We have seen how scripting basically works for indentation. It’s also possible to register commandline functions (The command line is bound to F7 by default, or invoke View > Switch to Command Line). We will consider a small example again: sort the selected text.

/* kate-script
 * name: unused
 * author: foo bar
 * license: LGPL
 * version: 1
 * kate-version: 3.0
 * functions: sorter
 */

function sorter ()
{
    if (view.hasSelection()) {
        var start = view.startOfSelection().line;
        var end = view.endOfSelection().line;

        var text = document.textRange(start, 0, end, document.lineLength(end));

        var lines = text.split(“\n”);
        lines.sort();
        text = lines.join(“\n”);

        view.clearSelection();

        document.editBegin();
        document.removeText(start, 0, end, document.lineLength(end));
        document.insertText(start, 0, text);
        document.editEnd();
    }
}

The header line functions: sorter makes Kate Part aware of the function in the script. A list of functions is supported, separated by white spaces. You can use the function by typing ‘sorter’ in the commandline.
Some todo items:

• provide better JavaScript API. For example: document.textRange() takes 4 parameters. It would be more elegant to take one range or two cursors, just like we do in the KTextEditor interfaces in kdelibs/interfaces/ktexteditor
• make is possible to bind scripts to shortcuts. This could be done by e.g. binding commandline functions to shortcuts or implementing a vim-like command-mode in Kate’s commandline. How to configure the shortcuts is unclear, though.
• then, think about replacing the C++ implementations of ‘uppercase’, ‘lowercase’, ‘capitalize’ etc. with scripts
• things I forgot…

If you are interested subscribe to kwrite-devel@kde.org and contribute 🙂 We also need indentation scripts, of course!

My last blog was about the theory of how indentation works by using javascripts. Now we will look at a concrete example: a LISP-style indenter. (LISP indentation is easy, that’s why it’s a good example).
The rules:

• comments starting with ;;; always have indentation 0
• comments starting with ;; should be aligned with the next line
• comments starting with ; should only appear behind code, so they are simply ignored
• every ‘(‘ indents and every ‘)’ unindents

lisp.js looks like this:

/** kate-script
* name: LISP
* license: LGPL
* author: foo bar
* version: 1
* kate-version: 3.0
* type: indentation
*/
// indent should be called when ; is pressed
triggerCharacters = “;”;
function indent(line, indentWidth, ch)
{
// special rules: ;;; -> indent 0
//                ;;  -> align with next line, if possible
//                ;   -> usually on the same line as code -> ignore
textLine = document.line(line);
if (textLine.search(/^\s*;;;/) != -1) {
return 0;
} else if (textLine.search(/^\s*;;/) != -1) {
// try to align with the next line
nextLine = document.nextNonEmptyLine(line + 1);
if (nextLine != -1) {
return document.firstVirtualColumn(nextLine);
}
}

cursor = document.anchor(line, 0, ‘(‘);
if (cursor) {
return document.toVirtualColumn(cursor.line, cursor.column) + indentWidth;
} else {
return 0;
}
}

The result:

;;; fib : number -> number
(define (fib n)
(if (< n 2)
1
(+ (fib (- n 1)) (fib (- n 2)))))

As this indenter is scripted, everybody can adapt the style to the own needs.