Create, Set, and Get Injectors (Modulr Internal States).

Create an new injector, set and get the current injector, and get the default injector.

new_injector()

set_injector(injector = new_injector())

set_default_injector()

get_injector()

get_default_injector()

Arguments

injector	An injector returned by new_injector.

Value

Every function returns an injector (R environment).

Details

An injector essentially carries an internal modulr state. Technically, it is is an R environment containing every piece of information needed by modulr to reflect the module definitions, the dependencies between them, the configurations, and all the associated metadata. As a PORO (Plain Old R Object), an injector can be stored to disk with the session data, or shared between Alice and Bob, for instance.

When the modulr package is loaded, a default injector is created. This injector is returned by the get_default_injector function.

Warning

Setting an injector from within a module is not allowed and results in an error.

See also

.SharedEnv, define, list_modules, make, and reset.

Examples

reset()
#> [2017-06-21T21:58:22 UTC] Resetting modulr state ... OK
define("foo", NULL, function() NULL)
#> [2017-06-21T21:58:22 UTC] Defining 'foo' ... OK
injector <- new_injector()
previous_injector <- set_injector(injector)
define("bar", NULL, function() NULL)
#> [2017-06-21T21:58:22 UTC] Defining 'bar' ... OK
lsmod()
#>   name version   storage along type weight calls dependencies uses      size
#> 1  bar    <NA> in-memory  <NA> <NA>   <NA>     0            0    0 888 bytes
#>   lines                modified
#> 1     2 2017-06-21T21:58:22 UTC
set_injector(previous_injector)
#> <environment: 0x9edb7d0>
lsmod()
#>   name version   storage along type weight calls dependencies uses      size
#> 1  foo    <NA> in-memory  <NA> <NA>   <NA>     0            0    0 888 bytes
#>   lines                modified
#> 1     2 2017-06-21T21:58:22 UTC

not_run({
  .Last <- function() {
   # Bind the current injector (internal modulr state) to the environment.
   injector <- get_injector()
  }
  quit(save = "yes")
})

reset()
#> [2017-06-21T21:58:22 UTC] Resetting modulr state ... OK
define("foo", NULL, function() "Hi Bob!")
#> [2017-06-21T21:58:22 UTC] Defining 'foo' ... OK
## Alice saves its injector and sends it to ...
saveRDS(get_injector(), file = "injector.R")
## ... Bob who restores it.
injector <- readRDS("injector.R")
set_injector(injector)
#> <environment: 0x7d97570>
make("foo")
#> [2017-06-21T21:58:23 UTC] Making 'foo' ...
#> [2017-06-21T21:58:23 UTC] * Visiting and defining dependencies ...
#> [2017-06-21T21:58:23 UTC] * Constructing dependency graph ... OK
#> [2017-06-21T21:58:23 UTC] DONE ('foo' in 0.011 secs)
#> [1] "Hi Bob!"