• BREAKING CHANGE: Deprecated Pipeline$save() and changed the arguments for save_pipeline(), show_pipeline(), and Pipeline$annotate(). This change was made to support the next change which is:

• Added support for nomnoml flowcharts:

• By default, show_pipeline() will now display a nomnoml style flowchart. You can reproduce the old visNetwork style chart using show_pipeline(as="visnetwork"). These are powered by two new methods belonging to the Pipeline class: $nomnoml() and $visnetwork().
• By default, save_pipeline() will now save an image of the nomnoml chart. You can export the visNetwork chart as an html file using save_pipeline(as="visnetwork"). These are powered by two new methods belonging to the Pipeline class, which replace the deprecated $save() method: $save_nomnoml() and $save_visnetwork(). • Added note and label arguments to make_*(). This allows makepipe code to be even more self documenting, since notes that might be left as comments above the make_*() segment can now be incorporated into the pipeline itself. • make_with_*() no longer throws an error if dependencies don’t exist. It will be left to the users script/code to handle this situation. • Fixed a bug which prevented make_with_recipe() from accepting long (>10 line) recipes • Added reset_pipeline(), a wrapper for set_pipeline(Pipeline$new()), for resetting the active pipeline

### make_*()

• Made dependencies argument to make_*() optional (#25).

• Added a force argument to make_*() (#26). This allows the user to override the default conditional execution logic to ensure that a given segment of the pipeline is run no matter what.

### Segment

• Implemented Segment class to serve as the basic building block for the Pipeline (#28). This clarifies the link between the fundamental make_*() functions and the Pipeline object. In particular, each make_*() call constructs a Segment which is appended to the Pipeline.

• The Segment class has an execute() method, which replicates the execution behaviour of the make_*() functions. Hence Segment$execute() can be run to rebuild the targets associated with a given segment without adding a new segment to the Pipeline as would be done if we called make_*() again. • The Segment holds all execution metadata (e.g. execution result, executiontime, etc.). This is updated via the Segment$update_result() method whenever Segment$execute() is called. • Added a build() method to the Pipeline class, which sorts the Segments topologically and then calls execute() on each in turn. • Added a clean() method to the Pipeline class, which deletes the targets associated with each Segment. • Removed the now redundant makepipe_result S3 class. All of the information that was held by the makepipe_result is now held by the Segment. ### Bug fixes • Fixed a minor bug in Pipeline$print() which was causing user-supplied annotations to be overwritten (#23).

• Fixed a minor bug in make_register() (#22). Previously, an error would be thrown when using make_register() outside of a makepipe segment if the user set quiet=TRUE. This is no longer the case.

### Documentation

• Added a getting started vignette (#19).
• Fixed minor bug having to do with the propagation of out-of-dateness in Pipeline visualizations.
• Renamed package from piper to makepipe (#11).

• Both make_with_recipe() and make_with_source() now return an object of class makepipe_result (#2, #14). Along with metadata relating to the execution, this object contains a result element which:

• If using make_with_recipe(), is identical with whatever the recipe returns
• If using make_with_source(), is a list containing any objects registered in the source script using make_register()
• The execution environment for make_*() is now, by default, a fresh environment whose parent is the calling environment. This can be overridden using the envir argument.

• Added arguments to save_pipeline() and show_pipeline(), allowing the user to specify e.g. height and width of output widgets.

• Added packages argument to make_*() functions, allowing the user to easily add packages as dependencies of their targets. If any of the packages specified have been updated since the targets were last produced, the targets will be registered as out-of-date when make_*() is run.

• Pipeline visualisations are now sorted hierarchically, from left to right across the screen.
• Fixed bug in pipeline invalidation (#4).
• Added a NEWS.md file to track changes to the package.
• Initial release.