make double dot work with mcapply

[assignUser]

as mentioned in #41 thie does not work but should:

  #--- this doesn't work but is how I like to do things

myreplicate <- function(x, def) {
  age_effect <- x
  genData(2, def)
}

lapply(c(0, 5, 10), function(x) myreplicate(x, def))
#> [[1]]
#>    id age agemult
#> 1:  1  10     100
#> 2:  2  10     100
#> 
#> [[2]]
#>    id age agemult
#> 1:  1  10     100
#> 2:  2  10     100
#> 
#> [[3]]
#>    id age agemult
#> 1:  1  10     100
#> 2:  2  10     100

[assignUser]

@kgoldfeld this has to do with environments, I will look into how to maybe find way to solve this differntly but for now you can just use <<- for the assignment and it works:

library(simstudy)
def <- defData(varname = "age", formula=10, dist = "nonrandom")
def <- defData(def,
    varname = "agemult",
    formula = "age * ..age_effect", dist = "nonrandom"
)

myreplicate <- function(x, def) {
  age_effect <<- x
  genData(2, def)
}

lapply(c(0, 5, 10), function(x) myreplicate(x, def))
#> [[1]]
#>    id age agemult
#> 1:  1  10       0
#> 2:  2  10       0
#> 
#> [[2]]
#>    id age agemult
#> 1:  1  10      50
#> 2:  2  10      50
#> 
#> [[3]]
#>    id age agemult
#> 1:  1  10     100
#> 2:  2  10     100

^{Created on 2020-10-03 by the reprex package (v0.3.0.9001)}

[assignUser]

maybe explaining this trick for simulations would be somethign for the double dot vignette #52