CGI::FormBuilder::Field(3p)

NAME
CGI::FormBuilder::Field - Base class for FormBuilder fields

SYNOPSIS
    use CGI::FormBuilder::Field;

    # delegated straight from FormBuilder
    my $f = CGI::FormBuilder::Field->new($form, name => 'whatever');

    # attribute functions
    my $n = $f->name;         # name of field
    my $n = "$f";             # stringify to $f->name

    my $t = $f->type;         # auto-type
    my @v = $f->value;        # auto-stickiness
    my @o = $f->options;      # options, aligned and sorted

    my $l = $f->label;        # auto-label
    my $h = $f->tag;          # field XHTML tag (name/type/value)
    my $s = $f->script;       # per-field JS validation script

    my $m = $f->message;      # error message if invalid
    my $m = $f->jsmessage;    # JavaScript error message

    my $r = $f->required;     # required?
    my $k = $f->validate;     # run validation check

    my $v = $f->tag_value;    # value in tag (stickiness handling)
    my $v = $f->cgi_value;    # CGI value if any
    my $v = $f->def_value;    # manually-specified value

    $f->field(opt => 'val');  # FormBuilder field() call

DESCRIPTION
This module is internally used by FormBuilder to create and maintain field information. Usually, you will not want to directly access this set of data structures. However, one big exception is if you are going to micro-control form rendering. In this case, you will need to access the field objects directly.

To do so, you will want to loop through the fields in order:

    for my $field ($form->field) {

        # $field holds an object stringified to a field name
        if ($field =~ /_date$/) {
            $field->sticky(0);  # clear CGI value
            print "Enter $field here:", $field->tag;
        } else {
            print $field->label, ': ', $field->tag;
        }
    }

As illustrated, each $field variable actually holds a stringifiable object. This means if you print them out, you will get the field name, allowing you to check for certain fields. However, since it is an object, you can then run accessor methods directly on that object.

The most useful method is tag(). It generates the HTML input tag for the field, including all option and type handling, and returns a string which you can then print out or manipulate appropriately.

Second to this method is the "script" method, which returns the appropriate JavaScript validation routine for that field. This is useful at the top of your form rendering, when you are printing out the leading "<head>" section of your HTML document. It is called by the $form method of the same name.

The following methods are provided for each $field object.

METHODS

  new($form, %args)
This creates a new $field object. The first argument must be a reference to the top-level $form object, for callbacks. The remaining arguments should be hash, of which one "key/value" pair must specify the "name" of the field. Normally you should not touch this method. Ever.

  field(%args)
This is a delegated field call. This is how FormBuilder tweaks its fields. Once you have a $field object, you call this method the exact same way that you would call the main field() method, minus the field name. Again you should use the top-level call instead.

  inflate($subref)
This sets the inflate attribute: subroutine reference used to inflate values returned by value() into objects or whatever you want. If no parameter, returns the inflate subroutine reference that is set. For example:

 use DateTime::Format::Strptime;
 my $date_format = DateTime::Format::Strptime->new(
    pattern   => '%D',    # for MM/DD/YYYY american dates
    locale    => 'en_US',
    time_zone => 'America/Los_Angeles',
 );
 $field->inflate( sub { return $date_format->format_datetime(shift) } );

  invalid
This returns the opposite value that validate() would return, with some extra magic that keeps state for form rendering purposes.

  jsfunc()
Returns the appropriate JavaScript validation code (see above).

  label($str)
This sets and returns the field's label. If unset, it will be generated from the name of the field.

  tag($type)
Returns an XHTML form input tag (see above). By default it renders the tag based on the type set from the top-level field method:

    $form->field(name => 'poetry', type => 'textarea');

However, if you are doing custom rendering you can override this temporarily by passing in the type explicitly. This is usually not useful unless you have a custom rendering module that forcibly overrides types for certain fields.

  type($type)
This sets and returns the field's type. If unset, it will automatically generate the appropriate field type, depending on the number of options and whether multiple values are allowed:

    Field options?
        No = text (done)
        Yes:
            Less than 'selectnum' setting?
                No = select (done)
                Yes:
                    Is the 'multiple' option set?
                    Yes = checkbox (done)
                    No:
                        Have just one single option?
                            Yes = checkbox (done)
                            No = radio (done)

For an example, view the inside guts of this module.

  validate($pattern)
This returns 1 if the field passes the validation pattern(s) and "required" status previously set via required() and (possibly) the top-level new() call in FormBuilder. Usually running per-field validate() calls is not what you want. Instead, you want to run the one on $form, which in turn calls each individual field's and saves some temp state.

  value($val)
This sets the field's value. It also returns the appropriate value: CGI if set, otherwise the manual default value. Same as using field() to retrieve values.

  tag_value()
This obeys the "sticky" flag to give a different interpretation of CGI values. Use this to get the value if generating your own tag. Otherwise, ignore it completely.

  cgi_value()
This always returns the CGI value, regardless of "sticky".

  def_value()
This always returns the default value, regardless of "sticky".

  tag_name()
This returns the tag name of the current item. This was added so you could subclass, say, "CGI::FormBuilder::Field::select" and change the HTML tag to "<b:select>" instead. This is an experimental feature and subject to change wildly (suggestions welcome).

  accessors
In addition to the above methods, accessors are provided for directly manipulating values as if from a field() call:

    Accessor                Same as...
    ----------------------- -----------------------------------
    $f->force(0|1)          $form->field(force => 0|1)
    $f->options(\@opt)      $form->field(options => \@opt)
    $f->multiple(0|1)       $form->field(multiple => 0|1)
    $f->message($mesg)      $form->field(message => $mesg)
    $f->jsmessage($mesg)    $form->field(jsmessage => $mesg)
    $f->jsclick($code)      $form->field(jsclick => $code)
    $f->sticky(0|1)         $form->field(sticky => 0|1);
    $f->force(0|1)          $form->field(force => 0|1);
    $f->growable(0|1)       $form->field(growable => 0|1);
    $f->other(0|1)          $form->field(other => 0|1);

SEE ALSO
CGI::FormBuilder

REVISION
$Id: Field.pm 100 2007-03-02 18:13:13Z nwiger $

AUTHOR
Copyright (c) 2000-2006 Nate Wiger <nate@wiger.org>. All Rights Reserved.

This module is free software; you may copy this under the terms of the GNU General Public License, or the Artistic License, copies of which should have accompanied your Perl kit.