Function: _'_
Section: symbolic_operators
C-Name: derivn
Prototype: GLDn
Help: x': derivative of x with respect to the main variable.
Description:
 (gen,1):gen                      deriv($1, -1)

 (FpX,1):FpX                      FpX_deriv($1, p)
 (FqX,1):FqX                      FqX_deriv($1, T, p)

Function: _'
Section: symbolic_operators
C-Name: deriv
Prototype: GDn
Help: x': derivative of x with respect to the main variable.
