Class: Ezamar::Morpher

Inherits:
Object show all
Defined in:
lib/ramaze/template/ezamar/morpher.rb

Overview

This applies a morphing-replace for the template.

To use the functionality of Morpher you will need to have hpricot installed, you will get one error in case you don’t and the method will be replaced by a stub that simply returns the template.

The method first checks if you use any morphers and just skips the step if you don’t, this should give quite some speedup for smaller templates that don’t use this functionality at all. the check works by searching the morphs with appended ‘=’ in the template. There may be a few cases where this won’t work since we cannot make any assumptions on the format.

If you want to turn this functionality off, either remove Morpher from:

Ramaze::Template::Ezamar::TRANSFORM_PIPELINE

or do:

Ramaze::Morpher::MORPHS.clear

The latter is a tad slower, but i mention the possibility in case you find good use for it.

You can add your own morphers in Ramaze::Morpher::MORPHS

For Example:

Morpher::MORPHS['if'] = '<?r %morph %expression ?>%content<?r end ?>'

Now, assuming that some tag in your template is ‘<a if=“@foo”>x</a>’

%morph stands for the name of your morph: ‘if’ %expression is the stuff you write in the attribute: ‘@foo’ %content is the tag without the attribute (and all inside): ‘<a>x</a>’

Constant Summary collapse

MORPHS =

Use this trait to define your custom morphs.

{
          'if'     => '<?r %morph %expression ?>%content<?r end ?>',
          'unless' => '<?r %morph %expression ?>%content<?r end ?>',
          'for'    => '<?r %morph %expression ?>%content<?r end ?>',
          'each'   => '<?r %expression.%morph do |_e| ?>%content<?r end ?>',
          'times'  => '<?r %expression.%morph do |_t| ?>%content<?r end ?>',
}

Class Method Summary collapse

Class Method Details

.transform(template) ⇒ Object

Since the functionality is best explained by examples, here they come.

Example:

if:

<div if="@name">#@name</div>

morphs to:

<?r if @name ?>
  <div>#@name</div>
<?r end ?>

unless:

<div unless="@name">No Name</div>

morphs to:

<?r unless @name ?>
  <div>No Name</div>
<?r end ?>

for:

<div for="name in @names">#{name}</div>

morphs to:

<?r for name in @names ?>
  <div>#{name}</div>
<?r end ?>

times:

<div times="3">#{_t}<div>

morphs to:

<?r 3.times do |_t| ?>
  <div>#{_t}</div>
<?r end ?>

each:

<div each="[1,2,3]">#{_e}</div>

morphs to:

<?r [1,2,3].each do |_e| ?>
  <div>#{_e}</div>
<?r end ?>

The latter two examples show you also one standard introduced by a limitation of the replacement-system.

When you yield a value, please name it by the first character(s) of the morphs name, with an underscore prefixed.

for each an _e, for times a _t.

This is by far not the best way to handle it and might lead to problems due to the lack of proper scoping in ruby (if you define an _e or _t before the block it will be overwritten).

So please be careful, I tried to come up with something that is both easy to write and doesn’t look outright awful while keeping an easy to remember mnemonic.

TODO:

- Add pure Ruby implementation as a fall-back.



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# File 'lib/ramaze/template/ezamar/morpher.rb', line 114

def self.transform(template)
  template = template.to_s
  hp = Hpricot(template)

  MORPHS.each do |morph, replacement|
    hp.search("[@#{morph}]") do |elem|
      expr = elem[morph]

      elem.remove_attribute(morph)

      repl = replacement.
        sub('%morph', morph).
        sub('%expression', expr).
        sub('%content', elem.to_html)

      elem.swap(repl)
    end
  end

  hp.to_html
end