NAME
    HTML::FormFu - HTML Form Creation, Rendering and Validation Framework

SYNOPSIS
    Note: These examples make use of HTML::FormFu::Model::DBIC. As of
    "HTML::FormFu" v02.005, the HTML::FormFu::Model::DBIC module is not
    bundled with "HTML::FormFu" and is available in a stand-alone
    distribution.

        use HTML::FormFu;

        my $form = HTML::FormFu->new;

        $form->load_config_file('form.yml');

        $form->process( $cgi_query );

        if ( $form->submitted_and_valid ) {
            # do something with $form->params
        }
        else {
            # display the form
            $template->param( form => $form );
        }

    If you're using Catalyst, a more suitable example might be:

        package MyApp::Controller::User;
        use strict;
        use base 'Catalyst::Controller::HTML::FormFu';

        sub user : Chained CaptureArgs(1) {
            my ( $self, $c, $id ) = @_;

            my $rs = $c->model('Schema')->resultset('User');

            $c->stash->{user} = $rs->find( $id );

            return;
        }

        sub edit : Chained('user') Args(0) FormConfig {
            my ( $self, $c ) = @_;

            my $form = $c->stash->{form};
            my $user = $c->stash->{user};

            if ( $form->submitted_and_valid ) {

                $form->model->update( $user );

                $c->res->redirect( $c->uri_for( "/user/$id" ) );
                return;
            }

            $form->model->default_values( $user )
                if ! $form->submitted;

        }

    Note: Because "process" is automatically called for you by the Catalyst
    controller; if you make any modifications to the form within your action
    method, such as adding or changing elements, adding constraints, etc;
    you must call "process" again yourself before using
    "submitted_and_valid", any of the methods listed under "SUBMITTED FORM
    VALUES AND ERRORS" or "MODIFYING A SUBMITTED FORM", or rendering the
    form.

    Here's an example of a config file to create a basic login form (all
    examples here are YAML, but you can use any format supported by
    Config::Any), you can also create forms directly in your perl code,
    rather than using an external config file.

        ---
        action: /login
        indicator: submit
        auto_fieldset: 1

        elements:
          - type: Text
            name: user
            constraints:
              - Required

          - type: Password
            name: pass
            constraints:
              - Required

          - type: Submit
            name: submit

        constraints:
          - SingleValue

DESCRIPTION
    HTML::FormFu is a HTML form framework which aims to be as easy as
    possible to use for basic web forms, but with the power and flexibility
    to do anything else you might want to do (as long as it involves forms).

    You can configure almost any part of formfu's behaviour and output. By
    default formfu renders "XHTML 1.0 Strict" compliant markup, with as
    little extra markup as possible, but with sufficient CSS class names to
    allow for a wide-range of output styles to be generated by changing only
    the CSS.

    All methods listed below (except "new") can either be called as a normal
    method on your $form object, or as an option in your config file.
    Examples will mainly be shown in YAML config syntax.

    This documentation follows the convention that method arguments
    surrounded by square brackets "[]" are *optional*, and all other
    arguments are required.

BUILDING A FORM
  new
    Arguments: [\%options]

    Return Value: $form

    Create a new HTML::FormFu object.

    Any method which can be called on the HTML::FormFu object may instead be
    passed as an argument to "new".

        my $form = HTML::FormFu->new({
            action        => '/search',
            method        => 'GET',
            auto_fieldset => 1,
        });

  load_config_file
    Arguments: $filename

    Arguments: \@filenames

    Return Value: $form

    Accepts a filename or list of file names, whose filetypes should be of
    any format recognized by Config::Any.

    The content of each config file is passed to "populate", and so are
    added to the form.

    "load_config_file" may be called in a config file itself, so as to allow
    common settings to be kept in a single config file which may be loaded
    by any form.

        ---
        load_config_file:
          - file1
          - file2

    YAML multiple documents within a single file. The document start marker
    is a line containing 3 dashes. Multiple documents will be applied in
    order, just as if multiple filenames had been given.

    In the following example, multiple documents are taken advantage of to
    load another config file after the elements are added. (If this were a
    single document, the "load_config_file" would be called before
    "elements", regardless of its position in the file).

        ---
        elements:
          - name: one
          - name: two

        ---
        load_config_file: ext.yml

    Relative paths are resolved from the "config_file_path" directory if it
    is set, otherwise from the current working directory.

    See "BEST PRACTICES" for advice on organising config files.

  config_callback
    Arguments: \%options

    If defined, the arguments are used to create a Data::Visitor::Callback
    object during "load_config_file" which may be used to pre-process the
    config before it is sent to "populate".

    For example, the code below adds a callback to a form that will
    dynamically alter any config value ending in ".yml" to end in ".yaml"
    when you call "load_config_file":

        $form->config_callback({
          plain_value => sub {
            my( $visitor, $data ) = @_;
            s/\.yml/.yaml/;
          }
        });

    Default Value: not defined

    This method is a special 'inherited accessor', which means it can be set
    on the form, a block element or a single element. When the value is
    read, if no value is defined it automatically traverses the element's
    hierarchy of parents, through any block elements and up to the form,
    searching for a defined value.

  populate
    Arguments: \%options

    Return Value: $form

    Each option key/value passed may be any HTML::FormFu method-name and
    arguments.

    Provides a simple way to set multiple values, or add multiple elements
    to a form with a single method-call.

    Attempts to call the method-names in a semi-intelligent order (see the
    source of populate() in "HTML::FormFu::ObjectUtil" for details).

  default_values
    Arguments: \%defaults

    Return Value: $form

    Set multiple field's default values from a single hash-ref.

    The hash-ref's keys correspond to a form field's name, and the value is
    passed to the field's default method.

    This should be called after all fields have been added to the form, and
    before "process" is called (otherwise, call "process" again before
    rendering the form).

  config_file_path
    Arguments: $directory_name

    "config_file_path" defines where configuration files will be searched
    for, if an absolute path is not given to "load_config_file".

    Default Value: not defined

    This method is a special 'inherited accessor', which means it can be set
    on the form, a block element or a single element. When the value is
    read, if no value is defined it automatically traverses the element's
    hierarchy of parents, through any block elements and up to the form,
    searching for a defined value.

  indicator
    Arguments: $field_name

    Arguments: \&coderef

    If "indicator" is set to a fieldname, "submitted" will return true if a
    value for that fieldname was submitted.

    If "indicator" is set to a code-ref, it will be called as a subroutine
    with the two arguments $form and $query, and its return value will be
    used as the return value for "submitted".

    If "indicator" is not set, "submitted" will return true if a value for
    any known fieldname was submitted.

  auto_fieldset
    Arguments: 1

    Arguments: \%options

    Return Value: $fieldset

    This setting is suitable for most basic forms, and means you can
    generally ignore adding fieldsets yourself.

    Calling "$form->auto_fieldset(1)" immediately adds a fieldset element to
    the form. Thereafter, "$form->elements()" will add all elements (except
    fieldsets) to that fieldset, rather than directly to the form.

    To be specific, the elements are added to the *last* fieldset on the
    form, so if you add another fieldset, any further elements will be added
    to that fieldset.

    Also, you may pass a hashref to auto_fieldset(), and this will be used
    to set defaults for the first fieldset created.

    A few examples and their output, to demonstrate:

    2 elements with no fieldset.

        ---
        elements:
          - type: Text
            name: foo
          - type: Text
            name: bar

        <form action="" method="post">
          <div class="text">
            <input name="foo" type="text" />
          </div>
          <div class="text">
            <input name="bar" type="text" />
          </div>
        </form>

    2 elements with an "auto_fieldset".

        ---
        auto_fieldset: 1
        elements:
          - type: Text
            name: foo
          - type: Text
            name: bar

        <form action="" method="post">
          <fieldset>
            <div class="text">
              <input name="foo" type="text" />
            </div>
            <div class="text">
              <input name="bar" type="text" />
            </div>
          </fieldset>
        </form>

    The 3rd element is within a new fieldset

        ---
        auto_fieldset: { id: fs }
        elements:
          - type: Text
            name: foo
          - type: Text
            name: bar
          - type: Fieldset
          - type: Text
            name: baz

        <form action="" method="post">
          <fieldset id="fs">
            <div class="text">
              <input name="foo" type="text" />
            </div>
            <div class="text">
              <input name="bar" type="text" />
            </div>
          </fieldset>
          <fieldset>
            <div class="text">
              <input name="baz" type="text" />
            </div>
          </fieldset>
        </form>

    Because of this behaviour, if you want nested fieldsets you will have to
    add each nested fieldset directly to its intended parent.

        my $parent = $form->get_element({ type => 'Fieldset' });

        $parent->element('fieldset');

  form_error_message
    Arguments: $string

    Normally, input errors cause an error message to be displayed alongside
    the appropriate form field. If you'd also like a general error message
    to be displayed at the top of the form, you can set the message with
    "form_error_message".

    To change the markup used to display the message, edit the
    "form_error_message" template file.

  form_error_message_xml
    Arguments: $string

    If you don't want your error message to be XML-escaped, use the
    "form_error_message_xml" method instead.

  form_error_message_loc
    Arguments: $localization_key

    For ease of use, if you'd like to use the provided localized error
    message, set "form_error_message_loc" to the value "form_error_message".

    You can, of course, set "form_error_message_loc" to any key in your I18N
    file.

  force_error_message
    If true, forces the "form_error_message" to be displayed even if there
    are no field errors.

  default_args
    Arguments: \%defaults

    Set defaults which will be added to every element, constraint, etc. of
    the listed type (or derived from the listed type) which is added to the
    form.

    For example, to make every "Text" element automatically have a size of
    10, and make every "Strftime" deflator automatically get its strftime
    set to "%d/%m/%Y":

        default_args:
            elements:
                Text:
                    size: 10
            deflators:
                Strftime:
                    strftime: '%d/%m/%Y'

    To take it even further, you can even make all DateTime elements
    automatically get an appropriate Strftime deflator and a DateTime
    inflator:

        default_args:
            elements:
                DateTime:
                    deflators:
                        type: Strftime
                        strftime: '%d-%m-%Y'
                    inflators:
                        type: DateTime
                        parser:
                            strptime: '%d-%m-%Y'

    To have defaults only be applied to the specific named type, rather than
    searching through derived types, append the type-name with "+".

    For example, to have the following attributes only be applied to a
    "Block" element, rather than any element that inherits from "Block",
    such as "Multi":

        default_args:
            elements:
                +Block:
                    attributes:
                        class: block

    Note: Unlike the proper methods which have aliases, for example
    "elements" which is an alias for "element" - the keys given to
    "default_args" must be of the plural form, e.g.:

        default_args:
            elements:          {}
            deflators:         {}
            filters:           {}
            constraints:       {}
            inflators:         {}
            validators:        {}
            transformers:      {}
            output_processors: {}

  javascript
    Arguments: [$javascript]

    If set, the contents will be rendered within a "script" tag, inside the
    top of the form.

  stash
    Arguments: [\%private_stash]

    Return Value: \%stash

    Provides a hash-ref in which you can store any data you might want to
    associate with the form.

        ---
        stash:
          foo: value
          bar: value

  elements
  element
    Arguments: $type

    Arguments: \%options

    Return Value: $element

    Arguments: \@arrayref_of_types_or_options

    Return Value: @elements

    Adds a new element to the form. See "CORE FORM FIELDS" in
    HTML::FormFu::Element and "OTHER CORE ELEMENTS" in HTML::FormFu::Element
    for a list of core elements.

    If you want to load an element from a namespace other than
    "HTML::FormFu::Element::", you can use a fully qualified package-name by
    prefixing it with "+".

        ---
        elements:
          - type: +MyApp::CustomElement
            name: foo

    If a "type" is not provided in the "\%options", the default "Text" will
    be used.

    "element" is an alias for "elements".

  deflators
  deflator
    Arguments: $type

    Arguments: \%options

    Return Value: $deflator

    Arguments: \@arrayref_of_types_or_options

    Return Value: @deflators

    A deflator may be associated with any form field, and allows you to
    provide $field->default with a value which may be an object.

    If an object doesn't stringify to a suitable value for display, the
    deflator can ensure that the form field receives a suitable string value
    instead.

    See "CORE DEFLATORS" in HTML::FormFu::Deflator for a list of core
    deflators.

    If a "name" attribute isn't provided, a new deflator is created for and
    added to every field on the form.

    If you want to load a deflator in a namespace other than
    "HTML::FormFu::Deflator::", you can use a fully qualified package-name
    by prefixing it with "+".

    "deflator" is an alias for "deflators".

  insert_before
    Arguments: $new_element, $existing_element

    Return Value: $new_element

    The 1st argument must be the element you want added, the 2nd argument
    must be the existing element that the new element should be placed
    before.

        my $new = $form->element(\%specs);

        my $position = $form->get_element({ type => $type, name => $name });

        $form->insert_before( $new, $position );

    In the first line of the above example, the $new element is initially
    added to the end of the form. However, the "insert_before" method
    reparents the $new element, so it will no longer be on the end of the
    form. Because of this, if you try to copy an element from one form to
    another, it will 'steal' the element, instead of copying it. In this
    case, you must use "clone":

        my $new = $form1->get_element({ type => $type1, name => $name1 })
                        ->clone;

        my $position = $form2->get_element({ type => $type2, name => $name2 });

        $form2->insert_before( $new, $position );

  insert_after
    Arguments: $new_element, $existing_element

    Return Value: $new_element

    The 1st argument must be the element you want added, the 2nd argument
    must be the existing element that the new element should be placed
    after.

        my $new = $form->element(\%specs);

        my $position = $form->get_element({ type => $type, name => $name });

        $form->insert_after( $new, $position );

    In the first line of the above example, the $new element is initially
    added to the end of the form. However, the "insert_after" method
    reparents the $new element, so it will no longer be on the end of the
    form. Because of this, if you try to copy an element from one form to
    another, it will 'steal' the element, instead of copying it. In this
    case, you must use "clone":

        my $new = $form1->get_element({ type => $type1, name => $name1 })
                        ->clone;

        my $position = $form2->get_element({ type => $type2, name => $name2 });

        $form2->insert_after( $new, $position );

  remove_element
    Arguments: $element

    Return Value: $element

    Removes the $element from the form or block's array of children.

        $form->remove_element( $element );

    The orphaned element cannot be usefully used for anything until it is
    re-attached to a form or block with "insert_before" or "insert_after".

FORM LOGIC AND VALIDATION
    HTML::FormFu provides several stages for what is traditionally described
    as *validation*. These are:

    HTML::FormFu::Filter
    HTML::FormFu::Constraint
    HTML::FormFu::Inflator
    HTML::FormFu::Validator
    HTML::FormFu::Transformer

    The first stage, the filters, allow for cleanup of user-input, such as
    encoding, or removing leading/trailing whitespace, or removing non-digit
    characters from a creditcard number.

    All of the following stages allow for more complex processing, and each
    of them have a mechanism to allow exceptions to be thrown, to represent
    input errors. In each stage, all form fields must be processed without
    error for the next stage to proceed. If there were any errors, the form
    should be re-displayed to the user, to allow them to input correct
    values.

    Constraints are intended for low-level validation of values, such as "is
    this an integer?", "is this value within bounds?" or "is this a valid
    email address?".

    Inflators are intended to allow a value to be turned into an appropriate
    object. The resulting object will be passed to subsequent Validators and
    Transformers, and will also be returned by "params" and "param".

    Validators are intended for higher-level validation, such as
    business-logic and database constraints such as "is this username
    unique?". Validators are only run if all Constraints and Inflators have
    run without errors. It is expected that most Validators will be
    application-specific, and so each will be implemented as a separate
    class written by the HTML::FormFu user.

  filters
  filter
    Arguments: $type

    Arguments: \%options

    Return Value: $filter

    Arguments: \@arrayref_of_types_or_options

    Return Value: @filters

    If you provide a "name" or "names" value, the filter will be added to
    just that named field. If you do not provide a "name" or "names" value,
    the filter will be added to all fields already attached to the form.

    See "CORE FILTERS" in HTML::FormFu::Filter for a list of core filters.

    If you want to load a filter in a namespace other than
    "HTML::FormFu::Filter::", you can use a fully qualified package-name by
    prefixing it with "+".

    "filter" is an alias for "filters".

  constraints
  constraint
    Arguments: $type

    Arguments: \%options

    Return Value: $constraint

    Arguments: \@arrayref_of_types_or_options

    Return Value: @constraints

    See "CORE CONSTRAINTS" in HTML::FormFu::Constraint for a list of core
    constraints.

    If a "name" attribute isn't provided, a new constraint is created for
    and added to every field on the form.

    If you want to load a constraint in a namespace other than
    "HTML::FormFu::Constraint::", you can use a fully qualified package-name
    by prefixing it with "+".

    "constraint" is an alias for "constraints".

  inflators
  inflator
    Arguments: $type

    Arguments: \%options

    Return Value: $inflator

    Arguments: \@arrayref_of_types_or_options

    Return Value: @inflators

    See "CORE INFLATORS" in HTML::FormFu::Inflator for a list of core
    inflators.

    If a "name" attribute isn't provided, a new inflator is created for and
    added to every field on the form.

    If you want to load an inflator in a namespace other than
    "HTML::FormFu::Inflator::", you can use a fully qualified package-name
    by prefixing it with "+".

    "inflator" is an alias for "inflators".

  validators
  validator
    Arguments: $type

    Arguments: \%options

    Return Value: $validator

    Arguments: \@arrayref_of_types_or_options

    Return Value: @validators

    See "CORE VALIDATORS" in HTML::FormFu::Validator for a list of core
    validators.

    If a "name" attribute isn't provided, a new validator is created for and
    added to every field on the form.

    If you want to load a validator in a namespace other than
    "HTML::FormFu::Validator::", you can use a fully qualified package-name
    by prefixing it with "+".

    "validator" is an alias for "validators".

  transformers
  transformer
    Arguments: $type

    Arguments: \%options

    Return Value: $transformer

    Arguments: \@arrayref_of_types_or_options

    Return Value: @transformers

    See "CORE TRANSFORMERS" in HTML::FormFu::Transformer for a list of core
    transformers.

    If a "name" attribute isn't provided, a new transformer is created for
    and added to every field on the form.

    If you want to load a transformer in a namespace other than
    "HTML::FormFu::Transformer::", you can use a fully qualified
    package-name by prefixing it with "+".

    "transformer" is an alias for "transformers".

CHANGING DEFAULT BEHAVIOUR
  render_processed_value
    The default behaviour when re-displaying a form after a submission, is
    that the field contains the original unchanged user-submitted value.

    If "render_processed_value" is true, the field value will be the final
    result after all Filters, Inflators and Transformers have been run.
    Deflators will also be run on the value.

    If you set this on a field with an Inflator, but without an equivalent
    Deflator, you should ensure that the Inflators stringify back to a
    usable value, so as not to confuse / annoy the user.

    Default Value: false

    This method is a special 'inherited accessor', which means it can be set
    on the form, a block element or a single element. When the value is
    read, if no value is defined it automatically traverses the element's
    hierarchy of parents, through any block elements and up to the form,
    searching for a defined value.

  force_errors
    Force a constraint to fail, regardless of user input.

    If this is called at runtime, after the form has already been processed,
    you must called "process" in HTML::FormFu again before redisplaying the
    form to the user.

    Default Value: false

    This method is a special 'inherited accessor', which means it can be set
    on the form, a block element, an element or a single constraint. When
    the value is read, if no value is defined it automatically traverses the
    element's hierarchy of parents, through any block elements and up to the
    form, searching for a defined value.

  params_ignore_underscore
    If true, causes "params", "param" and "valid" to ignore any fields whose
    name starts with an underscore "_".

    The field is still processed as normal, and errors will cause
    "submitted_and_valid" to return false.

    Default Value: false

FORM ATTRIBUTES
    All attributes are added to the rendered form's start tag.

  attributes
  attrs
    Arguments: [%attributes]

    Arguments: [\%attributes]

    Return Value: $form

    Accepts either a list of key/value pairs, or a hash-ref.

        ---
        attributes:
          id: form
          class: fancy_form

    As a special case, if no arguments are passed, the attributes hash-ref
    is returned. This allows the following idioms.

        # set a value
        $form->attributes->{id} = 'form';

        # delete all attributes
        %{ $form->attributes } = ();

    "attrs" is an alias for "attributes".

  attributes_xml
  attrs_xml
    Provides the same functionality as "attributes", but values won't be
    XML-escaped.

    "attrs_xml" is an alias for "attributes_xml".

  add_attributes
  add_attrs
    Arguments: [%attributes]

    Arguments: [\%attributes]

    Return Value: $form

    Accepts either a list of key/value pairs, or a hash-ref.

        $form->add_attributes( $key => $value );
        $form->add_attributes( { $key => $value } );

    All values are appended to existing values, with a preceding space
    character. This is primarily to allow the easy addition of new names to
    the class attribute.

        $form->attributes({ class => 'foo' });

        $form->add_attributes({ class => 'bar' });

        # class is now 'foo bar'

    "add_attrs" is an alias for "add_attributes".

  add_attributes_xml
  add_attrs_xml
    Provides the same functionality as "add_attributes", but values won't be
    XML-escaped.

    "add_attrs_xml" is an alias for "add_attributes_xml".

  del_attributes
  del_attrs
    Arguments: [%attributes]

    Arguments: [\%attributes]

    Return Value: $form

    Accepts either a list of key/value pairs, or a hash-ref.

        $form->del_attributes( $key => $value );
        $form->del_attributes( { $key => $value } );

    All values are removed from the attribute value.

        $form->attributes({ class => 'foo bar' });

        $form->del_attributes({ class => 'bar' });

        # class is now 'foo'

    "del_attrs" is an alias for "del_attributes".

  del_attributes_xml
  del_attrs_xml
    Provides the same functionality as "del_attributes", but values won't be
    XML-escaped.

    "del_attrs_xml" is an alias for "del_attributes_xml".

    The following methods are shortcuts for accessing "attributes" keys.

  id
    Arguments: [$id]

    Return Value: $id

    Get or set the form's DOM id.

    Default Value: none

  action
    Arguments: [$uri]

    Return Value: $uri

    Get or set the action associated with the form. The default is no
    action, which causes most browsers to submit to the current URI.

    Default Value: ""

  enctype
    Arguments: [$enctype]

    Return Value: $enctype

    Get or set the encoding type of the form. Valid values are
    "application/x-www-form-urlencoded" and "multipart/form-data".

    If the form contains a File element, the enctype is automatically set to
    "multipart/form-data".

  method
    Arguments: [$method]

    Return Value: $method

    Get or set the method used to submit the form. Can be set to either
    "post" or "get".

    Default Value: "post"

CSS CLASSES
  auto_id
    Arguments: [$string]

    If set, then each form field will be given an auto-generated id
    attribute, if it doesn't have one already.

    The following character substitution will be performed: %f will be
    replaced by $form->id, %n will be replaced by $field->name, %r will be
    replaced by $block->repeatable_count.

    Default Value: not defined

    This method is a special 'inherited accessor', which means it can be set
    on the form, a block element or a single element. When the value is
    read, if no value is defined it automatically traverses the element's
    hierarchy of parents, through any block elements and up to the form,
    searching for a defined value.

  auto_label
    Arguments: [$string]

    If set, then each form field will be given an auto-generated label, if
    it doesn't have one already.

    The following character substitution will be performed: %f will be
    replaced by $form->id, %n will be replaced by $field->name.

    The generated string will be passed to "localize" to create the label.

    Default Value: not defined

    This method is a special 'inherited accessor', which means it can be set
    on the form, a block element or a single element. When the value is
    read, if no value is defined it automatically traverses the element's
    hierarchy of parents, through any block elements and up to the form,
    searching for a defined value.

  auto_error_class
    Arguments: [$string]

    If set, then each form error will be given an auto-generated class-name.

    The following character substitution will be performed: %f will be
    replaced by $form->id, %n will be replaced by $field->name, %t will be
    replaced by lc( $field->type ), %s will be replaced by $error->stage.

    Default Value: 'error_%s_%t'

    This method is a special 'inherited accessor', which means it can be set
    on the form, a block element or a single element. When the value is
    read, if no value is defined it automatically traverses the element's
    hierarchy of parents, through any block elements and up to the form,
    searching for a defined value.

  auto_error_message
    Arguments: [$string]

    If set, then each form field will be given an auto-generated message, if
    it doesn't have one already.

    The following character substitution will be performed: %f will be
    replaced by $form->id, %n will be replaced by $field->name, %t will be
    replaced by lc( $field->type ), %s will be replaced by $error->stage.

    The generated string will be passed to "localize" to create the message.

    For example, a Required constraint will return the string
    "form_constraint_required". Under the default localization behaviour,
    the appropriate message for "form_constraint_required" will be used from
    the default I18N package.

    Default Value: 'form_%s_%t'

    This method is a special 'inherited accessor', which means it can be set
    on the form, a block element or a single element. When the value is
    read, if no value is defined it automatically traverses the element's
    hierarchy of parents, through any block elements and up to the form,
    searching for a defined value.

  auto_constraint_class
    Arguments: [$string]

    If set, then each form field will be given an auto-generated class-name
    for each associated constraint.

    The following character substitution will be performed: %f will be
    replaced by $form->id, %n will be replaced by $field->name, %t will be
    replaced by lc( $field->type ).

    Default Value: not defined

    This method is a special 'inherited accessor', which means it can be set
    on the form, a block element or a single element. When the value is
    read, if no value is defined it automatically traverses the element's
    hierarchy of parents, through any block elements and up to the form,
    searching for a defined value.

  auto_inflator_class
    Arguments: [$string]

    If set, then each form field will be given an auto-generated class-name
    for each associated inflator.

    The following character substitution will be performed: %f will be
    replaced by $form->id, %n will be replaced by $field->name, %t will be
    replaced by lc( $field->type ).

    Default Value: not defined

    This method is a special 'inherited accessor', which means it can be set
    on the form, a block element or a single element. When the value is
    read, if no value is defined it automatically traverses the element's
    hierarchy of parents, through any block elements and up to the form,
    searching for a defined value.

  auto_validator_class
    Arguments: [$string]

    If set, then each form field will be given an auto-generated class-name
    for each associated validator.

    The following character substitution will be performed: %f will be
    replaced by $form->id, %n will be replaced by $field->name, %t will be
    replaced by lc( $field->type ).

    Default Value: not defined

    This method is a special 'inherited accessor', which means it can be set
    on the form, a block element or a single element. When the value is
    read, if no value is defined it automatically traverses the element's
    hierarchy of parents, through any block elements and up to the form,
    searching for a defined value.

  auto_transformer_class
    Arguments: [$string]

    If set, then each form field will be given an auto-generated class-name
    for each associated validator.

    The following character substitution will be performed: %f will be
    replaced by $form->id, %n will be replaced by $field->name, %t will be
    replaced by lc( $field->type ).

    Default Value: not defined

    This method is a special 'inherited accessor', which means it can be set
    on the form, a block element or a single element. When the value is
    read, if no value is defined it automatically traverses the element's
    hierarchy of parents, through any block elements and up to the form,
    searching for a defined value.

LOCALIZATION
  languages
    Arguments: [\@languages]

    A list of languages which will be passed to the localization object.

    Default Value: ['en']

  localize_class
    Arguments: [$class_name]

    Classname to be used for the default localization object.

    Default Value: 'HTML::FormFu::I18N'

  localize
  loc
    Arguments: [$key, @arguments]

    Compatible with the "maketext" method in Locale::Maketext.

  locale
    Arguments: $locale

    Currently only used by HTML::FormFu::Deflator::FormatNumber and
    HTML::FormFu::Filter::FormatNumber.

    This method is a special 'inherited accessor', which means it can be set
    on the form, a block element or a single element. When the value is
    read, if no value is defined it automatically traverses the element's
    hierarchy of parents, through any block elements and up to the form,
    searching for a defined value.

PROCESSING A FORM
  query
    Arguments: [$query_object]

    Arguments: \%params

    Provide a CGI compatible query object or a hash-ref of submitted
    names/values. Alternatively, the query object can be passed directly to
    the "process" object.

  query_type
    Arguments: [$query_type]

    Set which module is being used to provide the "query".

    The Catalyst::Controller::HTML::FormFu automatically sets this to
    "Catalyst".

    Valid values are "CGI", "Catalyst" and "CGI::Simple".

    Default Value: 'CGI'

  process
    Arguments: [$query_object]

    Arguments: [\%params]

    Process the provided query object or input values. "process" must be
    called before calling any of the methods listed under "SUBMITTED FORM
    VALUES AND ERRORS" and "MODIFYING A SUBMITTED FORM".

    "process" must also be called at least once before printing the form or
    calling "render" or "render_data".

    Note to users of Catalyst::Controller::HTML::FormFu: Because "process"
    is automatically called for you by the Catalyst controller; if you make
    any modifications to the form within your action method, such as adding
    or changing elements, adding constraints, etc; you must call "process"
    again yourself before using "submitted_and_valid", any of the methods
    listed under "SUBMITTED FORM VALUES AND ERRORS" or "MODIFYING A
    SUBMITTED FORM", or rendering the form.

SUBMITTED FORM VALUES AND ERRORS
  submitted
    Returns true if the form has been submitted. See "indicator" for details
    on how this is computed.

  submitted_and_valid
    Shorthand for "$form->submitted && !$form->has_errors"

  params
    Return Value: \%params

    Returns a hash-ref of all valid input for which there were no errors.

  param_value
    Arguments: $field_name

    A more reliable, recommended version of "param". Guaranteed to always
    return a single value, regardless of whether it's called in list context
    or not. If multiple values were submitted, this only returns the first
    value. If the value is invalid or the form was not submitted, it returns
    "undef". This makes it suitable for use in list context, where a single
    value is required.

        $db->update({
            name    => $form->param_value('name'),
            address => $form->param_value('address),
        });

  param_array
    Arguments: $field_name

    Guaranteed to always return an array-ref of values, regardless of
    context and regardless of whether multiple values were submitted or not.
    If the value is invalid or the form was not submitted, it returns an
    empty array-ref.

  param_list
    Arguments: $field_name

    Guaranteed to always return a list of values, regardless of context. If
    the value is invalid or the form was not submitted, it returns an empty
    list.

  param
    Arguments: [$field_name]

    Return Value: $input_value

    Return Value: @valid_names

    No longer recommended for use, as its behaviour is hard to predict. Use
    "param_value", "param_array" or "param_list" instead.

    A (readonly) method similar to that of CGI's.

    If a field name is given, in list-context returns any valid values
    submitted for that field, and in scalar-context returns only the first
    of any valid values submitted for that field.

    If no argument is given, returns a list of all valid input field names
    without errors.

    Passing more than 1 argument is a fatal error.

  valid
    Arguments: [$field_name]

    Return Value: @valid_names

    Return Value: $bool

    If a field name if given, returns "true" if that field had no errors and
    "false" if there were errors.

    If no argument is given, returns a list of all valid input field names
    without errors.

  has_errors
    Arguments: [$field_name]

    Return Value: @names

    Return Value: $bool

    If a field name if given, returns "true" if that field had errors and
    "false" if there were no errors.

    If no argument is given, returns a list of all input field names with
    errors.

  get_errors
    Arguments: [%options]

    Arguments: [\%options]

    Return Value: \@errors

    Returns an array-ref of exception objects from all fields in the form.

    Accepts both "name", "type" and "stage" arguments to narrow the returned
    results.

        $form->get_errors({
            name  => 'foo',
            type  => 'Regex',
            stage => 'constraint'
        });

  get_error
    Arguments: [%options]

    Arguments: [\%options]

    Return Value: $error

    Accepts the same arguments as "get_errors", but only returns the first
    error found.

MODEL / DATABASE INTERACTION
    See HTML::FormFu::Model for further details and available models.

  default_model
    Arguments: $model_name

    Default Value: 'DBIC'

  model
    Arguments: [$model_name]

    Return Value: $model

  model_config
    Arguments: \%config

MODIFYING A SUBMITTED FORM
  add_valid
    Arguments: $name, $value

    Return Value: $value

    The provided value replaces any current value for the named field. This
    value will be returned in subsequent calls to "params" and "param" and
    the named field will be included in calculations for "valid".

  clear_errors
    Deletes all errors from a submitted form.

RENDERING A FORM
  render
    Return Value: $string

    You must call "process" once after building the form, and before calling
    "render".

  start
    Return Value: $string

    Returns the form start tag, and any output of "form_error_message" and
    "javascript".

    Implicitly uses the "tt" "render_method".

  end
    Return Value: $string

    Returns the form end tag.

    Implicitly uses the "tt" "render_method".

  hidden_fields
    Return Value: $string

    Returns all hidden form fields.

PLUGIN SYSTEM
    "HTML::FormFu" provides a plugin-system that allows plugins to be easily
    added to a form or element, to change the default behaviour or output.

    See HTML::FormFu::Plugin for details.

ADVANCED CUSTOMISATION
    By default, formfu renders "XHTML 1.0 Strict" compliant markup, with as
    little extra markup as possible, but with sufficient CSS class names to
    allow for a wide-range of output styles to be generated by changing only
    the CSS.

    If you wish to customise the markup, you'll need to tell HTML::FormFu to
    use an external rendering engine, such as Template Toolkit or
    Template::Alloy. See "render_method" and "tt_module" for details.

    Even if you set HTML::FormFu to use Template::Toolkit to render, the
    forms, HTML::FormFu can still be used in conjunction with whichever
    other templating system you prefer to use for your own page layouts,
    whether it's HTML::Template: "<TMPL_VAR form>", Petal: "<form
    tal:replace="form"></form>" or Template::Magic: "<!-- {form} -->".

  render_method
    Default Value: "string"

    Can be set to "tt" to generate the form with external template files.

    To customise the markup, you'll need a copy of the template files, local
    to your application. See "Installing the TT templates" in
    HTML::FormFu::Manual::Cookbook for further details.

    You can customise the markup for a single element by setting that
    element's "render_method" to "tt", while the rest of the form uses the
    default "string" render-method. Note though, that if you try setting the
    form or a Block's "render_method" to "tt", and then set a child
    element's "render_method" to "string", that setting will be ignored, and
    the child elements will still use the "tt" render-method.

        ---
        elements:
          - name: foo
            render_method: tt
            filename: custom_field

          - name: bar

        # in this example, 'foo' will use a custom template,
        # while bar will use the default 'string' rendering method

    This method is a special 'inherited accessor', which means it can be set
    on the form, a block element or a single element. When the value is
    read, if no value is defined it automatically traverses the element's
    hierarchy of parents, through any block elements and up to the form,
    searching for a defined value.

  filename
    Change the template filename used for the form.

    Default Value: "form"

  tt_args
    Arguments: [\%constructor_arguments]

    Accepts a hash-ref of arguments passed to "render_method", which is
    called internally by "render".

    Within tt_args, the keys "RELATIVE" and "RECURSION" are overridden to
    always be true, as these are a basic requirement for the Template
    engine.

    The system directory containing HTML::FormFu's template files is always
    added to the end of "INCLUDE_PATH", so that the core template files will
    be found. You only need to set this yourself if you have your own copy
    of the template files for customisation purposes.

    This method is a special 'inherited accessor', which means it can be set
    on the form, a block element or a single element. When the value is
    read, if no value is defined it automatically traverses the element's
    hierarchy of parents, through any block elements and up to the form,
    searching for a defined value.

  add_tt_args
    Arguments: [\%constructor_arguments]

    Ensures that the hash-ref argument is merged with any existing hash-ref
    value of "tt_args".

  tt_module
    Default Value: Template

    The module used when "render_method" is set to "tt". Should provide an
    interface compatible with Template.

    This method is a special 'inherited accessor', which means it can be set
    on the form, a block element or a single element. When the value is
    read, if no value is defined it automatically traverses the element's
    hierarchy of parents, through any block elements and up to the form,
    searching for a defined value.

  render_data
    Usually called implicitly by "render". Returns the data structure that
    would normally be passed onto the "string" or "tt" render-methods.

    As with "render", you must call "process" once after building the form,
    and before calling "render_data".

  render_data_non_recursive
    Like "render_data", but doesn't include the data for any child-elements.

INTROSPECTION
  get_fields
    Arguments: [%options]

    Arguments: [\%options]

    Return Value: \@elements

    Returns all fields in the form (specifically, all elements which have a
    true "is_field" in HTML::FormFu::Element value).

    Accepts both "name" and "type" arguments to narrow the returned results.

        $form->get_fields({
            name => 'foo',
            type => 'Radio',
        });

    Accepts also an Regexp to search for results.

        $form->get_elements({
            name => qr/oo/,
        });

  get_field
    Arguments: [%options]

    Arguments: [\%options]

    Return Value: $element

    Accepts the same arguments as "get_fields", but only returns the first
    field found.

  get_elements
    Arguments: [%options]

    Arguments: [\%options]

    Return Value: \@elements

    Returns all top-level elements in the form (not recursive). See
    "get_all_elements" for a recursive version.

    Accepts both "name" and "type" arguments to narrow the returned results.

        $form->get_elements({
            name => 'foo',
            type => 'Radio',
        });

    Accepts also an Regexp to search for results.

        $form->get_elements({
            name => qr/oo/,
        });

  get_element
    Arguments: [%options]

    Arguments: [\%options]

    Return Value: $element

    Accepts the same arguments as "get_elements", but only returns the first
    element found.

    See "get_all_element" for a recursive version.

  get_all_elements
    Arguments: [%options]

    Arguments: [\%options]

    Return Value: \@elements

    Returns all elements in the form recursively.

    Optionally accepts both "name" and "type" arguments to narrow the
    returned results.

        # return all Text elements

        $form->get_all_elements({
            type => 'Text',
        });

    Accepts also an Regexp to search for results.

        $form->get_elements({
            name => qr/oo/,
        });

    See "get_elements" for a non-recursive version.

  get_all_element
    Arguments: [%options]

    Arguments: [\%options]

    Return Value: $element

    Accepts the same arguments as "get_all_elements", but only returns the
    first element found.

        # return the first Text field found, regardless of whether it's
        # within a fieldset or not

        $form->get_all_element({
            type => 'Text',
        });

    Accepts also an Regexp to search for results.

        $form->get_elements({
            name => qr/oo/,
        });

    See "get_all_elements" for a non-recursive version.

  get_deflators
    Arguments: [%options]

    Arguments: [\%options]

    Return Value: \@deflators

    Returns all top-level deflators from all fields.

    Accepts both "name" and "type" arguments to narrow the returned results.

        $form->get_deflators({
            name => 'foo',
            type => 'Strftime',
        });

  get_deflator
    Arguments: [%options]

    Arguments: [\%options]

    Return Value: $element

    Accepts the same arguments as "get_deflators", but only returns the
    first deflator found.

  get_filters
    Arguments: [%options]

    Arguments: [\%options]

    Return Value: \@filters

    Returns all top-level filters from all fields.

    Accepts both "name" and "type" arguments to narrow the returned results.

        $form->get_filters({
            name => 'foo',
            type => 'LowerCase',
        });

  get_filter
    Arguments: [%options]

    Arguments: [\%options]

    Return Value: $filter

    Accepts the same arguments as "get_filters", but only returns the first
    filter found.

  get_constraints
    Arguments: [%options]

    Arguments: [\%options]

    Return Value: \@constraints

    Returns all constraints from all fields.

    Accepts both "name" and "type" arguments to narrow the returned results.

        $form->get_constraints({
            name => 'foo',
            type => 'Equal',
        });

  get_constraint
    Arguments: [%options]

    Arguments: [\%options]

    Return Value: $constraint

    Accepts the same arguments as "get_constraints", but only returns the
    first constraint found.

  get_inflators
    Arguments: [%options]

    Arguments: [\%options]

    Return Value: \@inflators

    Returns all inflators from all fields.

    Accepts both "name" and "type" arguments to narrow the returned results.

        $form->get_inflators({
            name => 'foo',
            type => 'DateTime',
        });

  get_inflator
    Arguments: [%options]

    Arguments: [\%options]

    Return Value: $inflator

    Accepts the same arguments as "get_inflators", but only returns the
    first inflator found.

  get_validators
    Arguments: [%options]

    Arguments: [\%options]

    Return Value: \@validators

    Returns all validators from all fields.

    Accepts both "name" and "type" arguments to narrow the returned results.

        $form->get_validators({
            name => 'foo',
            type => 'Callback',
        });

  get_validator
    Arguments: [%options]

    Arguments: [\%options]

    Return Value: $validator

    Accepts the same arguments as "get_validators", but only returns the
    first validator found.

  get_transformers
    Arguments: [%options]

    Arguments: [\%options]

    Return Value: \@transformers

    Returns all transformers from all fields.

    Accepts both "name" and "type" arguments to narrow the returned results.

        $form->get_transformers({
            name => 'foo',
            type => 'Callback',
        });

  get_transformer
    Arguments: [%options]

    Arguments: [\%options]

    Return Value: $transformer

    Accepts the same arguments as "get_transformers", but only returns the
    first transformer found.

  clone
    Returns a deep clone of the <$form> object.

    Because of scoping issues, code references (such as in Callback
    constraints) are copied instead of cloned.

DEPRECATION POLICY
    We try our best to not make incompatible changes, but if they're
    required we'll make every effort possible to provide backwards
    compatibility for several release-cycles, issuing a warnings about the
    changes, before removing the legacy features.

REMOVED METHODS
    See also "REMOVED METHODS" in HTML::FormFu::Element.

  element_defaults
    Has been removed; see "default_args" instead.

  model_class
    Has been removed; use "default_model" instead.

  defaults_from_model
    Has been removed; use "default_values" in HTML::FormFu::Model instead.

  save_to_model
    Has been removed; use "update" in HTML::FormFu::Model instead.

BEST PRACTICES
    It is advisable to keep application-wide (or global) settings in a
    single config file, which should be loaded by each form.

    See "load_config_file".

COOKBOOK
    HTML::FormFu::Manual::Cookbook

  UNICODE
    HTML::FormFu::Manual::Unicode

EXAMPLES
  vertically-aligned CSS
    The distribution directory "examples/vertically-aligned" contains a form
    with example CSS for a "vertically aligned" theme.

    This can be viewed by opening the file "vertically-aligned.html" in a
    web-browser.

    If you wish to experiment with making changes, the form is defined in
    file "vertically-aligned.yml", and the HTML file can be updated with any
    changes by running the following command (while in the distribution root
    directory).

        perl examples/vertically-aligned/vertically-aligned.pl

    This uses the Template Toolkit file "vertically-aligned.tt", and the CSS
    is defined in files "vertically-aligned.css" and
    "vertically-aligned-ie.css".

SUPPORT
    Website:

    <http://www.formfu.org>

    Project Page:

    <http://code.google.com/p/html-formfu/>

    Mailing list:

    <http://lists.scsys.co.uk/cgi-bin/mailman/listinfo/html-formfu>

    Mailing list archives:

    <http://lists.scsys.co.uk/pipermail/html-formfu/>

    IRC:

    "irc.perl.org", channel "#formfu"

    The HTML::Widget archives
    <http://lists.scsys.co.uk/pipermail/html-widget/> between January and
    May 2007 also contain discussion regarding HTML::FormFu.

BUGS
    Please submit bugs / feature requests to
    <http://code.google.com/p/html-formfu/issues/list> (preferred) or
    <http://rt.perl.org>.

PATCHES
    To help patches be applied quickly, please send them to the mailing
    list; attached, rather than inline; against subversion, rather than a
    cpan version (run "svn diff > patchfile"); mention which svn version
    it's against. Mailing list messages are limited to 256KB, so gzip the
    patch if necessary.

GITHUB REPOSITORY
    This module's sourcecode is maintained in a git repository at
    <git://github.com/fireartist/HTML-FormFu.git>

    The project page is <https://github.com/fireartist/HTML-FormFu>

SEE ALSO
    HTML::FormFu::Imager

    Catalyst::Controller::HTML::FormFu

    HTML::FormFu::Model::DBIC

AUTHORS
    Carl Franks

CONTRIBUTORS
    Brian Cassidy

    Ozum Eldogan

    Ruben Fonseca

    Ronald Kimball

    Daisuke Maki

    Andreas Marienborg

    Mario Minati

    Steve Nolte

    Moritz Onken

    Doug Orleans

    Based on the original source code of HTML::Widget, by Sebastian Riedel,
    "sri@oook.de".

LICENSE
    This library is free software, you can redistribute it and/or modify it
    under the same terms as Perl itself.

PERL GAME
    Play the MMO written in perl: <http://www.lacunaexpanse.com>!

