I want to query a maya nurbs curve for its basis / interpolation style but 
nothing in the api looks like it
http://download.autodesk.com/us/may...urbs_curve.html 
<http://download.autodesk.com/us/maya/2009help/API/class_m_fn_nurbs_curve.html>I
 
seem unable to find anything about it
In the end I need to match it up with the renderman ones:

A Bezier basis generates a 3D curve that passes through every third control 
vertex. The remaining control vertex positions are used to 
determine the incoming and outgoing tangent of the curve of the adjacent
vertex that the curve does pass through. When using a Bezier basis with
curves that contain multiple segments (that is, more than 4 control 
points), some care should be taken to ensure that incoming and outcoming
tangents line up at vertices that are on the rendered curve, or there 
will be a discontinuity in the smoothness of the curve where it suddenly
changes direction.

B-Spline - While a B-Spline basis function can be somewhat less intuitive 
to use in that it generates a curve that typically only 
approximately comes close to passing through the given control vertices,
an advantage is that this basis function tends to yield very smooth 
curves. Discontinuities in the smoothness of the curve are possible if 
multiple control vertices are repeated consecutively.

Catmull-Rom - This basis function generates a curve that is guaranteed to 
pass through every interior, non-endpoint control vertex, 
and it tends to generate smooth curves, although there can sometimes be 
unexpected "wobbles" in areas of high curvature with this basis function
choice (see images below for an example). Using a B-Spline basis 
instead can smooth out the wobbles, although a B-Spline basis typically 
produces a curve that does not pass through the control vertices 
exactly, unlike the Catmull-Rom basis (for non-endpoint control 
vertices).

Hermite - The Hermite basis function generates a curve that passes through 
every other control vertex; the remaining control "vertices" are
actually vectors that determine the tangent of the curve. The length of
the tangent vectors determines the amount of curvature; longer tangent 
vectors yield more curvature along the spline than shorter vectors. A 
Hermite basis function tends to produce smooth curves, although using a 
B-Spline basis can often yield qualitatively a more "natural" or uniform
smoothness along the curve with comparatively less specification 
effort.

Linear - Specifying linear curves yields straight line segments, which can 
result in gaps or other geometric artifacts when close to the 
camera (this may be acceptable for distant and/or very thin curves).

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