[xsl] XPath 3.0 is a composable language ... what does that mean?

["Costello, Roger L." <costello@xxxxxxxxx>]

Hi Folks,

I read this in the XPath 3.0 specification:

    XPath 3.0 is a composable language

What does that mean?

I know what function composition is: two functions, f and g, can be composed:

     f . g

thus creating a new function that applies f after g.

Is there some relationship between "function composition" and  " XPath 3.0 is
a composable language"?

To give me an intuitive sense of what it means, would you please provide some
examples of composing parts of the XPath 3.0 language?

Thanks!

/Roger