windows下安装inline::ruby模块出错

想在perl中内嵌ruby程序，于是下载了inline::ruby手动安装，一直提示“Could not find the ruby interpreter on your PATH. Stopping...”，原因找不到ruby的环境变量，但是ruyby已经安装好，系统环境变量已经添加好。找到makefile.pl中的相关代码如下：
#============================================================================
# What ruby are we going to run?
#============================================================================
my @rubies;
for $p (split /$Config{path_sep}/, $ENV{PATH}) {
    $p =~ s/^~/$ENV{HOME}/;
    $p .= "/ruby";
    push @rubies, { path => $p } if -f $p && -x $p;
}

unless (@rubies) {
    print "Could not find the ruby interpreter on your PATH. Stopping...\n";
    exit 1;
}

my $num = 1;
print "Found ${\(scalar @rubies)} ruby executables on your PATH.\n";
print $num++ . ". " . $_->{path} . "\n" for @rubies;

my $sel = prompt("Use which?", (scalar @rubies ? '1' : ()));
$sel = $rubies[$sel-1] if $sel =~ /^\d+$/;
$sel = { path => $sel } unless ref $sel eq 'HASH';

print "Using $sel->{path}\n";

实际在push @rubies, { path => $p } if -f $p && -x $p; 之前没有问题
高人指点一下push @rubies, { path => $p } if -f $p && -x $p;  什么意思？
哈哈 初学者 ！谢谢！