| 1 | | {{{ |
| 2 | | #!rst |
| 3 | | ================================== |
| 4 | | Generating Markup Programmatically |
| 5 | | ================================== |
| 6 | | |
| 7 | | Markup provides a ``builder`` module which lets you generate markup from Python |
| 8 | | code using a very simple syntax. The main entry point to the ``builder`` module |
| 9 | | is the ``tag`` object (which is actually an instance of the ``ElementFactory`` |
| 10 | | class). You should rarely (if ever) need to directly import and use any of the |
| 11 | | other classes in the ``builder`` module. |
| 12 | | |
| 13 | | |
| 14 | | .. contents:: Contents |
| 15 | | :depth: 2 |
| 16 | | .. sectnum:: |
| 17 | | |
| 18 | | |
| 19 | | Creating Elements |
| 20 | | ================= |
| 21 | | |
| 22 | | Elements can be created through the `tag` object using attribute access, for |
| 23 | | example:: |
| 24 | | |
| 25 | | >>> from markup.builder import tag |
| 26 | | >>> doc = tag.p('Some text and ', tag.a('a link', href='http://example.org/'), '.') |
| 27 | | >>> doc |
| 28 | | <Element "p"> |
| 29 | | |
| 30 | | This produces an ``Element`` instance which can be further modified to add child |
| 31 | | nodes and attributes. This is done by “calling” the element: positional |
| 32 | | arguments are added as child nodes (alternatively, the ``append`` method can be |
| 33 | | used for that purpose), whereas keywords arguments are added as attributes:: |
| 34 | | |
| 35 | | >>> doc(tag.br) |
| 36 | | <Element "p"> |
| 37 | | >>> print doc |
| 38 | | <p>Some text and <a href="http://example.org/">a link</a>.<br/></p> |
| 39 | | |
| 40 | | If an attribute name collides with a Python keyword, simply append an underscore |
| 41 | | to the name:: |
| 42 | | |
| 43 | | >>> doc(class_='intro') |
| 44 | | <Element "p"> |
| 45 | | >>> print doc |
| 46 | | <p class="intro">Some text and <a href="http://example.org/">a link</a>.<br/></p> |
| 47 | | |
| 48 | | As shown above, an ``Element`` can easily be directly rendered to XML text by |
| 49 | | printing it or using the Python ``str()`` function. This is basically a |
| 50 | | shortcut for converting the ``Element`` to a stream and serializing that |
| 51 | | stream:: |
| 52 | | |
| 53 | | >>> stream = doc.generate() |
| 54 | | >>> stream |
| 55 | | <markup.core.Stream object at 0x72d230> |
| 56 | | >>> print stream |
| 57 | | <p class="intro">Some text and <a href="http://example.org/">a link</a>.<br/></p> |
| 58 | | |
| 59 | | |
| 60 | | Creating Fragments |
| 61 | | ================== |
| 62 | | |
| 63 | | The ``tag`` object also allows creating “fragments”, which are basically lists |
| 64 | | of nodes (elements or text) that don't have a parent element. This can be useful |
| 65 | | for creating snippets of markup that are attached to a parent element later (for |
| 66 | | example in a template). Fragments are created by calling the ``tag`` object: |
| 67 | | |
| 68 | | >>> fragment = tag('Hello, ', tag.em('word'), '!') |
| 69 | | >>> fragment |
| 70 | | <Fragment> |
| 71 | | >>> print fragment |
| 72 | | Hello, <em>world</em>! |
| 73 | | }}} |
| | 1 | [[Include(trunk/doc/builder.txt)]] |
