file - perl6 IO::Handle没有printf方法，与文档不一致，或者我错过了什么？

Question

我正在尝试打开一个文件进行写入，并使用printf进行格式化，但是文档和实际情况似乎并不相同。我想念什么吗？

To exit type 'exit' or '^D'
> my $fh=open "test", :w;
IO::Handle<"test".IO>(opened, at octet 0)
> $fh.printf: "test";
No such method 'printf' for invocant of type 'IO::Handle'
  in block <unit> at <unknown file> line 1

但是根据文档，我的代码似乎还可以:

https://docs.perl6.org/routine/printf

非常感谢你 !!

Answer 1

the docs中的printf()示例对我也不起作用:

~/p6_programs$ perl6 -v
This is Rakudo version 2016.11 built on MoarVM version 2016.11
implementing Perl 6.c.

~/p6_programs$ cat 4.pl6 
my $fh = open 'outfile.txt', :w;
$fh.printf: "The value is %d\n", 32;
$fh.close;

~/p6_programs$ perl6 4.pl6 
No such method 'printf' for invocant of type 'IO::Handle'
  in block <unit> at 4.pl6 line 3

您可以使用 sprintf()作为解决方法:

my $fh = open 'outfile.txt', :w;
$fh.say: sprintf "The value is %d", 32;
$fh.close;

或 fmt():

my $fh = open 'outfile.txt', :w;
$fh.say: 32.fmt("The value is %d");
$fh.close;