opts_list: Constructive options for type 'list'

In constructive: Display Idiomatic Code to Construct Most R Objects

Constructive options for type 'list'

Description

These options will be used on objects of type 'list'.

Usage

opts_list(
  constructor = c("list", "list2"),
  ...,
  trim = NULL,
  fill = c("vector", "new_list", "+", "...", "none")
)

Arguments

constructor	String. Name of the function used to construct the object, see Details section.
...	Additional options used by user defined constructors through the opts object
trim	NULL or integerish. Maximum of elements showed before it's trimmed. Note that it will necessarily produce code that doesn't reproduce the input. This code will parse without failure but its evaluation might fail.
fill	String. Method to use to represent the trimmed elements.

Details

Depending on constructor, we construct the object as follows:

• "list" (default): Build the object by calling list().

• "list2": Build the object by calling rlang::list2(), the only difference with the above is that we keep a trailing comma when the list is not trimmed and the call spans several lines.

If trim is provided, depending on fill we will present trimmed elements as followed:

• "vector" (default): Use vector(), so for instance list("a", "b", "c") might become c(list("a"), vector("list", 2)).

• "new_list": Use rlang::new_list(), so for instance list("a", "b", "c") might become c(list("a"), rlang::new_list(2)).

• "+": Use unary +, so for instance list("a", "b", "c") might become list("a", +2).

• "...": Use ..., so for instance list("a", "b", "c") might become list("a", ...)

• "none": Don't represent trimmed elements.

When trim is used the output is parsable but might not be possible to evaluate, especially with fill = "...". In that case you might want to set check = FALSE

Value

An object of class <constructive_options/constructive_options_list>

constructive documentation built on April 3, 2025, 9:39 p.m.