anchor.diff:  <2> `by('name')` will process the grouped elements by their name (*element property projection*).
   <3> `by(count())` will count the number of elements in each group (*traversal*).
   
  +The following steps all support `by()`-modulation. Note that the semantics of such modulation should be understood
  +on a step-by-step level and thus, as discussed in their respective section of the documentation.
  +
  +* <<dedup-step, `dedup()`>>: dedup on the results of a `by()`-modulation.
  +* <<cyclicpath-step, `cyclicPath()`>>: filter if the traverser's path is cyclic given `by()`-modulation.
  +* <<simplepath-step, `simplePath()`>>: filter if the traverser's path is simple given `by()`-modulation.
  +* <<sample-step, `sample()`>>: sample using the value returned by `by()`-modulation.
  +* <<where-step, `where()`>>: determine the predicate given the testing of the results of `by()`-modulation.
  +* <<groupCount-step,`groupCount()`>>: count those groups where the group keys are the result of `by()`-modulation.
  +* <<group-step, `group()`>>: create group keys and values according to `by()`-modulation.
  +* <<order-step, `order()`>>: order the objects by the results of a `by()`-modulation.
  +* <<path-step, `path()`>>: get the path of the traverser where each path element is `by()`-modulated.
  +* <<project-step, `project()`>>: project a map of results given various `by()`-modulations off the current object.
  +* <<select-step, `select()`>>: select path elements and transform them via `by()`-modulation.
  +* <<tree-step, `tree()`>>: get a tree of traversers objects where the objects have been `by()`-modulated.
  +* <<aggregate-step, `aggregate()`>>: aggregate all objects into a set but only store their `by()`-modulated values.
  +* <<store-step, `store()`>>: store all objects into a set but only store their `by()`-modulated values.
  +
   [[cap-step]]
   Cap Step
   ~~~~~~~~
  
positive.code: The `from()`-step is not an actual step, but instead is a "step-modulator" similar to <<as-step,`as()`>> and
  <<by-step,`by()`>>. If a step is able to accept traversals or strings then `from()` is the
  means by which they are added. The general pattern is `step().from()`. See <<to-step,`to()`>>-step.
  
  [[group-step]]
  Group Step
  
negative.code: Option Step
  ~~~~~~~~~~~
  
  An option to a <<branch-step,`branch()`>> or <<choose-step,`choose()`>>.
  
  [[optional-step]]
  Optional Step
  