cachefun

The goal of cachefun is to make caching fun ;-)

It let's you define "cache-aware functions"" (cafuns) or, put differently, functions that have an internal/built-in cache.

Whether or not you want to cache to be updated upon every execuction of the function or not is completely up to you (see refresh argument of cafun_create):

• When setting refresh = TRUE the cafun would behave just as any regular R function
• When setting refresh = FALSE you would explicitly request the cached result of the previous execution.

The main use case I had in mind when developping this package was offering effortless iternal caching for functions that take a long time to run (e.g. loading data, tidying data).

Installation

require("devtools")
devtools::install_github("rappster/cachefun")

Examples

Introduction

library(cachefun)
# Define a regular function that you'd like to make "cache-aware"
fun <- function() Sys.time()

# Turn this function into a cache-aware function
cafun <- cafun_create(fun = fun)

str(cafun)
#> function (fun = function () 
#> Sys.time(), refresh = TRUE, reset = FALSE, .verbose = FALSE, ...)
# Note that default value for arg 'refresh = TRUE' >> by default, the inner
# function is always execudted (no internal cache used)  which implies that you
# need to explicitly state whenever you would like to use the internal cache

cafun() # Inner function executed, result is cached
#> [1] "2018-02-04 18:40:46 CET"
cafun() # Inner function executed, result is cached
#> [1] "2018-02-04 18:40:46 CET"
cafun(refresh = FALSE) # Inner function NOT executed, internal cache returned
#> [1] "2018-02-04 18:40:46 CET"
cafun(refresh = FALSE) # Inner function NOT executed, internal cache returned
#> [1] "2018-02-04 18:40:46 CET"
cafun() # Inner function executed, result is cached
#> [1] "2018-02-04 18:40:46 CET"
cafun(refresh = FALSE) # Inner function NOT executed, internal cache returned
#> [1] "2018-02-04 18:40:46 CET"

Change the default value of args

cafun <- cafun_create(fun = fun, .refresh = FALSE)
#> Error in cafun_create(fun = fun, .refresh = FALSE): Objekt 'fun' nicht gefunden

str(cafun)
#> Error in str(cafun): Objekt 'cafun' nicht gefunden
# Note that default value for arg 'refresh = TRUE' >> you reversed the
# pre-configured default setting

cafun() # Inner is INITIALLY function executed, result is cached
#> Error in cafun(): konnte Funktion "cafun" nicht finden
cafun() # Inner function NOT executed, internal cache returned
#> Error in cafun(): konnte Funktion "cafun" nicht finden
cafun(refresh = TRUE) # Explicit refresh request:
#> Error in cafun(refresh = TRUE): konnte Funktion "cafun" nicht finden
                      # Inner function executed, result is cached
cafun() # Inner function NOT executed, internal cache returned
#> Error in cafun(): konnte Funktion "cafun" nicht finden

Inner function with argumeents

fun <- function(x) Sys.time() + x

cafun <- cafun_create(fun = fun)

cafun(x = 3600) # Inner function executed, result is cached
#> [1] "2018-02-04 19:42:22 CET"
cafun(x = 3600 * 5, refresh = FALSE) # Inner function NOT executed, internal cache returned
#> [1] "2018-02-04 19:42:22 CET"
cafun(x = 3600 * 5) # Inner function executed, result is cached
#> [1] "2018-02-04 23:42:22 CET"

Reset internal cache

fun <- function(x) rnorm(x)

cafun <- cafun_create(fun = fun)

res <- cafun(x = 1000)

# Resetting the internal cache in verbose mode (messages for prior and new
# object size in cache)
cafun_reset_cache(cafun = cafun, .verbose = TRUE)
#> 8040
#> 0