namespace SampleFormulaPlugin
{
    public class CustomFormulas : ActuIT.Futurama.IoCInterfaces.IExternalFormulaLibrary
    {
        
        public XDocument GetFormulasDocument()
        {
            Stream formulaxml = Assembly.GetExecutingAssembly().GetManifestResourceStream("SampleFormulaPlugin.CustomFormulas.xml");
            return System.Xml.Linq.XDocument.Load(formulaxml);
        }
        public string GetLibraryName()
        {
            return "Various custom formulas";
        }

        public static int SampleCustomFormula(int input)
        {
            return input * 17 + 5;
        }
    }
}

<!--?xml version="1.0" encoding="utf-8"?-->
<formulalibrary version="4.1.2">
	<!-- the language information in a plugin is not used -->
	<languages>
		<language id="NL" name="">
		</language>
	</languages>
	<categories>
		<category id="1" order="1">
			<language id="">
				<name>SamplePlugin:Custom</name>
			</language>
		</category>
	</categories>
	<!-- you can define multiple formulas-->
	<formulas>
		<!-- the id's should start with 1
    method should be the method name as defined in the class
    class is the name of the class in the plugin
    type is the return type. The allowed types are System.Int32, System.Double, System.String, System.Boolean, System.DateTime 
    -->
		<formula id="1" method="SampleCustomFormula" class="SampleFormulaPlugin.CustomFormulas" type="System.Int32" categoryid="1">
			<language id="">
				<!-- the name of the formula that as it appears in the editor-->
				<name>SampleCustomFormula</name>
				<!-- the description of the formula as it appears in the editor-->
				<description>Determines the value of some business rule</description>
			</language>
			<parameter type="System.Int32" position="1" isarray="false">
				<language id="">
					<!-- the name of the parameter that is shown in the editor-->
					<name>Input</name>
					<!-- the description of the parameter that is shown in the editor-->
					<description>The input for the business rule</description>
				</language>
			</parameter>
		</formula>
		<!-- you can also add formulas that are defined in the .Net classes by Microsoft -->
		<formula id="2" method="Sin" class="System.Math" type="System.Double" categoryid="1">
			<language id="">
				<name>Sinus</name>
				<description>Determines the sinus for an angle</description>
			</language>
			<parameter type="System.Double" position="1" isarray="false">
				<language id="">
					<name>Angle</name>
					<description>The angle in radians for which you want to calculate the sinus</description>
				</language>
			</parameter>
		</formula>
	</formulas>
</formulalibrary>