syberia_resource: Fetch info about a file relative to a syberia directory.
In robertzk/syberiaStructure: Syberia Structure

Description Usage Arguments Details Value

Some additional information will be returned. Namely, a list with four keys, 'current', 'cached', 'value', and 'modified'. The former two will contain information relating to the current and previous execution of this file, while 'value' contains a function that will execute the file and return its output, and 'modified' is a logical flag indicating whether or not the file has been modified since it was last executed by Syberia.

1 2	syberia_resource(filename, root = syberia_root(), provides = list(), body = TRUE, soft = FALSE, ...)

`filename`	character. The filename of the R script to execute relative to a syberia project.
`root`	character. The root of the syberia project in which to look for `filename`. The default is `syberia_root()`.
`provides`	list or environment. A list or environment of values to provide to the file.
`body`	logical. Whether or not the fetch the body of the file in the 'current' and 'cached' output lists.
`soft`	logical. Whether or not to modify the cache to reflect the file modification time and other details.
`...`	additional arguments to pass to the `base::source` function that gets executed when the 'value' is accessed.

Internally, the cached information about the file is stored in the syberia project's registry under the key resources/resource_cache.

a four-element list with names 'current', 'cached', 'value', and 'modified'. The former two will both be two-element lists containing keys 'info' and 'body' (unless Syberia has never executed the file before in which case the latter will be NULL). The 'info' key holds the result of calling R's built-in file.info on the file (and includes information like created at and modified at time), whereas the 'body' key holds a character representation of the body of the file (useful for comparing if any actual modifications have been made).

The 'value' key in the returned list holds a function which will execute the given file in the provides environment. A function is returned instead of the actual value to let the caller control whether or not the file is executed (e.g., based on its properties in the 'current' list). Most frequently, this means consulting the 'modified' key of the returned list, which will hold a logical indicating whether or not the file has been modified since last executed by Syberia (if this was never the case, 'modified' will be FALSE).

robertzk/syberiaStructure documentation built on May 27, 2019, 11:38 a.m.