Can't change creator type with AppleScript

Question

I'm trying to change the file type and creator type of some files using AppleScript. I've found many examples telling me how to do it. My problem is, that no matter what I try, the creator type does not change. Yes, I can change the file type, but using the same syntax for the creator type fails to make any change. There is no error; rather, the creator type simply remains what it was before.
I'm doing this on 10.6.8, but I also tried it on 10.8.4 and had the same issue.
Here's an example script:
After executing on a single file (for example), the alerts show that the file type has been changed, but the creator type HAS NOT, and remains what it was previously.

Answer 1

Hello
Firstly, I have posted wrong handler, which should have been:
on set_creator_code(f, c)
        string f : POSIX path of target file
        string c : 4-character creator code (or "" to set 0x00000000)
    do shell script "/usr/bin/perl <<'EOF' - " & f's quoted form & " " & c's quoted form & "
die \"Usage: $0 <file> [<creator code>]\" unless @ARGV > 0;
my ($f, $c) = @ARGV;
(my $finfo = qx[xattr -p com.apple.FinderInfo \"$f\" 2>/dev/null]) =~ s/[[:space:]]//og;
$finfo = \"00\" x 32 unless $finfo;
my $cccc = unpack('H8', $c . \"\\0\\0\\0\\0\");
$finfo =~ s/ ^((?:..){4}) ((?:..){4}) /$1$cccc/ox;
qx[xattr -w -x com.apple.FinderInfo \"$finfo\" \"$f\"];
EOF"
end set_creator_code
* The previous (wrong) handler will create wrong data when there's no com.apple.FinderInfo attribute of the file. Sorry.
By the way, this handler is written to set creator code to \0\0\0\0 when c = "". So the script below will do what you want for a file.
set f to choose file
set_creator_code(f's POSIX path, "")
As for recursive processing, it is straightforward but the question is how to determine the target files. Processing every file under a given directory tree could be too broad and potentially dangerous. Can we assume the target files are all html and its name extension is .html or .htm? If so, the script below will do what you want:
set d to choose folder
set_creator_code_recursively(d's POSIX path, "(html|htm)", "")
on set_creator_code_recursively(d, e, c)
        string d : POSIX path of target directory
        string e : name extension pattern (case insensitive), e.g., (html|htm|css)
        string c : 4-character creator code (or "" to set 0x00000000)
    do shell script "/usr/bin/perl <<'EOF' - " & d's quoted form & " " & e's quoted form & " " & c's quoted form & "
die \"Usage: $0 <directory> <name extension pattern> [<creator code>]\" unless @ARGV > 1;
my ($dir, $ext, $code) = @ARGV;
local $/=\"\\0\";
my @ff = map {chomp; $_} qx[find -E \"$dir\" -type f -iregex '.*\\\\.$ext\\$' -print0];
for my $f (@ff) {
    (my $finfo = qx[xattr -p com.apple.FinderInfo \"$f\" 2>/dev/null]) =~ s/[[:space:]]//og;
    $finfo = \"00\" x 32 unless $finfo;
    my $cccc = unpack('H8', $code . \"\\0\\0\\0\\0\");
    $finfo =~ s/ ^((?:..){4}) ((?:..){4}) /$1$cccc/ox;
    qx[xattr -w -x com.apple.FinderInfo \"$finfo\" \"$f\"];
EOF"
end set_creator_code_recursively
Hope this may help,
H