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Declare a format's reader options

Source: R/format-options.R
format_opt.Rd

The option kinds an entry may declare through register_format()'s options argument. Each returns one spec: a label, a default, and enough shape for a block to render a field and read it back.

Usage

opt_choice(label, choices, default, create = FALSE)

opt_text(label, default = "", placeholder = NULL)

opt_number(label, default = 0, placeholder = NULL)

opt_flag(label, default = TRUE)

Arguments

label

Field label, shown to the user.

choices

Named character vector of choices (names are labels).

default

The value the reader uses when the option is unset.

create

For opt_choice(), whether the user may type a value that is not in choices.

placeholder

Hint shown in an empty field. Defaults to naming the default value.

Value

A blockr_format_opt object.

Details

A value equal to the declared default is dropped when a block collects its options, so a block nobody has touched carries no options at all and serializes clean.

See also

register_format(), format_options()