[R-pkgs] New Package: lrequire v0.1.3 - use modules to encapsulate and cache your R scripts

Rick Wargo
Mon, 22 Feb 2016 18:03:18 -0000

Dear R Users,

I am happy to announce the initial release (v0.1.3) of
lrequire<https://cran.r-project.org/web/packages/lrequire/>, now available
on CRAN.

https://cran.r-project.org/web/packages/lrequire/

lrequire supports modularization of R Scripts, enabling encapsulation of
information and caching of scripts. This is very similar to the
require()<https://nodejs.org/api/modules.html> support in
node.js<https://nodejs.org/>.

Use of lrequire encourages separation of responsibility and using modules to
encapsulate specific functionality. This leads to more easily-maintained scripts
and encourages reuse.
lrequire also cache loaded modules (scripts) such that the next load (source) of
the script does not execute its contents, unless specified. For example, if a
module is built around sourcing a slowly-changing dataset that is time-consuming
to retrieve, frequent reloads of the module will only return the cached copy of
the data, saving the time expense. I found this very useful for developing
dashboard components ? lrequire permitted me the freedom to keep tweaking the UI
without having to wait for the live reload of the data.

How It Works

Goal: build a reusable module to welcome an individual. Any environment
artifacts necessary to build that module are encapsulated in the lrequire() call
and only the functionality is returned.

For example:

________________________________

File: welcome.R

data.that.will.not.be.exposed <- 'some work'

hello <- function(person.name) {
  return (paste0('Hello, ', person.name, '!'))
}

module.exports = hello

________________________________

File: main.R

hello <- lrequire(welcome)

hello('Rick')

________________________________

Note that the variable declared in welcome.R will not be visible in main.R only
the hello() function. Multiple pieces of information can be exposed by returning
a list() object in module.exports. Refer to the documentation for details.

All the best,
Rick Wargo
https://linkedin.com/in/rickwargo/
https://www.rickwargo.com/
@rickwargo


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