# overloading of open and close #
 
# rename the "official commands
rename open __open
rename close __close
# rename fconfigure __fconfigure
# rename file __file
 
# overloaded open which registers file and fid info
# for files
proc open { args } {
     if { [ llength $args ] == 1 } {
        set args [ lindex $args 0 ]
     }
     set fid [ eval __open $args ]
     set file [ lindex $args 0 ]
     lappend ::open_files_array(fid,$fid) $file
     lappend ::open_files_array(file,$file) $fid
     return $fid
}
 
# overloaded close which lets you close a file i.d.,
# a socket i.d., or all the file i.d.'s associated
# with a file name.
proc close { args } {
     
     if { [ llength $args ] == 1 } {
        set args [ lindex $args 0 ]
     }   
    
     foreach arg $args {
        set type [ list ]

        if { [ regexp {^(sock|file)\d+$} $arg -> type ] } {
           __close $arg
        }
        
        if { [ catch {
           switch -exact $type {
                 file {
                      set file [ managearray $arg [ fid2file $arg ] ]
                      }
                 sock {
                      }
              default {
                      set fids [ file2fid $arg ]
                      after 10 close $fids
                      }               
           }  
        } err ] } {
           return -code error "$arg not found"
        }
     }
     if { [ info exists file ] } {
        return $file
     }
}     
 
# proc file { args } {
# your code here!
# }

# proc fconfigure { args } {
# your code here!
# } 

# helper functions

# given a fid, return the filename
proc fid2file { fid } {
     return $::open_files_array(fid,$fid)
}

# given a filename return all open fids
proc file2fid { file } {
     return $::open_files_array(file,$file)
}

# manage the arrays
proc managearray { fid file } {
     unset ::open_files_array(fid,$fid)
     set i [ lsearch $::open_files_array(file,$file) $fid ]
     set ::open_files_array(file,$file) \
         [ lreplace $::open_files_array(file,$file) $i $i ]
     if { ! [ llength $::open_files_array(file,$file) ] } {
           unset ::open_files_array(file,$file)
        }
     return $file
}