xache

If you're like me, you probably find yourself writing some variation of the following routine in order to avoid unnecessarily performing heavy computations multiple times, across instances of R:

init <- function () {
  # do some calculation
  2 * 2 # dummy result
}

if (!exists("test")) { # Do nothing if variable exists in environment
  file <- "test.RData"
  if (!file.exists(file)) {
    load("test.RData") # Load workspace that contains the variable
  } else {
    test <- init() # Compute content of variable by calling a zero argument function
    save("test", "test.RData") # Save variable into workspace
  }
}

I wrote the xache function to be able to simplify this process to the following bit of code:

xache("test", "test.RData", init)

xache("test", "test.RData", function () {
  # do some calculation
  2 * 2 # dummy result
})

xache works as follows:

If the specified variable exists, nothing happens because there is no need to recompute its contents.
If it the variable does not exist, xache will attempt to load it from the specified RData file.
If the RData file does not exist, the specified function will evaluate the specified function, and store its results in the specified variable as well as in the RData file.

Installation

install.packages("devtools")
library("devtools")
devtools::install_github("ndejay/xache")
library("xache")

License

MIT License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.