[Rd] how to define method for "+" function in a new class

[james.foadi at diamond.ac.uk]

Dear R developers,
I have a new class, which I called "Molecule", and have tried to define =
a "+" operation for 2 objects of this class.
This is what I have written so far, although the method is not complete =
(I'm trying to look at it at intermediate stages):

setMethod(
          f=3D"+",
          signature(x=3D"Molecule",y=3D"Molecule"),
          definition=3Dfunction(x,y,...)
                     {
                      # Check both objects are correct
                      checkMolecule(x)
                      checkMolecule(y)

                      # Extract chains information
                      ch1 <- getMoleculeChains(x)
                      ch2 <- getMoleculeChains(y)
                      union_ch <- unique(c(ch1,ch2))
                      not_used <- .ALPHABET
                      for (i in seq(along =3D union_ch))
                      {
                       idx <- which(not_used !=3D union_ch[i])
                       if (length(idx) !=3D 0) not_used <- not_used[idx]
                      }

                      return(not_used)
                     }
         )


The definition of class Molecule is included earlier in the same file. =
When I source it, I get the following error message:

Error in match.call(fun, fcall) :=20
  unused argument(s) (x =3D "Molecule", y =3D "Molecule")


I can't see what's wrong in my method definition. Can anyone help me =
with this?

J

Dr James Foadi PhD
Membrane Protein Laboratory (MPL)
Diamond Light Source Ltd
Diamond House
Harewell Science and Innovation Campus
Chilton, Didcot
Oxfordshire OX11 0DE

Email    :  james.foadi at diamond.ac.uk
Alt Email:  j.foadi at imperial.ac.uk

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