Rift Source + PEG-generated AST XML

hello.rift

hello {
  // Create our simple function
  sum(a, b) => a + b
  // Create a function to defer the computation
  deferredSum(a, b) => => sum(a, b)
  // Bind the evaluation of the computation in "myThread" to variable "a"	
  a := deferredSum(10, 20) @ myThread
  // Print out the value once it's available    
  print(a)
}

hello.rift_ast.xml

<?xml version="1.0" ?>
<Source>
  <Rift>
    <Identifier>hello</Identifier>
    <Block>
      <Expression>
        <FunctionDef>
          <Identifier>sum</Identifier>
          <Tuple>
            <Identifier>a</Identifier>
            <Identifier>b</Identifier>
          </Tuple>
          <ReturnValue>
            <Expression>
              <Operation>
                <Identifier>a</Identifier>
                <Operator>+</Operator>
                <Identifier>b</Identifier>
              </Operation>
            </Expression>
          </ReturnValue>
        </FunctionDef>
      </Expression>
      <Expression>
        <FunctionDef>
          <Identifier>deferredSum</Identifier>
          <Tuple>
            <Identifier>a</Identifier>
            <Identifier>b</Identifier>
          </Tuple>
          <ReturnValue>
            <ReturnValue>
              <Expression>
                <FunctionCall>
                  <Identifier>sum</Identifier>
                  <Tuple>
                    <Expression>
                      <Identifier>a</Identifier>
                    </Expression>
                    <Expression>
                      <Identifier>b</Identifier>
                    </Expression>
                  </Tuple>
                </FunctionCall>
              </Expression>
            </ReturnValue>
          </ReturnValue>
        </FunctionDef>
      </Expression>
      <Expression>
        <Operation>
          <Identifier>a</Identifier>
          <Operator>:=</Operator>
          <Aside>
            <FunctionCall>
              <Identifier>deferredSum</Identifier>
              <Tuple>
                <NumericLiteral>10</NumericLiteral>
                <NumericLiteral>20</NumericLiteral>
              </Tuple>
            </FunctionCall>
            <Expression>
              <Identifier>myThread</Identifier>
            </Expression>
          </Aside>
        </Operation>
      </Expression>
      <Expression>
        <FunctionCall>
          <Identifier>print</Identifier>
          <Tuple>
            <Expression>
              <Identifier>a</Identifier>
            </Expression>
          </Tuple>
        </FunctionCall>
      </Expression>
    </Block>
  </Rift>
</Source>