Modifying the Bibtex style file to get reference in a different form

Question

I am trying to modify a certain .bst file. At the moment I am able to hack the file to get the following reference output for an inbook entry:

Jones, W.P. 1994. Turbulence modelling and numerical solution methods for variable density and combustion flows, Turbulent Reacting Flows. In, Libby, P.A. and Williams, F.A., (Eds.). Academic Press, London, UK. pp. 309-374.

The only problem I have is that if you look above, there is a comma after the word 'In'. I know that this is because I tried to included the word 'In' in the .bst file. Does anyone know how to do this properly? Here is the bit of code where I modified to get 'In'.

FUNCTION {format.editors}
{ editor empty$
     { "" }
     {
       add.period$ " In" * editor format.names
       editor num.names$ #1 >
         { ", " * bbl.editors * }
         { ", " * bbl.editor * }
       if$
     }
   if$
}

And this is the code for the inbook entry

FUNCTION {inbook}
{ output.bibitem
  format.authors output.nonnull
  new.block
  format.date "year" output.check
  new.sentence
  format.chapter.pages "chapter and pages" output.check
  format.btitle "title" output.check
  crossref missing$
    { format.editors output
      new.block
      format.publisher
      new.sentence
    }
    { format.chapter.pages "chapter and pages" output.check
      new.block
      format.book.crossref output.nonnull
    }
  if$
  format.edition output
  new.sentence
  format.pages output
  new.block
  note output
  fin.entry
}

Answer 1

If I've understood right you want to remove comma between "In" and "Libby":

Jones, W.P. 1994. Turbulence modelling and numerical solution methods for variable density and combustion flows, Turbulent Reacting Flows. In Libby, P.A. and Williams, F.A., (Eds.). Academic Press, London, UK. pp. 309-374.

If so, here is correct using of operator *

FUNCTION {format.editors}
{ editor empty$
     { "" }
     {
       add.period$ " In " editor format.names *
       editor num.names$ #1 >
         { ", " * bbl.editors * }
         { ", " * bbl.editor * }
       if$
     }
   if$
}

Also, space is added after string " In".

The explanation of stack: in expression

" In" * editor format.names

operator * concatenates editor and " In" and then resulting string is parsed by format.names, which puts extra comma. In expression

" In " editor format.names *

operator * concatenates result of command editor format.names and " In ".