Add order of nodes

I need to add a position attribute to each node of a certain type,
because each node represents a set of subsequent text blocks.

We assure that the node are writen to the XML in the right order. It
looks like this

<doc>
	<fragment>...</fragment>
	<fragment>...</fragment>
	<fragment>...</fragment>
	...
</doc>

I need a <xsl:template match="fragment"> that produces this output:

<doc>
	<fragment pos="1">...</fragment>
	<fragment pos="2">...</fragment>
	<fragment pos="3">...</fragment>
	...
</doc>

Can I use position() for that.

Help is much appreciated.

Robert