Groovy Regex problem

Answer 1

try

def illegalChars = ~/[\u0001-\u0008]|[\u000B-\u000C]|[\u000E-\u001F]|[\u007F-\u009F]/`

Answer 2

line 23:26: unexpected char: 0x0

This error message points to this part of the code:

def illegalChars = ~/[\u0000-...
12345678901234567890123

It looks like for some reason the compiler doesn't like having Unicode 0 character in the source code. That said, you should be able to fix this by doubling the slash. This prevents Unicode escapes at the source code level, and let the regex engine handle the unicode instead:

def illegals = ~/[\\u0000-\\u0008\\u000B\\u000C\\u000E-\\u001F\\u007F-\\u009F]/

Note that I've also combined the character classes into one instead of as alternates. I've also removed the range definition when they're not necessary.

References

• regular-expressions.info/Character Classes

---

On doubling the slash

Here's the relevant quote from java.util.regex.Pattern

Unicode escape sequences such as \u2014 in Java source code are processed as described in JLS 3.3. Such escape sequences are also implemented directly by the regular-expression parser so that Unicode escapes can be used in expressions that are read from files or from the keyboard. Thus the strings "\u2014" and "\\u2014", while not equal, compile into the same pattern, which matches the character with hexadecimal value 0x2014.

To illustrate, in Java:

System.out.println("\n".matches("\\u000A")); // prints "true"

However:

System.out.println("\n".matches("\u000A"));
// DOES NOT COMPILE!
// "String literal is not properly closed by a double-quote"

This is because \u000A, which is the newline character, is escaped in the second snippet at the source code level. The source code essentially becomes:

System.out.println("\n".matches("
"));
// DOES NOT COMPILE!
// "String literal is not properly closed by a double-quote"

This is not a legal Java source code.

Answer 3

OK here's my finding:

>>> print "XYZ".replaceAll(
       /[\\u0000-\\u0008\\u000B\\u000C\\u000E-\\u001F\\u007F-\\u009F]/,
       "-"
    )

---

>>> print "X\0YZ".replaceAll(
       /[\u0000-\u0008\u000B\u000C\u000E-\u001F\u007F-\u009F]/,
       "-"
    )

X-YZ

>>> print "X\0YZ".replaceAll(
       "[\\u0000-\\u0008\\u000B\\u000C\\u000E-\\u001F\\u007F-\\u009F]",
       "-"
    )

X-YZ

In other words, my \\uNNNN answer within /pattern/ is WRONG. What happens is that 0-\ becomes part of the range, and this includes <, > and all capital letters.

The \\uNNNN only works in "pattern", not in /pattern/.

I will edit my official answer based on comments to this "answer".

Related questions

• How to escape Unicode escapes in Groovy’s /pattern/ syntax