And Now for XAML Completely Different

<Main xmlns="clr-namespace:MarkupScript;assembly=MarkupScript">
  <!-- 
    Define some arguments to demonstrate automated help message. 
    If you call this without any arguments you will see a simple help screen. 
    You may also use -? or -help to show the help screen.
  -->
  <Main.ArgumentDefinitions>
    <ArgumentDefinitions>
      <!-- 
        Sequential arguments are strings on the command line, usually file names. 
        The order of sequential arguments on the commmand line is important. 
      -->
      <SequentialArgument Name="FirstArgument" Description="You must enter at least one argument"/>
      <!-- Sequential arguments are mandtory by default, we must explicitly declare them optional -->
      <SequentialArgument Name="SecondArgument" Description="You may enter a second argument" IsOptional="True"/>
      <!-- 
        Switches are preceeded by "-" or "/". Since they have a name, the order on the command line is not important.
        Switches are optional by default, so we must explicitly declare mandatory switches as not optional.
        If the switch can be assigned a value (like "/<Switch>=<Value>) we must set the HasValue attribute to True.
      -->
      <SwitchArgument Name="MandatorySwitch" Description="You must enter this switch with a value!" HasValue="True" IsOptional="False"/>
      <SwitchArgument Name="OptionalSwitch" Description="You may add this optional switch"/>
    </ArgumentDefinitions>
  </Main.ArgumentDefinitions>
  
  <!-- Define some variables by setting the variables property. -->
  <Main.Variables>
    <Variables>
      <!-- Uninitialized variable. -->
      <Variable Name="UserInput"/>
      <!-- Variable initialized with boolean value. -->
      <Variable Name="Success" Value="True"/>
      <!-- Variable initialized with number value. -->
      <Variable Name="Number" Value="3"/>
      <!-- Expression macro, the expression will be evaluated every time the expression is used. -->
      <Expression Name="SampleExpression" Value="{NotEqual Left={Get UserInput}, Right={Get Number}}"/>
      <!-- Variable containing an array with three values. -->
      <Variable Name="AnArray">
        <Variable.Value>
          <Array>
            <Variable Name="ItemA" Value="_a_"/>
            <Variable Name="ItemB" Value="_b_"/>
            <Variable Name="ItemC" Value="_c_"/>
          </Array>
        </Variable.Value>
      </Variable>
    </Variables>
  </Main.Variables>

  <!-- Define some functions -->
  <Main.Functions>
    <Functions>
      <!-- Define a sample function with two arguments, 'Argument' and 'AnotherArgument'; AnotherArgument is optional -->
      <Function Name="TestFunction">
        <!-- Output some text -->
        <Echo Text="Inside function TestFunction"/>
        <!-- Output value of Argument. Use the Get expression to access the Argument variable. -->
        <Echo Text="{Get Argument}"/>
        <!-- Test the AnotherArgument value. The variable is optional, if it's missing it will evaluate to false. -->
        <If Condition="{Get AnotherArgument, Optional=True}">
          <!-- Output some text -->
          <Echo Text="AnotherArgument is True. Exit function"/>
          <!-- Return the value 1 -->
          <Return Value="1"/>
        </If>
        <!-- Output the global variable Number -->
        <Echo Text="{Get Number}"/>
      </Function>
    </Functions>
  </Main.Functions>

  <!-- Main program starts here -->

  <Echo Text="Sample usage of Get Set Input and Echo"/>

  <!-- Set the variable 'UserInput'. Use the result of the Input expression as the value -->
  <Set Variable="UserInput" Value="{Input Prompt='Enter some text'}"/>
  <!-- Output some text -->
  <Echo Text="Your input:"/>
  <!-- Output the value of variable UserInput -->
  <Echo Text="{Get UserInput}"/>

  <Echo Text="Sample usage of expression and condition"/>
  <If Condition="{Get SampleExpression}">
    <Echo Text="You did not enter 3"/>
    <If.Else>
      <Echo Text="Thanks for 3"/>
    </If.Else>
  </If>

  <Echo Text="Sample usage of ForEach loop"/>

  <!-- A string is an array of characters, so we can loop over them -->
  <ForEach Variable="loop" In="abcde">
    <!-- loop is the local loop variable -->
    <Echo Text="{Get loop}"/>
  </ForEach>

  <!-- Now loop over the array members of the variable AnArray -->
  <ForEach Variable="item" In="{Get AnArray}">
    <!-- item is the local loop variable -->
    <Echo Text="{Get item}"/>
  </ForEach>

  <Echo Text="Access array member by index"/>
  <Echo Text="{Get AnArray, Index=2}"/>

  <Echo Text="Access array member by member name"/>
  <Echo Text="{Get AnArray, Member=ItemB}"/>

  <Echo Text="Sample usage of Switch statement and binary expressions"/>
  <Switch>
    <!-- The first case where condition evaluates to true will be executed -->
    <Case Condition="{Equal Left='Test', Right={Get UserInput}}">
      <Echo Text="Your input was Test."/>
    </Case>
    <Case>
      <Echo Text="This switch will never be called. Empty condition is always false."/>
    </Case>
    <Case Condition="{GreaterThan Left={Get UserInput}, Right=5}">
      <Echo Text="You typed a number greater than 5."/>
    </Case>
    <!-- If no case matches, default will be called -->
    <Switch.Default>
      <!-- Default expects exactly one statement. Use the Scope statement to add more than one. -->
      <Scope>
        <Echo Text="You typed something else."/>
        <Echo Text=";-("/>
      </Scope>
    </Switch.Default>
  </Switch>

  <Echo Text="Sample usage of Scope and local variables"/>
  <Scope>
    <Scope.Variables>
      <Variables>
        <!-- Use a variable Number, this already exists in Main -->
        <Variable Name="Number" Value="42"/>
      </Variables>
    </Scope.Variables>
    <Echo Text="Output local variable Number"/>
    <Echo Text="{Get Number}"/>
    <Echo Text="Change local variable Number"/>
    <Set Variable="Number" Value="99"/>
    <Echo Text="Output local variable Number"/>
    <Echo Text="{Get Number}"/>
    <Echo Text="Output global variable UserInput inside scope"/>
    <Echo Text="{Get UserInput}"/>
  </Scope>
  <Echo Text="Output global variable Number"/>
  <Echo Text="{Get Number}"/>

  <Echo Text="Sample usage of function calls"/>

  <!-- Call test function with one argument -->
  <Call Function="TestFunction">
    <Argument Name="Argument" Value="-argument1-"/>
  </Call>

  <!-- Call test function with two arguments -->
  <Call Function="TestFunction">
    <Argument Name="AnotherArgument" Value="True"/>
    <Argument Name="Argument" Value="-argument1-"/>
  </Call>

  <!-- Call test function and assing function result to variable number -->
  <Set Variable="Number">
    <Set.Value>
      <Call Function="TestFunction">
        <Argument Name="AnotherArgument" Value="True"/>
        <Argument Name="Argument" Value="-argument1-"/>
      </Call>
    </Set.Value>
  </Set>

  <Echo Text="Output global variable Number after call of function"/>
  <Echo Text="{Get Number}"/>

  <Pause Prompt="Press any key"/>

</Main>