[R-pkgs] gestalt: Tools for Making and Combining Functions

[Eugene Ha]

Dear R Users,
 
The gestalt package (0.1.1) has been published on CRAN:
https://cran.r-project.org/package=gestalt

It provides a suite of function-building tools centered around a
(forward) composition operator, '%>>>%', which extends the semantics
of the magrittr '%>%' operator and supports tidyverse quasiquotation.
Aside from making your functions more modular, the main benefit of
'%>>>%' is its ability to make composite functions that can be
inspected and transformed as list-like objects.

As an illustration, you can sample, capitalize, and join (character)
vectors with the following composite function:

  draw <- sample %>>>% toupper %>>>% paste(collapse = "")
  
  set.seed(1)
  draw(letters, 5)
  #> [1] “GJNUE"

But because the composite function 'draw()' is list-like, you can also
inspect its intermediate results using a standard map-reduce strategy:

  stepwise <- lapply(`%>>>%`, print) %>>>% compose
  
  set.seed(1)
  stepwise(draw)(letters, 5)
  #> [1] "g" "j" "n" "u" "e"
  #> [1] "G" "J" "N" "U" "E"
  #> [1] "GJNUE"

In conjunction with '%>>>%', a compact function constructor, 'fn()',
and a function that performs partial application, 'partial()', are
also provided. Both support quasiquotation.

Learn more from

- the landing page of the source repository:
  https://github.com/egnha/gestalt

- the package vignette, which gives an overview through examples:
  https://cran.r-project.org/package=gestalt/vignettes/gestalt.html

Bug reports and other feedback are welcome at the GitHub issues page:
https://github.com/egnha/gestalt/issues

Eugene Ha