Run selected text if available instead of complete exercise code

[gadenbuie]

Fixes #512.

A note about implementation: I used editor.getSelectedText() to get the selected text in the editor. We're currently using editor.getSession().getValue() for the full code in the editor. I'm fairly certain that editor.getSession() is not required — I think editor.getValue() will return the same thing — and if it is required then we would need to follow a much more complicated way of getting the selected text.

TODO:

• NEWS item

[schloerke]

https://stackoverflow.com/a/23996816/591574 suggests something like:

editor.getSession().getTextRange(editor.getSession().selection.getRange())

We do not have multi select mode enabled, so editor.getSelectedText() eventually calls:

 this.session.getTextRange(this.getSelectionRange());

... which is equivalent to editor.getSession().getTextRange(editor.getSession().selection.getRange())

---

tl/dr; Use editor.getSelectedText()

[schloerke]

I'm fairly certain that editor.getSession() is not required — I think editor.getValue() will return the same thing

Correct. editor.getValue() calls this.session.getValue(). So they are equivalent.

However, editor.setValue(txt) does an extra text selection step after calling this.session.setValue(txt). From the code, editor.setValue(txt) is not the same as editor.getSession().setValue(txt).

editor.setValue:

    this.setValue = functioned(val, cursorPos) {
        this.session.doc.setValue(val);

        if (!cursorPos)
            this.selectAll();
        else if (cursorPos == 1)
            this.navigateFileEnd();
        else if (cursorPos == -1)
            this.navigateFileStart();

        return val;
    };

editor.getSession().setValue:

    this.setValue = function(text) {
        this.doc.setValue(text);
        this.selection.moveTo(0, 0);

        this.$resetRowCache(0);
        this.$deltas = [];
        this.$deltasDoc = [];
        this.$deltasFold = [];
        this.setUndoManager(this.$undoManager);
        this.getUndoManager().reset();
    };

[schloerke]

Nice!