gs.nls

to export-gs
  gs-hide
  ifelse any? T-visible
  [
    let status gs:add-singlegraph "View"
    set status gs:start-viewer gs:current-graph-name
    set status gs:add-all-nodes T-visible
    set status gs:add-all-edges links with [not hidden?]
  ]
  [
    user-message "There is nothing to show"
  ]
end

to gs-hide
  foreach gs:viewers-names
  [ let status gs:close-viewer ?
    
    ifelse status
    [ output-print (word "Viewer " ? " closed") ]
    [ output-print (word "Problem with the viewer " ?) ] ]
  
  foreach gs:graphs-names
  [ let status gs:clear-graph ?
    
    ifelse status
    [ output-print (word "Graph " ? " cleared") ]
    [ output-print (word " Problem with the graph " ?) ] ]
end