1;
__END__
+
+=encoding utf-8
+
+=head1 NAME
+
+HTML::Element::Library - HTML::Element convenience functions
+
+=head1 SYNOPSIS
+
+ use HTML::Element::Library;
+ use HTML::TreeBuilder;
+
+=head1 DESCRIPTION
+
+This method provides API calls for common actions on trees when using
+L<HTML::Tree>.
+
+=head1 METHODS
+
+The test suite contains examples of each of these methods in a file
+C<t/$method.t>
+
+=head2 Positional Querying Methods
+
+=head3 $elem->siblings
+
+Return a list of all nodes under the same parent.
+
+=head3 $elem->sibdex
+
+Return the index of C<$elem> into the array of siblings of which it is
+a part. L<HTML::ElementSuper> calls this method C<addr> but I don't
+think that is a descriptive name. And such naming is deceptively close
+to the C<address> function of C<HTML::Element>. HOWEVER, in the
+interest of backwards compatibility, both methods are available.
+
+=head3 $elem->addr
+
+Same as sibdex
+
+=head3 $elem->position()
+
+Returns the coordinates of this element in the tree it inhabits. This
+is accomplished by succesively calling addr() on ancestor elements
+until either a) an element that does not support these methods is
+found, or b) there are no more parents. The resulting list is the
+n-dimensional coordinates of the element in the tree.
+
+=head2 Element Decoration Methods
+
+=head3 HTML::Element::Library::super_literal($text)
+
+In L<HTML::Element>, Sean Burke discusses super-literals. They are
+text which does not get escaped. Great for includng Javascript in
+HTML. Also great for including foreign language into a document.
+
+So, you basically toss C<super_literal> your text and back comes your
+text wrapped in a C<~literal> element.
+
+One of these days, I'll around to writing a nice C<EXPORT> section.
+
+=head2 Tree Rewriting Methods
+
+=head3 "de-prepping" HTML
+
+Oftentimes, the HTML to be worked with will have multiple sample rows:
+
+ <OL>
+ <LI>bread
+ <LI>butter
+ <LI>beer
+ <LI>bacon
+ </OL>
+
+But, before you begin to rewrite the HTML with your model data, you
+typically only want 1 or 2 sample rows.
+
+Thus, you want to "crunch" the multiple sample rows to a specified
+amount. Hence the C<crunch> method:
+
+ $tree->crunch(look_down => [ '_tag' => 'li' ], leave => 2) ;
+
+The C<leave> argument defaults to 1 if not given. The call above would
+"crunch" the above 4 sample rows to:
+
+ <OL>
+ <LI>bread
+ <LI>butter
+ </OL>
+
+=head3 Simplifying calls to HTML::FillInForm
+
+Since HTML::FillInForm gets and returns strings, using HTML::Element
+instances becomes tedious:
+
+ 1. Seamstress has an HTML tree that it wants the form filled in on
+ 2. Seamstress converts this tree to a string
+ 3. FillInForm parses the string into an HTML tree and then fills in the form
+ 4. FillInForm converts the HTML tree to a string
+ 5. Seamstress re-parses the HTML for additional processing
+
+I've filed a bug about this:
+L<https://rt.cpan.org/Ticket/Display.html?id=44105>
+
+This function, fillinform, allows you to pass a tree to fillinform
+(along with your data structure) and get back a tree:
+
+ my $new_tree = $html_tree->fillinform($data_structure);
+
+=head3 Mapping a hashref to HTML elements
+
+It is very common to get a hashref of data from some external source -
+flat file, database, XML, etc. Therefore, it is important to have a
+convenient way of mapping this data to HTML.
+
+As it turns out, there are 3 ways to do this in
+HTML::Element::Library. The most strict and structured way to do this
+is with C<content_handler>. Two other methods, C<hashmap> and
+C<datamap> require less manual mapping and may prove even more easy to
+use in certain cases.
+
+As is usual with Perl, a practical example is always best. So let's
+take some sample HTML:
+
+ <h1>user data</h1>
+ <span id="name">?</span>
+ <span id="email">?</span>
+ <span id="gender">?</span>
+
+Now, let's say our data structure is this:
+
+ $ref = { email => 'jim@beam.com', gender => 'lots' } ;
+
+And let's start with the most strict way to get what you want:
+
+ $tree->content_handler(email => $ref->{email} , gender => $ref->{gender}) ;
+
+In this case, you manually state the mapping between id tags and
+hashref keys and then C<content_handler> retrieves the hashref data
+and pops it in the specified place.
+
+Now let's look at the two (actually 2 and a half) other hash-mapping
+methods.
+
+ $tree->hashmap(id => $ref);
+
+Now, what this function does is super-destructive. It finds every
+element in the tree with an attribute named id (since 'id' is a
+parameter, it could find every element with some other attribute also)
+and replaces the content of those elements with the hashref value.
+
+So, in the case above, the
+
+ <span id="name">?</span>
+
+would come out as
+
+ <span id="name"></span>
+
+(it would be blank) - because there is nothing in the hash with that
+value, so it substituted
+
+ $ref->{name}
+
+which was blank and emptied the contents.
+
+Now, let's assume we want to protect name from being auto-assigned.
+Here is what you do:
+
+ $tree->hashmap(id => $ref, ['name']);
+
+That last array ref is an exclusion list.
+
+But wouldnt it be nice if you could do a hashmap, but only assigned
+things which are defined in the hashref? C<< defmap() >> to the
+rescue:
+
+ $tree->defmap(id => $ref);
+
+does just that, so
+
+ <span id="name">?</span>
+
+would be left alone.
+
+=head4 $elem->hashmap($attr_name, \%hashref, \@excluded, $debug)
+
+This method is designed to take a hashref and populate a series of
+elements. For example:
+
+ <table>
+ <tr sclass="tr" class="alt" align="left" valign="top">
+ <td smap="people_id">1</td>
+ <td smap="phone">(877) 255-3239</td>
+ <td smap="password">*********</td>
+ </tr>
+ </table>
+
+In the table above, there are several attributes named C<< smap >>. If
+we have a hashref whose keys are the same:
+
+ my %data = (people_id => 888, phone => '444-4444', password => 'dont-you-dare-render');
+
+Then a single API call allows us to populate the HTML while excluding
+those ones we dont:
+
+ $tree->hashmap(smap => \%data, ['password']);
+
+Note: the other way to prevent rendering some of the hash mapping is
+to not give that element the attr you plan to use for hash mapping.
+
+Also note: the function C<< hashmap >> has a simple easy-to-type API.
+Interally, it calls C<< hash_map >> (which has a more verbose keyword
+calling API). Thus, the above call to C<hashmap()> results in this
+call:
+
+ $tree->hash_map(hash => \%data, to_attr => 'sid', excluding => ['password']);
+
+=head4 $elem->defmap($attr_name, \%hashref, $debug)
+
+C<defmap> was described above.
+
+=head3 $elem->replace_content(@new_elem)
+
+Replaces all of C<$elem>'s content with C<@new_elem>.
+
+=head3 $elem->wrap_content($wrapper_element)
+
+Wraps the existing content in the provided element. If the provided
+element happens to be a non-element, a push_content is performed
+instead.
+
+=head3 $elem->set_child_content(@look_down, $content)
+
+This method looks down $tree using the criteria specified in
+@look_down using the the HTML::Element look_down() method.
+
+After finding the node, it detaches the node's content and pushes
+$content as the node's content.
+
+=head3 $tree->content_handler(%id_content)
+
+This is a convenience method. Because the look_down criteria will
+often simply be:
+
+ id => 'fixme'
+
+to find things like:
+
+ <a id=fixme href=http://www.somesite.org>replace_content</a>
+
+You can call this method to shorten your typing a bit. You can simply
+type
+
+ $elem->content_handler( fixme => 'new text' )
+
+Instead of typing:
+
+ $elem->set_child_content(sid => 'fixme', 'new text')
+
+ALSO NOTE: you can pass a hash whose keys are C<id>s and whose values
+are the content you want there and it will perform the replacement on
+each hash member:
+
+ my %id_content = (name => "Terrence Brannon",
+ email => 'tbrannon@in.com',
+ balance => 666,
+ content => $main_content);
+ $tree->content_handler(%id_content);
+
+=head3 $tree->highlander($subtree_span_id, $conditionals, @conditionals_args)
+
+This allows for "if-then-else" style processing. Highlander was a
+movie in which only one would survive. Well, in terms of a tree when
+looking at a structure that you want to process in C<if-then-else>
+style, only one child will survive. For example, given this HTML
+template:
+
+ <span klass="highlander" id="age_dialog">
+ <span id="under10">
+ Hello, does your mother know you're
+ using her AOL account?
+ </span>
+ <span id="under18">
+ Sorry, you're not old enough to enter
+ (and too dumb to lie about your age)
+ </span>
+ <span id="welcome">
+ Welcome
+ </span>
+ </span>
+
+We only want one child of the C<span> tag with id C<age_dialog> to
+remain based on the age of the person visiting the page.
+
+So, let's setup a call that will prune the subtree as a function of
+age:
+
+ sub process_page {
+ my $age = shift;
+ my $tree = HTML::TreeBuilder->new_from_file('t/html/highlander.html');
+
+ $tree->highlander
+ (age_dialog =>
+ [
+ under10 => sub { $_[0] < 10},
+ under18 => sub { $_[0] < 18},
+ welcome => sub { 1 }
+ ],
+ $age
+ );
+
+And there we have it. If the age is less than 10, then the node with
+id C<under10> remains. For age less than 18, the node with id
+C<under18> remains. Otherwise our "else" condition fires and the child
+with id C<welcome> remains.
+
+=head3 $tree->passover(@id_of_element)
+
+In some cases, you know exactly which element(s) should survive. In
+this case, you can simply call C<passover> to remove it's (their)
+siblings. For the HTML above, you could delete C<under10> and
+C<welcome> by simply calling:
+
+ $tree->passover('under18');
+
+Because passover takes an array, you can specify several children to
+preserve.
+
+=head3 $tree->highlander2($tree, $conditionals, @conditionals_args)
+
+Right around the same time that C<table2()> came into being,
+Seamstress began to tackle tougher and tougher processing problems. It
+became clear that a more powerful highlander was needed... one that
+not only snipped the tree of the nodes that should not survive, but
+one that allows for post-processing of the survivor node. And one that
+was more flexible with how to find the nodes to snip.
+
+Thus (drum roll) C<highlander2()>.
+
+So let's look at our HTML which requires post-selection processing:
+
+ <span klass="highlander" id="age_dialog">
+ <span id="under10">
+ Hello, little <span id=age>AGE</span>-year old,
+ does your mother know you're using her AOL account?
+ </span>
+ <span id="under18">
+ Sorry, you're only <span id=age>AGE</span>
+ (and too dumb to lie about your age)
+ </span>
+ <span id="welcome">
+ Welcome, isn't it good to be <span id=age>AGE</span> years old?
+ </span>
+</span>
+
+In this case, a branch survives, but it has dummy data in it. We must
+take the surviving segment of HTML and rewrite the age C<span> with
+the age. Here is how we use C<highlander2()> to do so:
+
+ sub replace_age {
+ my $branch = shift;
+ my $age = shift;
+ $branch->look_down(id => 'age')->replace_content($age);
+ }
+
+ my $if_then = $tree->look_down(id => 'age_dialog');
+
+ $if_then->highlander2(
+ cond => [
+ under10 => [
+ sub { $_[0] < 10} ,
+ \&replace_age
+ ],
+ under18 => [
+ sub { $_[0] < 18} ,
+ \&replace_age
+ ],
+ welcome => [
+ sub { 1 },
+ \&replace_age
+ ]
+ ],
+ cond_arg => [ $age ]
+ );
+
+We pass it the tree (C<$if_then>), an arrayref of conditions (C<cond>)
+and an arrayref of arguments which are passed to the C<cond>s and to
+the replacement subs.
+
+The C<under10>, C<under18> and C<welcome> are id attributes in the
+tree of the siblings of which only one will survive. However, should
+you need to do more complex look-downs to find the survivor, then
+supply an array ref instead of a simple scalar:
+
+ $if_then->highlander2(
+ cond => [
+ [class => 'r12'] => [
+ sub { $_[0] < 10} ,
+ \&replace_age
+ ],
+ [class => 'z22'] => [
+ sub { $_[0] < 18} ,
+ \&replace_age
+ ],
+ [class => 'w88'] => [
+ sub { 1 },
+ \&replace_age
+ ]
+ ],
+ cond_arg => [ $age ]
+ );
+
+=head3 $tree->overwrite_attr($mutation_attr => $mutating_closures)
+
+This method is designed for taking a tree and reworking a set of nodes
+in a stereotyped fashion. For instance let's say you have 3 remote
+image archives, but you don't want to put long URLs in your img src
+tags for reasons of abstraction, re-use and brevity. So instead you do
+this:
+
+ <img src="/img/smiley-face.jpg" fixup="src lnc">
+ <img src="/img/hot-babe.jpg" fixup="src playboy">
+ <img src="/img/footer.jpg" fixup="src foobar">
+
+and then when the tree of HTML is being processed, you make this call:
+
+ my %closures = (
+ lnc => sub { my ($tree, $mute_node, $attr_value)= @_; "http://lnc.usc.edu$attr_value" },
+ playboy => sub { my ($tree, $mute_node, $attr_value)= @_; "http://playboy.com$attr_value" }
+ foobar => sub { my ($tree, $mute_node, $attr_value)= @_; "http://foobar.info$attr_value" }
+ )
+
+ $tree->overwrite_attr(fixup => \%closures) ;
+
+and the tags come out modified like so:
+
+ <img src="http://lnc.usc.edu/img/smiley-face.jpg" fixup="src lnc">
+ <img src="http://playboy.com/img/hot-babe.jpg" fixup="src playboy">
+ <img src="http://foobar.info/img/footer.jpg" fixup="src foobar">
+
+=head3 $tree->mute_elem($mutation_attr => $mutating_closures, [ $post_hook ] )
+
+This is a generalization of C<overwrite_attr>. C<overwrite_attr>
+assumes the return value of the closure is supposed overwrite an
+attribute value and does it for you. C<mute_elem> is a more general
+function which does nothing but hand the closure the element and let
+it mutate it as it jolly well pleases :)
+
+In fact, here is the implementation of C<overwrite_attr> to give you a
+taste of how C<mute_attr> is used:
+
+ sub overwrite_action {
+ my ($mute_node, %X) = @_;
+
+ $mute_node->attr($X{local_attr}{name} => $X{local_attr}{value}{new});
+ }
+
+
+ sub HTML::Element::overwrite_attr {
+ my $tree = shift;
+
+ $tree->mute_elem(@_, \&overwrite_action);
+ }
+
+=head2 Tree-Building Methods
+
+=head3 Unrolling an array via a single sample element (<ul> container)
+
+This is best described by example. Given this HTML:
+
+ <strong>Here are the things I need from the store:</strong>
+ <ul>
+ <li class="store_items">Sample item</li>
+ </ul>
+
+We can unroll it like so:
+
+ my $li = $tree->look_down(class => 'store_items');
+
+ my @items = qw(bread butter vodka);
+
+ $tree->iter($li => @items);
+
+To produce this:
+
+ <html>
+ <head></head>
+ <body>Here are the things I need from the store:
+ <ul>
+ <li class="store_items">bread</li>
+ <li class="store_items">butter</li>
+ <li class="store_items">vodka</li>
+ </ul>
+ </body>
+ </html>
+
+Now, you might be wondering why the API call is:
+
+ $tree->iter($li => @items)
+
+instead of:
+
+ $li->iter(@items)
+
+and there is no good answer. The latter would be more concise and it
+is what I should have done.
+
+=head3 Unrolling an array via n sample elements (<dl> container)
+
+C<iter()> was fine for awhile, but some things (e.g. definition lists)
+need a more general function to make them easy to do. Hence
+C<iter2()>. This function will be explained by example of unrolling a
+simple definition list.
+
+So here's our mock-up HTML from the designer:
+
+ <dl class="dual_iter" id="service_plan">
+ <dt>Artist</dt>
+ <dd>A person who draws blood.</dd>
+
+ <dt>Musician</dt>
+ <dd>A clone of Iggy Pop.</dd>
+
+ <dt>Poet</dt>
+ <dd>A relative of Edgar Allan Poe.</dd>
+
+ <dt class="adstyle">sample header</dt>
+ <dd class="adstyle2">sample data</dd>
+</dl>
+
+
+And we want to unroll our data set:
+
+ my @items = (
+ ['the pros' => 'never have to worry about service again'],
+ ['the cons' => 'upfront extra charge on purchase'],
+ ['our choice' => 'go with the extended service plan']
+ );
+
+
+Now, let's make this problem a bit harder to show off the power of
+C<iter2()>. Let's assume that we want only the last <dt> and it's
+accompanying <dd> (the one with "sample data") to be used as the
+sample data for unrolling with our data set. Let's further assume that
+we want them to remain in the final output.
+
+So now, the API to C<iter2()> will be discussed and we will explain
+how our goal of getting our data into HTML fits into the API.
+
+=over 4
+
+=item * wrapper_ld
+
+This is how to look down and find the container of all the elements we
+will be unrolling. The <dl> tag is the container for the dt and dd
+tags we will be unrolling.
+
+If you pass an anonymous subroutine, then it is presumed that
+execution of this subroutine will return the HTML::Element
+representing the container tag. If you pass an array ref, then this
+will be dereferenced and passed to C<HTML::Element::look_down()>.
+
+default value: C<< ['_tag' => 'dl'] >>
+
+Based on the mock HTML above, this default is fine for finding our
+container tag. So let's move on.
+
+=item * wrapper_data
+
+This is an array reference of data that we will be putting into the
+container. You must supply this. C<@items> above is our
+C<wrapper_data>.
+
+=item * wrapper_proc
+
+After we find the container via C<wrapper_ld>, we may want to
+pre-process some aspect of this tree. In our case the first two sets
+of dt and dd need to be removed, leaving the last dt and dd. So, we
+supply a C<wrapper_proc> which will do this.
+
+default: undef
+
+=item * item_ld
+
+This anonymous subroutine returns an array ref of C<HTML::Element>s
+that will be cloned and populated with item data (item data is a "row"
+of C<wrapper_data>).
+
+default: returns an arrayref consisting of the dt and dd element
+inside the container.
+
+=item * item_data
+
+This is a subroutine that takes C<wrapper_data> and retrieves one
+"row" to be "pasted" into the array ref of C<HTML::Element>s found via
+C<item_ld>. I hope that makes sense.
+
+default: shifts C<wrapper_data>.
+
+=item * item_proc
+
+This is a subroutine that takes the C<item_data> and the
+C<HTML::Element>s found via C<item_ld> and produces an arrayref of
+C<HTML::Element>s which will eventually be spliced into the container.
+
+Note that this subroutine MUST return the new items. This is done So
+that more items than were passed in can be returned. This is useful
+when, for example, you must return 2 dts for an input data item. And
+when would you do this? When a single term has multiple spellings for
+instance.
+
+default: expects C<item_data> to be an arrayref of two elements and
+C<item_elems> to be an arrayref of two C<HTML::Element>s. It replaces
+the content of the C<HTML::Element>s with the C<item_data>.
+
+=item * splice
+
+After building up an array of C<@item_elems>, the subroutine passed as
+C<splice> will be given the parent container HTML::Element and the
+C<@item_elems>. How the C<@item_elems> end up in the container is up
+to this routine: it could put half of them in. It could unshift them
+or whatever.
+
+default: C<< $container->splice_content(0, 2, @item_elems) >> In other
+words, kill the 2 sample elements with the newly generated @item_elems
+
+=back
+
+So now that we have documented the API, let's see the call we need:
+
+ $tree->iter2(
+ # default wrapper_ld ok.
+ wrapper_data => \@items,
+ wrapper_proc => sub {
+ my ($container) = @_;
+
+ # only keep the last 2 dts and dds
+ my @content_list = $container->content_list;
+ $container->splice_content(0, @content_list - 2);
+ },
+
+ # default item_ld is fine.
+ # default item_data is fine.
+ # default item_proc is fine.
+ splice => sub {
+ my ($container, @item_elems) = @_;
+ $container->unshift_content(@item_elems);
+ },
+ debug => 1,
+ );
+
+=head3 Select Unrolling
+
+The C<unroll_select> method has this API:
+
+ $tree->unroll_select(
+ select_label => $id_label,
+ option_value => $closure, # how to get option value from data row
+ option_content => $closure, # how to get option content from data row
+ option_selected => $closure, # boolean to decide if SELECTED
+ data => $data # the data to be put into the SELECT
+ data_iter => $closure # the thing that will get a row of data
+ debug => $boolean,
+ append => $boolean, # remove the sample <OPTION> data or append?
+ );
+
+Here's an example:
+
+ $tree->unroll_select(
+ select_label => 'clan_list',
+ option_value => sub { my $row = shift; $row->clan_id },
+ option_content => sub { my $row = shift; $row->clan_name },
+ option_selected => sub { my $row = shift; $row->selected },
+ data => \@query_results,
+ data_iter => sub { my $data = shift; $data->next },
+ append => 0,
+ debug => 0
+ );
+
+=head2 Tree-Building Methods: Table Generation
+
+Matthew Sisk has a much more intuitive (imperative) way to generate
+tables via his module L<HTML::ElementTable|HTML::ElementTable>.
+
+However, for those with callback fever, the following method is
+available. First, we look at a nuts and bolts way to build a table
+using only standard L<HTML::Tree> API calls. Then the C<table> method
+available here is discussed.
+
+=head3 Sample Model
+
+ package Simple::Class;
+
+ use Set::Array;
+
+ my @name = qw(bob bill brian babette bobo bix);
+ my @age = qw(99 12 44 52 12 43);
+ my @weight = qw(99 52 80 124 120 230);
+
+
+ sub new {
+ my $this = shift;
+ bless {}, ref($this) || $this;
+ }
+
+ sub load_data {
+ my @data;
+
+ for (0 .. 5) {
+ push @data, {
+ age => $age[rand $#age] + int rand 20,
+ name => shift @name,
+ weight => $weight[rand $#weight] + int rand 40
+ }
+ }
+
+ Set::Array->new(@data);
+ }
+
+ 1;
+
+=head4 Sample Usage:
+
+ my $data = Simple::Class->load_data;
+ ++$_->{age} for @$data
+
+=head3 Inline Code to Unroll a Table
+
+=head4 HTML
+
+ <html>
+ <table id="load_data">
+ <tr> <th>name</th><th>age</th><th>weight</th> </tr>
+ <tr id="iterate">
+ <td id="name"> NATURE BOY RIC FLAIR </td>
+ <td id="age"> 35 </td>
+ <td id="weight"> 220 </td>
+ </tr>
+ </table>
+ </html>
+
+
+=head4 The manual way (*NOT* recommended)
+
+ require 'simple-class.pl';
+ use HTML::Seamstress;
+
+ # load the view
+ my $seamstress = HTML::Seamstress->new_from_file('simple.html');
+
+ # load the model
+ my $o = Simple::Class->new;
+ my $data = $o->load_data;
+
+ # find the <table> and <tr>
+ my $table_node = $seamstress->look_down('id', 'load_data');
+ my $iter_node = $table_node->look_down('id', 'iterate');
+ my $table_parent = $table_node->parent;
+
+
+ # drop the sample <table> and <tr> from the HTML
+ # only add them in if there is data in the model
+ # this is achieved via the $add_table flag
+
+ $table_node->detach;
+ $iter_node->detach;
+ my $add_table;
+
+ # Get a row of model data
+ while (my $row = shift @$data) {
+
+ # We got row data. Set the flag indicating ok to hook the table into the HTML
+ ++$add_table;
+
+ # clone the sample <tr>
+ my $new_iter_node = $iter_node->clone;
+
+ # find the tags labeled name age and weight and
+ # set their content to the row data
+ $new_iter_node->content_handler($_ => $row->{$_})
+ for qw(name age weight);
+
+ $table_node->push_content($new_iter_node);
+
+ }
+
+ # reattach the table to the HTML tree if we loaded data into some table rows
+
+ $table_parent->push_content($table_node) if $add_table;
+
+ print $seamstress->as_HTML;
+
+=head3 $tree->table() : API call to Unroll a Table
+
+ require 'simple-class.pl';
+ use HTML::Seamstress;
+
+ # load the view
+ my $seamstress = HTML::Seamstress->new_from_file('simple.html');
+ # load the model
+ my $o = Simple::Class->new;
+
+ $seamstress->table
+ (
+ # tell seamstress where to find the table, via the method call
+ # ->look_down('id', $gi_table). Seamstress detaches the table from the
+ # HTML tree automatically if no table rows can be built
+
+ gi_table => 'load_data',
+
+ # tell seamstress where to find the tr. This is a bit useless as
+ # the <tr> usually can be found as the first child of the parent
+
+ gi_tr => 'iterate',
+
+ # the model data to be pushed into the table
+
+ table_data => $o->load_data,
+
+ # the way to take the model data and obtain one row
+ # if the table data were a hashref, we would do:
+ # my $key = (keys %$data)[0]; my $val = $data->{$key}; delete $data->{$key}
+
+ tr_data => sub {
+ my ($self, $data) = @_;
+ shift @{$data} ;
+ },
+
+ # the way to take a row of data and fill the <td> tags
+
+ td_data => sub {
+ my ($tr_node, $tr_data) = @_;
+ $tr_node->content_handler($_ => $tr_data->{$_})
+ for qw(name age weight)
+ }
+ );
+
+ print $seamstress->as_HTML;
+
+=head4 Looping over Multiple Sample Rows
+
+* HTML
+
+ <html>
+ <table id="load_data" CELLPADDING=8 BORDER=2>
+ <tr> <th>name</th><th>age</th><th>weight</th> </tr>
+ <tr id="iterate1" BGCOLOR="white" >
+ <td id="name"> NATURE BOY RIC FLAIR </td>
+ <td id="age"> 35 </td>
+ <td id="weight"> 220 </td>
+ </tr>
+ <tr id="iterate2" BGCOLOR="#CCCC99">
+ <td id="name"> NATURE BOY RIC FLAIR </td>
+ <td id="age"> 35 </td>
+ <td id="weight"> 220 </td>
+ </tr>
+ </table>
+</html>
+
+* Only one change to last API call.
+
+This:
+
+ gi_tr => 'iterate',
+
+becomes this:
+
+ gi_tr => ['iterate1', 'iterate2']
+
+=head3 $tree->table2() : New API Call to Unroll a Table
+
+After 2 or 3 years with C<table()>, I began to develop production
+websites with it and decided it needed a cleaner interface,
+particularly in the area of handling the fact that C<id> tags will be
+the same after cloning a table row.
+
+First, I will give a dry listing of the function's argument
+parameters. This will not be educational most likely. A better way to
+understand how to use the function is to read through the incremental
+unrolling of the function's interface given in conversational style
+after the dry listing. But take your pick. It's the same information
+given in two different ways.
+
+=head4 Dry/technical parameter documentation
+
+C<< $tree->table2(%param) >> takes the following arguments:
+
+=over
+
+=item * C<< table_ld => $look_down >> : optional
+
+How to find the C<table> element in C<$tree>. If C<$look_down> is an
+arrayref, then use C<look_down>. If it is a CODE ref, then call it,
+passing it C<$tree>.
+
+Defaults to C<< ['_tag' => 'table'] >> if not passed in.
+
+=item * C<< table_data => $tabular_data >> : required
+
+The data to fill the table with. I<Must> be passed in.
+
+=item * C<< table_proc => $code_ref >> : not implemented
+
+A subroutine to do something to the table once it is found. Not
+currently implemented. Not obviously necessary. Just created because
+there is a C<tr_proc> and C<td_proc>.
+
+=item * C<< tr_ld => $look_down >> : optional
+
+Same as C<table_ld> but for finding the table row elements. Please
+note that the C<tr_ld> is done on the table node that was found
+I<instead> of the whole HTML tree. This makes sense. The C<tr>s that
+you want exist below the table that was just found.
+
+Defaults to C<< ['_tag' => 'tr'] >> if not passed in.
+
+=item * C<< tr_data => $code_ref >> : optional
+
+How to take the C<table_data> and return a row. Defaults to:
+
+ sub { my ($self, $data) = @_;
+ shift(@{$data}) ;
+ }
+
+=item * C<< tr_proc => $code_ref >> : optional
+
+Something to do to the table row we are about to add to the table we
+are making. Defaults to a routine which makes the C<id> attribute
+unique:
+
+ sub {
+ my ($self, $tr, $tr_data, $tr_base_id, $row_count) = @_;
+ $tr->attr(id => sprintf "%s_%d", $tr_base_id, $row_count);
+ }
+
+=item * C<< td_proc => $code_ref >> : required
+
+This coderef will take the row of data and operate on the C<td> cells
+that are children of the C<tr>. See C<t/table2.t> for several usage
+examples.
+
+Here's a sample one:
+
+ sub {
+ my ($tr, $data) = @_;
+ my @td = $tr->look_down('_tag' => 'td');
+ for my $i (0..$#td) {
+ $td[$i]->splice_content(0, 1, $data->[$i]);
+ }
+ }
+
+=back
+
+=head4 Conversational parameter documentation
+
+The first thing you need is a table. So we need a look down for that.
+If you don't give one, it defaults to
+
+ ['_tag' => 'table']
+
+What good is a table to display in without data to display?! So you
+must supply a scalar representing your tabular data source. This
+scalar might be an array reference, a C<next>able iterator, a DBI
+statement handle. Whatever it is, it can be iterated through to build
+up rows of table data. These two required fields (the way to find the
+table and the data to display in the table) are C<table_ld> and
+C<table_data> respectively. A little more on C<table_ld>. If this
+happens to be a CODE ref, then execution of the code ref is presumed
+to return the C<HTML::Element> representing the table in the HTML
+tree.
+
+Next, we get the row or rows which serve as sample C<tr> elements by
+doing a C<look_down> from the C<table_elem>. While normally one sample
+row is enough to unroll a table, consider when you have alternating
+table rows. This API call would need one of each row so that it can
+cycle through the sample rows as it loops through the data.
+Alternatively, you could always just use one row and make the
+necessary changes to the single C<tr> row by mutating the element in
+C<tr_proc>, discussed below. The default C<tr_ld> is C<< ['_tag' =>
+'tr'] >> but you can overwrite it. Note well, if you overwrite it with
+a subroutine, then it is expected that the subroutine will return the
+C<HTML::Element>(s) which are C<tr> element(s). The reason a
+subroutine might be preferred is in the case that the HTML designers
+gave you 8 sample C<tr> rows but only one prototype row is needed. So
+you can write a subroutine, to splice out the 7 rows you don't need
+and leave the one sample row remaining so that this API call can clone
+it and supply it to the C<tr_proc> and C<td_proc> calls.
+
+Now, as we move through the table rows with table data, we need to do
+two different things on each table row:
+
+=over 4
+
+=item * get one row of data from the C<table_data> via C<tr_data>
+
+The default procedure assumes the C<table_data> is an array reference
+and shifts a row off of it:
+
+ sub {
+ my ($self, $data) = @_;
+ shift @{$data};
+ }
+
+Your function MUST return undef when there is no more rows to lay out.
+
+=item * take the C<tr> element and mutate it via C<tr_proc>
+
+The default procedure simply makes the id of the table row unique:
+
+ sub {
+ my ($self, $tr, $tr_data, $row_count, $root_id) = @_;
+ $tr->attr(id => sprintf "%s_%d", $root_id, $row_count);
+ }
+
+=back
+
+Now that we have our row of data, we call C<td_proc> so that it can
+take the data and the C<td> cells in this C<tr> and process them. This
+function I<must> be supplied.
+
+=head3 Whither a Table with No Rows
+
+Often when a table has no rows, we want to display a message
+indicating this to the view. Use conditional processing to decide what
+to display:
+
+ <span id=no_data>
+ <table><tr><td>No Data is Good Data</td></tr></table>
+ </span>
+ <span id=load_data>
+ <html>
+ <table id="load_data">
+ <tr> <th>name</th><th>age</th><th>weight</th> </tr>
+ <tr id="iterate">
+ <td id="name"> NATURE BOY RIC FLAIR </td>
+ <td id="age"> 35 </td>
+ <td id="weight"> 220 </td>
+ </tr>
+ </table>
+ </html>
+ </span>
+
+=head2 Tree-Killing Methods
+
+=head3 $tree->prune
+
+This removes any nodes from the tree which consist of nothing or
+nothing but whitespace. See also delete_ignorable_whitespace in
+L<HTML::Element>.
+
+=head2 Loltree Functions
+
+A loltree is an arrayref consisting of arrayrefs which is used by C<<
+new_from__lol >> in L<HTML::Element> to produce HTML trees. The CPAN
+distro L<XML::Element::Tolol> creates such XML trees by parsing XML
+files, analagous to L<XML::Toolkit>. The purpose of the functions in
+this section is to allow you manipulate a loltree programmatically.
+
+These could not be methods because if you bless a loltree, then
+HTML::Tree will barf.
+
+=head3 HTML::Element::newchild($lol, $parent_label, @newchild)
+
+Given this initial loltree:
+
+ my $initial_lol = [ note => [ shopping => [ item => 'sample' ] ] ];
+
+This code:
+
+ sub shopping_items {
+ my @shopping_items = map { [ item => _ ] } qw(bread butter beans);
+ @shopping_items;
+ }
+
+ my $new_lol = HTML::Element::newnode($initial_lol, item => shopping_items());
+
+ will replace the single sample with a list of shopping items:
+
+ [
+ 'note',
+ [
+ 'shopping',
+ [
+ 'item',
+ 'bread'
+ ],
+ [
+ 'item',
+ 'butter'
+ ],
+ [
+ 'item',
+ 'beans'
+ ]
+
+ ]
+ ];
+
+Thanks to kcott and the other Perlmonks in this thread:
+http://www.perlmonks.org/?node_id=912416
+
+
+=head1 SEE ALSO
+
+=head2 L<HTML::Tree>
+
+A perl package for creating and manipulating HTML trees.
+
+=head2 L<HTML::ElementTable>
+
+An L<HTML::Tree> - based module which allows for manipulation of HTML
+trees using cartesian coordinations.
+
+=head2 L<HTML::Seamstress>
+
+An L<HTML::Tree> - based module inspired by XMLC
+(L<http://xmlc.enhydra.org>), allowing for dynamic HTML generation via
+tree rewriting.
+
+=head2 Push-style templating systems
+
+A comprehensive cross-language
+L<list of push-style templating systems|http://perlmonks.org/?node_id=674225>.
+
+=head1 TODO
+
+=over
+
+=item * highlander2
+
+currently the API expects the subtrees to survive or be pruned to be
+identified by id:
+
+ $if_then->highlander2([
+ under10 => sub { $_[0] < 10} ,
+ under18 => sub { $_[0] < 18} ,
+ welcome => [
+ sub { 1 },
+ sub {
+ my $branch = shift;
+ $branch->look_down(id => 'age')->replace_content($age);
+ }
+ ]
+ ], $age);
+
+but, it should be more flexible. the C<under10>, and C<under18> are
+expected to be ids in the tree... but it is not hard to have a check
+to see if this field is an array reference and if it, then to do a
+look down instead:
+
+ $if_then->highlander2([
+ [class => 'under10'] => sub { $_[0] < 10} ,
+ [class => 'under18'] => sub { $_[0] < 18} ,
+ [class => 'welcome'] => [
+ sub { 1 },
+ sub {
+ my $branch = shift;
+ $branch->look_down(id => 'age')->replace_content($age);
+ }
+ ]
+ ], $age);
+
+=back
+
+=head1 AUTHOR
+
+Original author Terrence Brannon, E<lt>tbone@cpan.orgE<gt>.
+
+Adopted by Marius Gavrilescu C<< <marius@ieval.ro> >>.
+
+I appreciate the feedback from M. David Moussa Leo Keita regarding
+some issues with the test suite, namely (1) CRLF leading to test
+breakage in F<t/crunch.t> and (2) using the wrong module in
+F<t/prune.t> thus not having the right functionality available.
+
+Many thanks to BARBIE for his RT bug report.
+
+Many thanks to perlmonk kcott for his work on array rewriting:
+L<http://www.perlmonks.org/?node_id=912416>. It was crucial in the
+development of newchild.
+
+=head1 COPYRIGHT AND LICENSE
+
+Coypright (C) 2014 by Marius Gavrilescu
+
+Copyright (C) 2004-2012 by Terrence Brannon
+
+This library is free software; you can redistribute it and/or modify
+it under the same terms as Perl itself, either Perl version 5.8.4 or,
+at your option, any later version of Perl 5 you may have available.
+
+
+=cut
projects / html-element-library.git / blobdiff