extract example based on .modified unless --force

Author: gfldex

util/extract-examples.p6

@@ -40,7 +40,7 @@ multi sub walk(Str $s is copy, @context) {
 
 my &verbose = sub (|c) {};
 
-sub MAIN(Str :$source-path!, Str :$prefix!, Str :$exclude = ".git", Bool :v(:verbose($v)), *@files) {
+sub MAIN(Str :$source-path!, Str :$prefix!, Str :$exclude = ".git", Bool :v(:verbose($v)), Bool :$force, *@files) {
     my \exclude = none(flat <. ..>, $exclude.split(','));
 
     @files ||= gather for $source-path {
@@ -52,6 +52,8 @@ sub MAIN(Str :$source-path!, Str :$prefix!, Str :$exclude = ".git", Bool :v(:ver
 
     for @files».IO -> $file {
         my $out-file-path = IO::Path.new($prefix ~ $file.abspath.substr($source-path.IO.abspath.chars, $file.abspath.chars - $source-path.IO.abspath.chars - 5) ~ '.p6');
+        next if !$force && $out-file-path.f && $file.modified < $out-file-path.modified;
+
         mkdir $out-file-path.volume ~ $out-file-path.dirname;
         $*OUT = open($out-file-path, :w) // die "can not open $out-file-path";