MATLAB does not support syntax which directly index the function call return value, like "p2r([x y])(:,1)". It is recommended that you use temporary intermediate variables for indexing in a function declaration, rather than using anonymous function for 'p22r'.
As an alternative, however, you could use workaround with some limitations on the result. For example, if you need to return a value at the particular index (1,1) of 'p2r([x y])', you can use getfield or subsref functions as
p22r = @(x,y) getfield(p2r([x y]),{1,1});
or
p22r = @(x,y) subsref(p2r([x y]), struct('type', '()', 'subs', {{1, 1}}));
