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On-line Crystallographic Information Files (CIFs)

CIFs are now being published on line in the IUCr journals (see for example Acta Cryst. Volume C53. part 6 (June 1997).
Currently these CIF files are transmitted with a MIME type of "text/plain", but moves are afoot to change this and add a new MIME type: "chemical/x-cif"

Viewing CIF files

The following two files provide a means of adding CIF viewing to your Netscape browser. Provided you have Cif-browsing software available - such as Xtal_GX for example. For this solution to work, you also need the Tcl/Tk toolkits installed

cif_filter.tcl ... a Tcl/Tk script initiated by Netscape
filesel.tcl ... an auxilliary Tcl/Tk file required by cif_filter.tcl

#  (1) copy the cif_filter.tcl  to     $HOME/.netscape/cif_filter.tcl
#  (2) make scipt executable: chmod +x $HOME/.netscape/cif_filter.tcl
#  (3) copy     filesel.tcl     to     $HOME/.netscape/filesel.tcl

Enabling your Netscape browser to use helper applications

#  (4) start netscape
#      click to "Options/General_Preferences/Helpers/New"
#      so as to add another MIME Configuration type by entering....
#
#          "Description" as   Crystallographic Information file
#          "Type"        as   text/plain    
Warning : text/plain is the buggy bit. Having done this you may find that Netscape fires up cif_filter.tcl when you least expect it! (hopefully you will find this bearable until the new MIME type is officially instigated)
#          "Suffix"      as   cif
#
#       and in "Handle By" click "Application" and then "Browse"
#           in the Directories list  click  "/.netscape"
#           in the Files       list  click  "cif_filter.tcl"
#           in the Selection window  append "  %s"       <<<<< Important
#
#       and then hit "OK" "OK"  on successive windows.

Configuring cif_filter.tcl to access your CIF viewing software

This is the tricky part.

cif_filter.tcl works by filtering the input CIF to obtain a list of data_blocks. It highlights those data blocks in the text and when they are selected (by clicking with a mouse button) it copies the current version of the loaded cif to a temporary file, the name of which is passed, along with a block number to an external CIF viewer. It spawns an external command of the form:

         command  -b number  filename  
Your job is to make sure that the "command" is correct.
It is defined internally in cif_filter.tcl on the line
   set defaultCommand   "$env(HOME)/.netscape/cif_xtal" 
(supposedly there is on line editing of this command but that is untested)

Using cif_filter.tcl with Xtal or Xtal_GX

If you are viewing CIFs with Xtal or Xtal_GX on a UNIX workstation, you will also need to obtain the following Bourne shell CIF preprocessor: cif_xtal

#  (1) copy the cif_xtal  to     $HOME/.netscape/cif_xtal
#  (2) make scipt executable: chmod +x $HOME/.netscape/cif_xtal

You will need to modify several vaiables in this script file for local Xtal installations. They are contained near the beginning of cif_xtal

#########################################################################
#       variables which will need to be set for local conditions
#
PATH=/util/Xtal:$PATH      # make sure the PATH to the XTAL directory is known
EXECUTABLE=xtal_3.5        # the name of the executable
#
# Define environment variable pointing to directory of Xtal auxilliary files
XTALHOME=/util/Xtal/aux/   # trailing slash required!!
#
# define a directory to run xtal and where all scratch (etc) files appear
LOCALDIR=$HOME/.netscape/xtal
#########################################################################

(Hopefully a future version of this script, written in tcl/tk will permit online editing of the XTAL commands to be executed, but this version doesn't)

Good Luck!
Mail any feedback to xtal@crystal.uwa.edu.au