diff --git a/src/net/mc_pandacraft/java/plugin/pandacraftutils/calculator/CalculatorManager.java b/src/net/mc_pandacraft/java/plugin/pandacraftutils/calculator/CalculatorManager.java
new file mode 100644
index 0000000..64e1bbf
--- /dev/null
+++ b/src/net/mc_pandacraft/java/plugin/pandacraftutils/calculator/CalculatorManager.java
@@ -0,0 +1,120 @@
+package net.mc_pandacraft.java.plugin.pandacraftutils.calculator;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import net.mc_pandacraft.java.plugin.pandacraftutils.PandacraftUtils;
+import net.mc_pandacraft.java.util.JArithmeticInterpreter;
+import net.mc_pandacraft.java.util.StringUtil;
+
+import org.bukkit.ChatColor;
+import org.bukkit.entity.Player;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.EventPriority;
+import org.bukkit.event.Listener;
+import org.bukkit.event.player.AsyncPlayerChatEvent;
+import org.bukkit.event.player.PlayerJoinEvent;
+import org.bukkit.event.player.PlayerQuitEvent;
+
+public class CalculatorManager implements Listener {
+	
+	private PandacraftUtils plugin;
+	
+	private Map<Player, List<HistoryElement>> history = new HashMap<Player, List<HistoryElement>>();
+	
+	
+	
+	public CalculatorManager(PandacraftUtils pl) {
+		plugin = pl;
+		
+		plugin.getServer().getPluginManager().registerEvents(this, plugin);
+		
+		// analyse des joueurs déjà en ligne (/reload)
+		for (Player p : plugin.getServer().getOnlinePlayers())
+			onPlayerJoin(new PlayerJoinEvent(p, ""));	// simule l'évènement d'arrivé d'un joueur, pour le rajouter
+	}
+	
+	
+	
+	
+	@EventHandler(priority=EventPriority.HIGHEST)
+	public void onAsyncPlayerChat(AsyncPlayerChatEvent event)
+	{
+		String message = event.getMessage();
+		if (!message.startsWith("="))
+			return;
+		
+		if (message.length() == 1)
+		{	// affichage de l'historique
+			event.getPlayer().sendMessage(ChatColor.GRAY+"Historique d'utilisation de la calculatrice");
+			int i = history.get(event.getPlayer()).size();
+			for(HistoryElement el : history.get(event.getPlayer()))
+			{
+				event.getPlayer().sendMessage(ChatColor.GRAY+"res"+i+ChatColor.RESET+"="+ChatColor.GRAY+el.value+ChatColor.RESET+"="+ChatColor.GRAY+el.expression);
+				i--;
+			}
+		}
+		else
+		{
+			try {
+				message = message.substring(1);
+				
+				// TODO prendre en compte les variables "resX"
+				
+				
+				
+				StringBuffer expression = new StringBuffer();
+				
+				HistoryElement calcul = new HistoryElement();
+				calcul.value = StringUtil.formatDouble(JArithmeticInterpreter.getResultFromExpression(message, expression));
+				calcul.expression = expression.toString();
+				
+				history.get(event.getPlayer()).add(calcul);
+				if (history.get(event.getPlayer()).size() > 5)
+					history.get(event.getPlayer()).remove(0);
+				
+				event.getPlayer().sendMessage("="+ChatColor.GRAY+calcul.value);
+			}
+			catch (IllegalArgumentException e) {
+				event.getPlayer().sendMessage(ChatColor.RED+e.getMessage());
+				
+			}
+			
+		}
+		
+		
+		
+		
+		event.setCancelled(true);
+	}
+	
+	
+
+	
+	
+	@EventHandler
+	public void onPlayerJoin(PlayerJoinEvent event)
+	{
+		history.put(event.getPlayer(), new ArrayList<HistoryElement>());
+	}
+	
+	
+	
+	@EventHandler
+	public void onPlayerQuit(PlayerQuitEvent event)
+	{
+		history.remove(event.getPlayer());
+	}
+	
+	
+	
+	private class HistoryElement
+	{
+		public String expression;
+		public String value;
+	}
+	
+	
+}
diff --git a/src/net/mc_pandacraft/java/plugin/pandacraftutils/chat_analyzer/ChatAnalysisManager.java b/src/net/mc_pandacraft/java/plugin/pandacraftutils/chat_analyzer/ChatAnalysisManager.java
index 965fdac..cc97af1 100644
--- a/src/net/mc_pandacraft/java/plugin/pandacraftutils/chat_analyzer/ChatAnalysisManager.java
+++ b/src/net/mc_pandacraft/java/plugin/pandacraftutils/chat_analyzer/ChatAnalysisManager.java
@@ -31,7 +31,7 @@ public class ChatAnalysisManager implements Listener {
 			onPlayerJoin(new PlayerJoinEvent(p, ""));	// simule l'évènement d'arrivé d'un joueur, pour le rajouter
 	}
 	
-	@EventHandler(priority=EventPriority.HIGHEST)
+	@EventHandler(priority=EventPriority.HIGH,ignoreCancelled=true)
 	public void onAsyncPlayerChat(AsyncPlayerChatEvent event)
 	{
 		try {
diff --git a/src/net/mc_pandacraft/java/util/JArithmeticInterpreter.java b/src/net/mc_pandacraft/java/util/JArithmeticInterpreter.java
index bc91dc9..a81f04e 100644
--- a/src/net/mc_pandacraft/java/util/JArithmeticInterpreter.java
+++ b/src/net/mc_pandacraft/java/util/JArithmeticInterpreter.java
@@ -449,21 +449,12 @@ public class JArithmeticInterpreter {
 	
 	//.................................................................................... Write_Tree
 	
-	public String writeTree() {
-		StringBuffer sb = new StringBuffer();
-		writeTree(sb);
-		return sb.toString();
-	}
-	
-	
-	
-	
 	private void writeTree(StringBuffer string) {
 		boolean parenthese=false;
 	
 		switch(mOperator) {
 			case 0:
-				string.append(mValue);
+				string.append(StringUtil.formatDouble(mValue));
 				break;
 			case 1:
 				fg.writeTree(string);
@@ -740,7 +731,7 @@ public class JArithmeticInterpreter {
 	}
 	
 	
-	public static double getResultFromExpression(String expr)
+	public static double getResultFromExpression(String expr, StringBuffer writeTree)
 	{
 		StringBuffer input = new StringBuffer(expr);
 
@@ -749,16 +740,29 @@ public class JArithmeticInterpreter {
 		if (jai==null)
 			throw new IllegalArgumentException("Le calcul passé en paramètre est invalide");
 		
+		if (writeTree != null)
+		{
+			writeTree.setLength(0);
+			jai.writeTree(writeTree);
+		}
+		
 		return jai.computeTree();
 	}
 	
-	/*
+	public static double getResultFromExpression(String expr)
+	{
+		return getResultFromExpression(expr, null);
+	}
+	
 	
 	public static void main(String args[]) {
 		
-		String disp_res = StringUtil.formatDouble(JArithmeticInterpreter.getResultFromExpression("1245.25*2"));
+		StringBuffer b = new StringBuffer(0);
+		
+		String disp_res = StringUtil.formatDouble(JArithmeticInterpreter.getResultFromExpression("1245.25*2", b));
 		
 		System.out.println(disp_res);
-	} //*/
+		System.out.println(b);
+	} // */
 	
 }