Declaration attributes (experimental)

Experimental syntax allows setting attributes on a WDL declaration. The semantics are defined by the runtime engine. For example, the diff task sets the streaming attribute on its two input files. This is interpreted by dxWDL to mean that A and B should not be downloaded, but streamed directly from the cloud.

task diff {
    File a { stream: true}
    File b { stream: true}

    runtime {
        docker: "ubuntu:16.04"
    }
    command {
        diff ${a} ${b} | wc -l
    }
    output {
        Int result = read_int(stdout())
    }
}