1 ((function dFdx 2 (signature float 3 (parameters 4 (declare (in) float p)) 5 ((return (expression float dFdx (var_ref p))))) 6 7 (signature vec2 8 (parameters 9 (declare (in) vec2 p)) 10 ((return (expression vec2 dFdx (var_ref p))))) 11 12 (signature vec3 13 (parameters 14 (declare (in) vec3 p)) 15 ((return (expression vec3 dFdx (var_ref p))))) 16 17 (signature vec4 18 (parameters 19 (declare (in) vec4 p)) 20 ((return (expression vec4 dFdx (var_ref p))))) 21 )) 22