Coming from WordPress #

This page is for developers who know WordPress and start an Exponential project. It translates the WordPress concepts you use every day into their Exponential counterparts and points at the page that explains each. It compares concepts only; it does not rank the two systems, which are built for different starting points.

Contents #

1. The biggest difference
2. Concept by concept
3. Templates: from the template hierarchy to overrides
4. Queries: from WP_Query to fetch
5. Plugins and hooks: extensions, events and operators
6. Configuration and the command line
7. What to unlearn
8. Moving a WordPress site

The biggest difference #

WordPress starts from posts and pages and lets you add custom post types and custom fields on top, often through plugins. Exponential starts from a content model you define: every kind of content is a content class with typed attributes, and everything, from a page to an image or a user, is an object of a class placed in one content tree (The content model). Expect to spend the first day of a project on classes rather than on a theme.

Concept by concept #

Templates: from the template hierarchy to overrides #

WordPress picks a PHP template file by a naming hierarchy (single-{post_type}.php, page-{slug}.php and so on). Exponential's templates are written in its own template language (.tpl), not PHP, and a template is chosen by override rules in override.ini: "for node/view/full.tpl, when the class is exp_event, use full/exp_event.tpl". Rules can match the class, the node, the parent, the section, the depth, the view mode and more. The template language escapes output with |wash() and has no direct access to PHP, which keeps templates safe to hand to designers. Start with Templates and overrides for CMS developers; the language itself is in The template language.

Queries: from WP_Query to fetch #

Where a WordPress template calls WP_Query or get_posts(), an Exponential template calls a fetch function:

{def $events = fetch( 'content', 'list', hash(
        'parent_node_id', $node.node_id,
        'class_filter_type', 'include',
        'class_filter_array', array( 'exp_event' ),
        'sort_by', array( 'attribute', true(), 'exp_event/start_date' ),
        'limit', 10 ) )}

Fetches check permissions and hidden nodes for you. Details: Fetching content in templates; in PHP: Content from PHP.

Plugins and hooks: extensions, events and operators #

A WordPress plugin hooks into actions and filters. An Exponential extension is a folder under extension/ that can add settings, templates, modules (pages with their own URL), template operators, datatypes, workflow events, cronjobs and console commands. Instead of one hook system there are several precise extension points:

The whole list: Extension points at a glance.

Configuration and the command line #

What to unlearn #

• Do not query the database from templates or plugins. Use fetch functions and the kernel API; they keep permissions, versions, caches and search right.
• Do not put markup in content. Rich text is stored as XML and drawn by templates; editors choose structure, not HTML (Rich text).
• Do not edit shipped files. Kernel files and settings/*.ini are replaced on update; your work lives in your extension and in override settings.
• Clear the right cache. Templates, settings and content views are cached; Caching for CMS developers says which cache follows which change.

Moving a WordPress site #

The migration guide covers the WXR export, mapping, HTML to rich text, permalinks and redirects step by step: WordPress and Exponential. For the tools that import the result, see Importing content; the trainer's lesson is From WordPress.

Related pages #

• Exponential for CMS developers
• Mapping content to Exponential
• Moving from Smarty: if you know Smarty, the template language will look familiar
• Free documentation: this page is free to copy, translate and improve under the GNU FDL 1.3.