Elementary Examples

Simple expression that computes 1 + 1.

Note that <add> uses floating point arithmetic by default, giving "2.0" as the result. However, when all operands are long values, it'd be better to explicitly instruct <add> to calculate integer operations by specifying the "datatype" attribute: <add datatype="long"> .

							
<expression xmlns="http://xmlmath.org/1.0">
  <add>
    <long value="1"/>
    <long value="1"/>
  </add>
</expression>
						

This example illustrates how xmlmath can manipulate strings. It shows the use of <strcat> to concatenate two or more strings and <string> to create a literal string.

							
<expression xmlns="http://xmlmath.org/1.0">
  <strcat>
    <string value="Hello"/>
    <string value=" "/>
    <string value="world."/>
  </strcat>
</expression>
						

The expression below shows how <substr> is used to select substrings. It transforms the string "unhappy" into "happy".
The operator <substr> takes three arguments: first a string and then two numerical (long) indices. The first marks the beginning index (inclusive), while the second marks the ending index (exclusive).

							
<expression xmlns="http://xmlmath.org/1.0">
  <substr>
    <string value="unhappy"/>
    <long value="2"/>
    <strlen>
      <string value="unhappy"/>
    </strlen>
  </substr>
</expression>
						

The example shows the use of lists in xmlmath. First a list is created using the <list> operator. This list is then fed to <sort> which sorts the elements in the list in ascending order.

The expression yields the following result: [-0.0, 0.0, 2.718281828459045, 3.0, 3.141592653589793, Infinity]

							
<expression xmlns="http://xmlmath.org/1.0">
  <sort>
    <list>
      <infinity/>
      <double value="0"/>
      <e/>
      <double value="-0"/>
      <pi/>
      <double value="3"/>
    </list>
  </sort>
</expression>