anchor.diff:    implicit none
     private 
     public :: protein_alphabet
  +  public :: nuc_acid_alphabet
     public :: fasta_read
     character(len=1) :: protein_alphabet(21) = &
          ['A','C','D','E','F','G','H','I','K',&
  
positive.code:     logical :: res
  
      res = .false.
      if (verify(string,nuc_acid_set) == 0) res = .true.
      
    end function is_nuc_acid
    
  
negative.code:     logical :: res
  
      res = .false.
      if (verify(trim(string),trim(protein_set)) == 0) res = .true.
      
    end function is_protein
  
  