(Re)initialize file system cache if it does not exist.

[wlandau-lilly]

library(memoise)
f = memoise(rnorm, cache = cache_filesystem("cache"))
dir.create("new_dir")
setwd("new_dir")
f(1) 
## Error in gzfile(file, mode) : cannot open the connection 
## In addition: Warning message: 
## In gzfile(file, mode) :
##    cannot open compressed file 'cache/75bed0259340d03b', 
##    probable reason 'No such file or directory'

Users may also want to write packages with already-memoised functions, and the users of those packages could call the functions from any working directory.

 

[jimhester]

Would be best if we just use absolute rather than relative paths when we create the cache initially.

[wlandau-lilly]

Seems like that would cover the majority of use cases.

[hadley]

Was fixed in 3a06c2c