# Segnale di protezione automatico ad una luce
# Aspetti consentiti:
# R      via impedita
# G o V  via libera
#
Aspect: red
   IconE: r_PE.xpm
   IconW: r_PW.xpm
   IconN: r_PN.xpm
   IconS: r_PS.xpm
   Action: stop

Aspect: yellow
   IconE: y_PE.xpm
   IconW: y_PW.xpm
   IconN: y_PN.xpm
   IconS: y_PS.xpm
   Action: proceed

Aspect: green
   IconE: g_PE.xpm
   IconW: g_PW.xpm
   IconN: g_PN.xpm
   IconS: g_PS.xpm
   Action: proceed

OnInit:
   .aspect = red
   .fleeted = 1
end

# user cleared the signal
# and the path ahead is not occupied by a train

OnCleared:
   if .aspect = red
      if next.aspect = red
         .aspect = yellow
      else
         .aspect = green
      end
   end
end

# another signal changed aspect,
# see if we need to change our aspect as well

OnUpdate:
    if .aspect = red
      return
    end
    if next.aspect = red
       .aspect = yellow
    else
       .aspect = green
    end
end