get_digest: Get the Digest of a Module.

In openscienceunil/modulr: A Dependency Injection Framework for R

Description

Get the digest (a xxHash64 hash of the dependencies and provider) of a module.

Usage

get_digest(name = .Last.name, load = FALSE)

Arguments

name	A string (character vector of lenght one). A module name can contain letters, figures and some special characters, namely _, -, and /. The latter is a namespace separator. Names containing /mock/, /mocks/, /test/, /tests/, /example/, or /examples/ have a special meaning related to code testing and examples. The name "modulr" corresponds to a special module and is therefore reserved.
load	A flag. Should an undefined module be implicitely loaded?

Details

A digest is useful for comparing two modules. For instance, in order to know if a module definition has changed, a digest of the newly presented module is computed and compared to the existing one. When a module is imported from an URL, it is also possible to specify a digest. The imported module is then rejected if its digest differs from the expected value.

Value

A string containing the digest of the module.

Warning

It is considered a very bad practice to define, touch, undefine, load, make, reset, or perform any other operation from within a module definition that may alterate the internal state of modulr.

See Also

define and root_config.

Examples

reset()
define("foo", NULL, function() NULL)
get_digest("foo")

reset()
tmp_dir <- tempfile("modulr_")
dir.create(tmp_dir)
tmp_file <- file.path(tmp_dir, "foo.R")
cat('define("foo", NULL, function() NULL)', file = tmp_file)
root_config$set(tmp_dir)
## Not run: get_digest("foo", load = FALSE)
get_digest("foo", load = TRUE)
unlink(tmp_dir, recursive = TRUE)

openscienceunil/modulr documentation built on May 3, 2019, 5:49 p.m.