Htk.ColumnSpin = new Class
({
	Extends: Htk.Column
	,Tag: 'htk-column-spin'
	,Properties:
	{
		/**
		 * The text to append to the number.
		 **/
		unit:
		{
			type: String
			,value: null
		},
		/**
		 * The number of decimal places to display.
		 **/
		digits: {
			type: Number
			,value: 0
		}
	}

	,render: function (tr)
	{
		var td = this.parent (tr);
		td.style.textAlign = 'right';
		
		var valueString = null;
		
		if (this.value !== null && this.value !== undefined)
			valueString = new Number (this.value).toFixed (this.digits);

		if (this.editable)
		{
			var entry = document.createElement ('input');
			entry.type = 'text';
			entry.className = 'cell-spin';
			entry.addEventListener ('change', this.inputChanged.bind (this, tr, entry));
			td.appendChild (entry);
			
			if (valueString)
				entry.value = valueString;
		}
		else if (valueString)
		{
			if (this.unit)
				valueString = valueString +' '+ this.unit;
		
			var text = document.createTextNode (valueString);
			td.appendChild (text);
		}

		return td;
	}
	
	,inputChanged: function (tr, entry)
	{
		this.changed (tr, parseInt (entry.value));
	}
});