# Using Scripting Language to Change/Build Formulas

WinTrend provide a flexible way to change exising or embed your own formulas. You can bundle all you formulas to a dll file, put it to the plugins subfolder, then it will be loaded automatically when main program start.

Open Formula Editor using **Tools >> Formula Editor** menu item. The following dialog will appear on your desktop(Figure 1).

**Figure 1**

Expand the left tree to find the MACD formula (Figure 2).

**Figure 2**

There are three parameters in this formula, LONG,SHORT and M. These parameters are referenced by the formula program.
In the code text box shows following formula:

*
DIFF : EMA(CLOSE,SHORT) - EMA(CLOSE,LONG);
DEA : EMA(DIFF,M);
MACD : 2*(DIFF-DEA), COLORSTICK;
*

This means the formula will show three lines on the chart :

**DIFF**,

**DEA**and

**MACD**.

Let's see the first line :

*DIFF : EMA(CLOSE,SHORT) - EMA(CLOSE,LONG);*

This line means that the exponental moving average of the last

**LONG**days closes will be subtracted from the exponental moving average of the last

**SHORT**days closes. The

**LONG**and

**SHORT**was specified in the parameter area (Figure 3).

The second line means that the exponental moving average of the last "

**M**" days of

**DIFF**.

**DIFF**is the value returned by the first line. The third line means that first line subtract the second line, the result multiply by 2. and show this line in a style of

**COLORSTICK**.

**Figure 3**

Close **Formula Editor** and add **MACD** formula to chart. You can see how the **MACD** formula is drawn in the chart (Figure 4).

**Figure 4**

Let's modify the **MACD** formula, and see what happens.

Add two lines in the code text box:

*
0.25;
TRIMA:MA(DEA,M2);
*

Press

**F9**to compile it. The editor shows an error

*"The name M2 does not exist"*. This is because we did not define this parameter (Figure 5).

**Figure 5**

Right click **MACD** in the tree, add the parameter **M2**.(Figure 6-7)

**Figure 6**

**Figure 7**

Press F9 to Compile.

This time we get the OK! message in the editor (Figure 8).

**Figure 8**

Close **Formula Editor** and confirm the changes you have made (Figure 9).

**Figure 9**

Let's return back to WinTrend and see what are the differences. You will see two extra lines shown in the chart (Figure 10).

**Figure 10**