tcl: dumping tablelist data

For the tablelist widget I created a function to dump the table content to a file

proc dumpTableListToFile { tree { file preview.txt } } { 
    set rowCount [$tree size]
    set file_writer [open $file  w+]
    for { set i 0 } { $i < $rowCount } { incr i } {
	set rowData [$tree get $i]
	puts $file_writer $rowData 
    }
    close $file_writer
}

parameters:

tree, is the table widget, file is the file name, optional.