为什么语法'&name arg1 arg2 ...'不能用于调用Perl子例程？

Question

对于Perl子例程，如果传递0个参数，我可以使用4个形式调用它。但是如果传递1个或多个参数，有一种形式我不能使用，请参见下面:

sub name
{
    print "hellon";
}
# 4 forms to call
name;
&name;
name();
&name();
sub aname
{
        print "@_n";
}
aname "arg1", "arg2";
#&aname "arg1", "arg2"; # syntax error
aname("arg1", "arg2");
&aname("arg1", "arg2");

错误输出为

String found where operator expected at tmp1.pl line 16, near "&aname "arg1""
    (Missing operator before  "arg1"?)
syntax error at tmp1.pl line 16, near "&aname "arg1""
Execution of tmp1.pl aborted due to compilation errors.

有人能从编译器的角度解释错误输出吗?我不明白为什么它会抱怨缺少操作符。

谢谢

Answer 1

perlsub:

调用子程序:

       NAME(LIST);    # & is optional with parentheses.
       NAME LIST;     # Parentheses optional if predeclared/imported.
       &NAME(LIST);   # Circumvent prototypes.
       &NAME;         # Makes current @_ visible to called subroutine.

对于&NAME "arg", perl看到了&NAME() "ARG"，因此它认为在sub调用和"ARG"之间缺少一个操作符。

在Perl 5中，大多数情况下不需要&。