Hafni is a java swing wrapper for the clojure language focusing on how components change. This means in practice that things that normally wouldn't be changed, or is impossible to change in a convenient way, now is easily changeable and hopefully in a more functional way.
Consider the following example (from Hafni.test.swing.action/button-test2):
(frame :content (comp-and-events (button :name "*") :act (flow (output-arr this :name) >>> (arr #(str % "*")) >>> (input-arr this :name))) :size 200 200 :dont_exit_on_close)
This creates a frame (a window if you so will), with a button as content, size 200x200 and which doesn't close when the frame is closed (useful when working in the repl). It is likely that the code
(comp-and-events (button :name "*") :act (flow (output-arr this :name) >>> (arr #(str % "*")) >>> (input-arr this :name)))
will look very wierd if you haven't read the wiki. That is OK, we will now in a simple (and incomplete) way walk through this code. We first create a button with the text "*".
(button :name "*")
Then, when the button is pressed, the buttons text is extracted, another "*" is added to the end of that text, and set as the current text of the button.
(flow (output-arr this :name) >>> (arr #(str % "*")) >>> (input-arr this :name)))
Thus, the text of the button changes in the following way:
"*" "**" "***" "****"
To accomplish this, Hafni uses the datatypes Event and Arrow which are both explained in the wiki.Wiki/usage
Add [hafni "1.0.2-SNAPSHOT"] as a dependency in leiningen.
To the left is the java class or "functionality", to the right is the function used.
AbstractAction action ButtonGroup button-group JButton button JCheckBox check-box JCheckBoxMenuItem check-box-menu-item JMenuItem menu-item JRadioButton radio-button JRadioButtonMenuItem radio-button-menu-item JToggleButton toggle-button
JComboBox combo-box JList jlist JSpinner spinner JTabbedPane tabbed-pane
JFileChooser/showOpenDialog open-file JFileChooser/showSaveDialog save-file JOptionPane/showMessageDialog error-message info-message message plain-message warning-message JOptionPane/showInputDialog adv-input-dialog text-input-dialog
BorderLayout border-layout BoxLayout box-layout CardLayout card-layout FlowLayout flow-layout
JMenu menu JMenuBar menu-bar JToolBar tool-bar
JTable table table-model
JPasswordField password-field JTextArea text-area JTextField text-field JTextPane text-pane
File file *path-separator* Font font *available-fonts* Color color
JFrame frame JIcon icon JLabel label JProgressBar progress-bar JScrollPane scroll-pane
Copyright (c) 2011 Jonathan Fischer Friberg
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