The calli:sparql step produces application/sparql-results+xml from RDF data.

<p:declare-step type="calli:sparql">
    <p:input port="source" sequence="true" primary="true" />
    <p:input port="query" sequence="true" />
    <p:input port="parameters" kind="parameter" primary="true"/>
    <p:option name="output-base-uri" />
    <p:option name="endpoint" />
    <p:output port="result" sequence="true" />

The RDF data can be provided in the source port as RDF/XML or with the provided SPARQL endpoint.

The SELECT parameters are populated in the query before evaluating the query against the data source.