The do loop iterates over a set of things, navigating from the current element. For example one could query the relationships of an object like this:

do >relType
{/* Operations for relationships */ }

Note that do loops differ from foreach. Foreach will always look at the current graph, and can only iterate over objects, roles or relationships directly contained in that graph. Do and dowhile will look at the current element, and iterate over those instances of the specified type that are attached to the current element in the current context. For this reason, foreach will normally be the first loop in a generator, and sub-loops will be do or dowhile, until you follow a link into a new graph.

The dowhile clause is a variant of do, differing only in that it skips any trailing literal strings or newlines on its last iteration over a given set of elements. This is useful for avoiding trailing separators such as commas or spaces after the last item to be output, e.g.

      do .Process {id ', '}	produces “1.0, 1.1, 1.2,”
 dowhile .Process {id ', '}	produces “1.0, 1.1, 1.2”

Do and dowhile can also with an argument of a complex property, either a collection or a property pointing to an object or other non-property. With a collection, the loop is executed once for each item in the collection. With a property whose value is an object or other non-property, the loop is executed once for that object; if there is no object attached, the loop is not executed.

Special do and dowhile loops also exist for iterating over lines of text properties, variables etc., over all properties of an element, over decompositions and explosions, nested objects, the stack, and all graphs: see below. Also, note that the loop filtering and ordering clauses described below apply to do and dowhile loops in the same way as for foreach loops.