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19.5 Less Typing

That's still a lot of typing. It turns out that CGI.pm includes a whole slew of convenience functions for simplifying this. Each of these routines returns a string for you to output. For example, header() returns a string containing the Content-type line with a following blank line, start_html( string ) returns string as an HTML title, h1( string ) returns string as a first-level HTML heading, and p( string ) returns string as a new HTML paragraph.

We could list all these functions in the import list given with use , but that will eventually grow too unwieldy. However, CGI.pm, like many modules, provides you with import tags  - labels that stand for groups of functions to import. You simply place the desired tags (each of which begins with a colon) at the beginning of your import list. The tags available with CGI.pm include these:


Import all argument-handling methods, such as param() .


Import all fill-out form generating methods, such as textfield() .


Import all methods that generate HTML 2.0 standard elements.


Import all methods that generate HTML 3.0 elements (such as <table> , <super>, and <sub> ).


Import all methods that generate Netscape-specific HTML extensions.


Import all HTML-generating shortcuts (that is, "html2" + "html3" + "netscape").


Import "standard" features: "html2", "form", and "cgi".


Import all the available methods. For the full list, see the CGI.pm module, where the variable %TAGS is defined.

We'll just use :standard . (For more about importing functions and variables from modules, see the Exporter module in Chapter 7 of Programming Perl , or the Exporter (3) manpage.)

Here's our program using all the shortcuts CGI.pm provides:

#!/usr/bin/perl -w
# cgi-bin/ice_cream: program to answer ice cream
# favorite flavor form (version 2)
use CGI qw(:standard);
print header(), start_html("Hello World"), h1("Greetings, Terrans!");
my $favorite = param("flavor");
print p("Your favorite flavor is $favorite.");
print end_html();

See how much easier that is? You don't have to worry about form decoding, headers, or HTML if you don't want to.