScalar.java

@@ -1068,7 +1068,13 @@ public RuntimeScalar scalarDeref() {
         }
 
         return switch (type) {
-            case UNDEF -> throw new PerlCompilerException("Can't use an undefined value as a SCALAR reference");
+            case UNDEF -> {
+                // Autovivify: create a new scalar reference for undefined values
+                RuntimeScalar newScalar = new RuntimeScalar();
+                this.value = newScalar;
+                this.type = RuntimeScalarType.REFERENCE;
+                yield newScalar;
+            }
             case REFERENCE -> (RuntimeScalar) value;
             case STRING, BYTE_STRING ->
                     throw new PerlCompilerException("Can't use string (\"" + this + "\") as a SCALAR ref while \"strict refs\" in use");