Selectors

Seesaw supports general CSS-style selectors for finding and styling widgets in an app. The (seesaw.core/select) function supports locating a widget by :id as set at creation time:

(button :id :the-button :text "Push me")

   ... later ...

(listen (select root [:#the-button]) 
  :action (fn [e] ... do something ...))

Note that the first argument to (select) is always the root of the widget hierarchy to search from and the second argument is always a vector containing the selector. I wish the root wasn't necessary, but not requiring it makes it very difficult to support multiple instances of the same frame in one app. Suggestions welcome.

If (select) is given a simple id selector, like [:#my-id] it will always return a single widget for convenience. Otherwise, the return value is always a lazy sequence of widgets.

The "all" selector is also supported which will match everything in a sub-tree including the root. For example to disable an entire sub-tree:

(config! (select my-panel [:*]) :enabled? false)

Selectors follow the conventions established by [Enlive] (https://github.com/cgrand/enlive) with the following modifications:

• A "tag" selector, e.g. [:JLabel] matches the literal Java class name of the widget type.
• A full Java class can be matched with a selector like [:<javax.swing.JLabel>]. This will also match sub-classes of JLabel.
• An exact Java class can be matched by including an exclamation mark in a Java class selector: [:<javax.swing.JLabel!>].

See also A Brief Note on Seesaw Selectors and the documentation for (seesaw.core/select).