Default Item Context

Helper function to provide a contextual default value.

Usage

get_context()

Value

a character value or NULL

Details

Since the project YAML config has been introduced (v0.8.0), all core functions require to provide the name (id) of the item group to manipulate.

At the grammar level functions, this argument needs to be collected to pass it's value to the core level functions.

When used inside the module server (one instance is dedicated to a specific item group) or any custom code applied to a single item group, it would be tidious to repeat this argument with the same value for each call.

By setting item = get_context(), the argument will get it's value from the environment in which the function was called.

Examples

# baseline
config <- design(project = "test", item = "foo")

# instead of
config |> extend(item = "foo", attribute = c(name = "total", type = "integer"))
#> $version
#> [1] "0.8.0.9000"
#> 
#> $project
#> [1] "test"
#> 
#> $items
#> $items[[1]]
#> $items[[1]]$id
#> [1] "foo"
#> 
#> $items[[1]]$source
#> $items[[1]]$source$type
#> [1] "file"
#> 
#> $items[[1]]$source$path
#> [1] "foo"
#> 
#> $items[[1]]$source$filename
#> [1] "foo_items.csv"
#> 
#> 
#> $items[[1]]$data.model
#> $items[[1]]$data.model$attributes
#> $items[[1]]$data.model$attributes[[1]]
#> $items[[1]]$data.model$attributes[[1]]$name
#> [1] "id"
#> 
#> $items[[1]]$data.model$attributes[[1]]$type
#> [1] "numeric"
#> 
#> $items[[1]]$data.model$attributes[[1]]$default
#> [1] "ktools::uuid()"
#> 
#> 
#> $items[[1]]$data.model$attributes[[2]]
#> $items[[1]]$data.model$attributes[[2]]$name
#> [1] "total"
#> 
#> $items[[1]]$data.model$attributes[[2]]$type
#> [1] "integer"
#> 
#> 
#> 
#> $items[[1]]$data.model$skip
#> [1] "id"
#> 
#> $items[[1]]$data.model$hide
#> [1] "id"
#> 
#> 
#> 
#> 

# one can do
item <- "foo"
config |> extend(attribute = c(name = "total", type = "integer"))
#> $version
#> [1] "0.8.0.9000"
#> 
#> $project
#> [1] "test"
#> 
#> $items
#> $items[[1]]
#> $items[[1]]$id
#> [1] "foo"
#> 
#> $items[[1]]$source
#> $items[[1]]$source$type
#> [1] "file"
#> 
#> $items[[1]]$source$path
#> [1] "foo"
#> 
#> $items[[1]]$source$filename
#> [1] "foo_items.csv"
#> 
#> 
#> $items[[1]]$data.model
#> $items[[1]]$data.model$attributes
#> $items[[1]]$data.model$attributes[[1]]
#> $items[[1]]$data.model$attributes[[1]]$name
#> [1] "id"
#> 
#> $items[[1]]$data.model$attributes[[1]]$type
#> [1] "numeric"
#> 
#> $items[[1]]$data.model$attributes[[1]]$default
#> [1] "ktools::uuid()"
#> 
#> 
#> $items[[1]]$data.model$attributes[[2]]
#> $items[[1]]$data.model$attributes[[2]]$name
#> [1] "total"
#> 
#> $items[[1]]$data.model$attributes[[2]]$type
#> [1] "integer"
#> 
#> 
#> 
#> $items[[1]]$data.model$skip
#> [1] "id"
#> 
#> $items[[1]]$data.model$hide
#> [1] "id"
#> 
#> 
#> 
#>