A node in a dynamic dataflow graph that receives values of type 'b and * produces values of type 'a.

An uninhabited type used in the definition of create_source and * from_pipe. This is the type of values that these nodes receive, thus they * cannot receive any values.

create init f creates an isolated node, initialized to hold init. * Use the attach function to connect the node to consumers and producers. * When any producer produces a value (of type 'b), the function f is * applied to latest values of each produced to calculate the new value of * this node. The new value is sent to all the consumers of this node.

create_source init creates an isolated node initialized to hold init. * You must not create an edge to this node--it will signal an error if it * receive a value. But, you can update the value at the node using push.

push v src sets the value at src to v and propagates the update * through the dataflow graph.

attach src dst sends values from src to dst. Be careful not to * create a cyclc. If you do, an infinite loop will occur while propagating * values.

from_pipe init reader creates a node initialized to init that is * updated with values from reader. * * Note: You cannot create an edge to this node, but you can create an edge * from this node to another that accepts values of type 'a.

to_pipe src returns the current value of src and a pipe that carries * all future values of src.