selpath = hou.hscriptExpression('mousepath()').split('.')[-1]
voppath = '/'.join( selpath.split('/')[:-1] )
node = hou.node(voppath)

retval, aname = hou.ui.readInput("Attribute Name", buttons=('OK',))

if retval != -1:
    add = node.createNode('addattrib')
    add.setName("add_%s"%aname)
    add.parm('attrib').set(aname)
    add.parm('localvar').set(aname.upper())

    if aname == 'orient':
        add.parm('typemodifier').set('quaternion')