wiki.opajs

wiki.js

/**
 * {1 Database and database interaction}
 */

/**
 * Contents of the wiki.
 *
 * Pages which do not exist have content "This page is empty".
 * Note: By definition, pages stored in the database are always well-formed.
 */
db {
  Template.default_content /wiki[string]
  /wiki[_] = Template.text("This page is empty")
}

/**
 * Read the content associated to a topic from the database and return the
 * corresponding source code.
 *
 * @param topic A topic (arbitrary string).
 * @return If a page has been saved in for [topic], the source code for this
 * page. Otherwise, the source code for the default page.
 */
@publish load_source(topic) { Template.to_source(Template.default, /wiki[topic]) }

/**
 * Read the content associated to a topic from the database and return the
 * corresponding xhtml, ready to insert.
 *
 * @param topic A topic (arbitrary string).
 * @return If a page has been saved in for [topic], the xhtml for this
 * page. Otherwise, the xhtml for the default page.
 *
 * Note: This function does not perform any caching.
 */
@publish load_rendered(topic) { Template.to_xhtml( Template.default, /wiki[topic]) }

/**
 * Accept source code, save the corresponding document in the database.
 *
 * @param topic A topic (arbitrary string).
 * @param source Source code to store at this topic. If this source code
 * is syntactically valid, store the template datastructure
 * corresponding to its content [Template.content].
 * Otherwise, the source code is implicitly replaced by the document
 * representing this raw code and this document is saved in the database.
 *
 * @return In case of success, the xhtml for the page that has just been
 * saved. In case of failure, an error message.
 */
@publish save_source(topic, source) {
    match (Template.try_parse(Template.default, source)) {
       case ~{success} =>
            /wiki[topic] <- success;
            Template.to_xhtml(Template.default, success)
       case {failure: *} =>
            /wiki[topic] <- Template.text(source);
            <>Error: {source}</>
    }
}

/**
 * {1 User interface}
 */

/**
 * Set the user interface in edition mode.
 *
 * Load the source code for a topic, display an editable zone for this source code.
 *
 * @param topic The topic to edit.
 */
edit(topic) {
    Dom.set_value(#edit_content, load_source(topic));
    Dom.hide(#show_content);
    Dom.show(#edit_content);
    Dom.give_focus(#edit_content);
    void
}

/**
 * Set the user interface in reading mode.
 *
 * Save the source code for a topic (extracted from [#edit_content]),
 * display the rendered version.
 *
 * @param topic The topic to save.
 */
save(topic) {
    content = save_source(topic, Dom.get_value(#edit_content));
    Dom.transform([#show_content <- content]);
    Dom.hide(#edit_content);
    Dom.show(#show_content);
    void
}

/**
 * Main user interface
 *
 * @param topic The topic being consulted
 * @retrn A resource, ready to be passed to a dispatcher.
 */
display(topic) {
   Resource.styled_page("About {topic}", ["/resources/css.css"],
     <div id=#header><div id=#logo></div>About {topic}</div>
     <div class="show_content" id=#show_content ondblclick={_ -> edit(topic)}>{load_rendered(topic)}</>
     <textarea class="edit_content" id=#edit_content style="display:none" cols="40" rows="30" onblur={_ -> save(topic)}></>
   )
}

/**
 * {1 Main application}
 */

/**
 * Dispatch requests to the user interface
 *
 * Note: The empty request is dispatched as if it were "Hello".
 */
start(x) {
  match(x) {
    case {path: [], ... } => display("Hello");
    case {~path,     ...} => display(String.capitalize(String.to_lower(List.to_string_using("", "", "::", path))));
  }
}

/**
 * Statically embed a bundle of resources
 */
start_server(Server.of_bundle([@static_include_directory("resources")]));

/**
 * Launch the [start] dispatcher
 */
start_server(Server.simple_dispatch(start));