全局符号“％formsequence”在第37行需要明确的软件包名称 [英] Global symbol "%formsequence" requires explicit package name at line 37

问题描述

我正在尝试执行Perl CGI脚本，但是出现错误：

I am trying to execute a Perl CGI script, but I am getting an error:

Global symbol "%formsequence" requires explicit package name at line 37.

我做了一些研究，发现 use strict 迫使我在使用变量或存储任何数据之前先声明变量，但是在程序中我已经声明了变量，这就是为什么我不理解错误的原因。这是我的脚本：

I did some research and found that use strict forces me to declare the variables before I use them or store any data, but in my program I have declared them and that is why I don't understand the error. Here is my script:

   #!/usr/bin/perl -w

use strict;

my %errors;
my %form;
my @formsequence;

my %fields = (

        "lname" => "Last Name",
        "phone" => "Phone",
        "fname" => "Fist Name"
        );

my %patterns = (

        "lname" => '[A-Z][a-z]{2,50}',
        "phone" => '\d{3}-\d{3}-\d{4}',
        "fname" => '[A-Z][A-Za-z]{2,60}'
        );

@formsequence = ("lname", "phone", "phone");

print "content-type/html\n\n";

if ($ENV{REQUEST_METHOD} eq "POST") {

        &readformdata;
        if (&checkrequiredfields) {

                print "Form Data validated successfully!";
        }
        else {
                foreach (keys (%fields)) {

                        if ($fields{$_} != $formsequence{$_}) { <-- line 37
                                $errors{$_}="Not in correct sequence\n";
                        }

                }

        }

推荐答案

我怀疑您可能是从PHP开发人员的角度看待数组的概念。在Perl中，哈希和数组是单独的数据结构。

I suspect you may be viewing the concept of an 'array' from the perspective of a PHP developer. In Perl a hash and an array are separate data structures.

数组使用 @ 前缀声明，您可以引用

Arrays are declared using the @ prefix and you refer to elements using square brackets around an integer index:

my @names = ('Tom', 'Dick', 'Larry');
say $names[0];        # 'Tom'
say $names[-1];       # 'Larry'
my $count = @names;   # $count now equals 3
foreach my $i (0..$#names) {
    say $names[$i];
}

使用％前缀，您可以在字符串键周围使用花括号来引用元素：

Hashes are declared using the % prefix and you refer to elements using curly braces around a string key:

my %rgb = (
    red    => '#ff0000',
    white  => '#ffffff',
    blue   => '#0000ff',
);
say $rgb{'red'};      # '#ff0000'
say $rgb{blue};       # '#0000ff'  quotes optional around bareword keys
foreach my $k (keys %rgb) {
    say $rgb{$k};
}

通常您不会使用键在数组上的功能-实际上，旧版本的Perl甚至不支持它，新版本将返回一定范围的整数（例如： 0..2 ）。

You wouldn't normally use the keys function on an array - in fact older versions of Perl don't even support it, newer versions will return a range of integers (e.g.: 0..2).

在散列上调用键时，键没有固有顺序，并且顺序可能会更改

When you call keys on a hash the keys have no inherent order, and the order may change.

其他值得注意的事情：

使用& 调用函数是真正的旧样式（即90年代初），这些天我们将使用 readformdata（）而不是& readformdata 。

Using & to call a function is really old style (i.e. early 90s), these days we'd use readformdata() instead of &readformdata.

！= 运算符是 numeric 比较运算符，因此仅在您要比较的值实际上是数字时才使用它。如果要检查两个字符串是否相等，则使用 ne 代替（例如： if（$ thing1 ne $ thing2）{... } ）。

The != operator is a numeric comparison operator so only use it when the values you're comparing are actually numbers. If you want to check two strings are 'not equal' then use ne instead (e.g.: if($thing1 ne $thing2) { ... }).

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