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Open Source Web Development with LAMP: Using Linux, Apache, MySQL, Perl, and PHP
By
James Lee, Brent Ware
Topics covered include:
A comprehensive survey of Open Source technologiesStatic and dynamic data and embedded HTML on the WebLinux and Unix distributions, installations, and commandsApache Web Server, Perl, and MySQLWeb site META language (WML)Common gateway interface (CGI) and mod_perlServer Side Includes (SSI), Embperl, and MasonPHP syntax and functionsIn addition to the discussions in the book, a companion Web site-www.opensourcewebbook.com-contains supplemental information, including tools, source code, helpful links to additional resources, and errata as needed.Complete in coverage and practical in presentation, Open Source Web Development with LAMP spotlights the tools and technologies today''''s developers need to create workable, dynamic, and secure Web sites using Open Source technologies.
10.7 Other Embperl Variables$row and $col
Embperl can generate one- or two-dimensional tables dynamically with the use of $row and/or $col. If either $row or $col (or $cnt) is used within a <table>, Embperl repeats the text between <table> and </table> as long as the expression that includes $row/$col does not evaluate to undef.For instance, if a program has this code:
[- @nums = (1..5); -]
<table>
<tr><td>[+ $nums[$row] +]</td></tr>
</table>
this means start the table and then use $row to loop through @nums, one element at a time. And because it is $row, each element is treated as a row, so it repeats <tr><td> ... </td></tr>. Therefore, this is the result of this code:
<table>
<tr><td>1</td></tr>
<tr><td>2</td></tr>
<tr><td>3</td></tr>
<tr><td>4</td></tr>
<tr><td>5</td></tr>
</table>
Changing the code to this:
[- @nums = (1..5); -]
<table>
<tr><td>[+ $nums[$col] +]</td></tr>
</table>
loops through @nums, and because we use $col, each element is treated as a column, so it repeats <td> ... </td>. Therefore, this is the result of this code:
<table>
<tr><td>1</td><td>2</td><td>3</td><td>4</td><td>5</td></tr>
</table>
Cool HTML table magic!As an example, we display the environment variables in a table. First, we show how the table might be built without the magic and then how more magic makes life better. This code can be found in /var/www/html/embperl/rowcoll:
<html>
<head>
<title>Using $row and $col</title>
</head>
<body bgcolor="#ffffff">
<h1>Using a <tt>foreach</tt></h1>
<table border="1">
[# loop through the sorted keys of %ENV, #]
[# printing the keys and their values #]
[$ foreach $key (sort keys %ENV) $]
<tr><th> [+ $key +] </th><td> [+ $ENV{$key} +] </td></tr>
[$ endforeach $]
</table>
<h1>Using the Magical <tt>$row</tt> and <tt>$col</tt></h1>
[# grab the sorted keys of %ENV, put them in @k #]
[# then, define one row in the table, and $row will #]
[# magically take on the values of the indices of @k #]
[- @k = sort keys %ENV -]
<table border="1">
<tr><th> [+ $k[$row] +] </th><td> [+ $ENV{$k[$row]} +] </td></tr>
</table>
</body>
</html>
Try this program by going to one of these URLs: http://localhost/embperl/rowcoll or www.opensourcewebbook.com/embperl/rowcoll. You should see something that resembles Figure 10.6.
Figure 10.6. Using $row and $col
