例如：
use Data::DPath ('dpath');
会工作但是
use Data::DPath;
惯于.
use WWW::Mechanize;
为什么？
解决方法
如果你是像WWW::Mechanize这样的类,那么你不需要导出任何函数.一切都是类或对象方法.我的$mech = WWW :: Mechanize-> new.
如果你是像strict那样的pragma,那么就没有函数也没有方法,它只是通过加载来完成它的工作.
默认情况下,某些模块导出太多函数.一个例子是Test::Deep,它出口……
all any array array_each arrayelementsonly arraylength arraylengthonly bag blessed bool cmp_bag cmp_deeply cmp_methods cmp_set code eq_deeply hash
hash_each hashkeys hashkeysonly ignore Isa isa listmethods methods noclass
none noneof num obj_isa re reftype regexpmatches regexponly regexpref
regexprefonly scalarrefonly scalref set shallow str subbagof subhashof
subsetof superbagof superhashof supersetof useclass
当另一个模块尝试导出相同的函数,或者如果您编写具有相同名称的函数时,问题就出现了.然后他们发生冲突,你会收到神秘的警告.
$cat ~/tmp/test.plx use Test::Deep; use List::Util qw(all); $perl -w ~/tmp/test.plx Subroutine main::all redefined at /Users/schwern/perl5/perlbrew/perls/perl-5.20.2/lib/5.20.2/Exporter.pm line 66. at /Users/schwern/tmp/test.plx line 2. Prototype mismatch: sub main::all: none vs (&@) at /Users/schwern/perl5/perlbrew/perls/perl-5.20.2/lib/5.20.2/Exporter.pm line 66. at /Users/schwern/tmp/test.plx line 2.
因此,不鼓励输出大量功能.例如,the Exporter documentation advises ……
Do not export method names!
Do not export anything else by default without a good reason!
Exports pollute the namespace of the module user. If you must export try to use @EXPORT_OK in preference to @EXPORT and avoid short or common symbol names to reduce the risk of name clashes.
不幸的是,有些模块太过分了. Data::DPath就是一个很好的例子.它有一个非常清晰的主函数dpath(),默认情况下它应该导出.否则它基本上没用.
您始终可以使用Some :: Module();关闭导出.