usage {formatR} | R Documentation |
Show the usage of a function
Description
Print the reformatted usage of a function. The arguments of the function are
searched by argsAnywhere()
, so the function can be either
exported or non-exported from a package. S3 methods will be marked.
Usage
usage(
FUN,
width = getOption("width"),
tidy = TRUE,
output = TRUE,
indent.by.FUN = FALSE,
fail = c("warn", "stop", "none")
)
Arguments
FUN |
The function name. |
width |
The width of the output. |
tidy |
Whether to reformat the usage code. |
output |
Whether to print the output to the console (via
|
indent.by.FUN |
Whether to indent subsequent lines by the width of the function name (see “Details”). |
fail |
A character string that represents the action taken when the width constraint is unfulfillable. "warn" and "stop" will signal warnings and errors, while "none" will do nothing. |
Details
Line breaks in the output occur between arguments. In particular, default values of arguments will not be split across lines.
When indent.by.FUN
is FALSE
, indentation is set by the option
getOption("formatR.indent", 4L)
, the default value of the
indent
argument of tidy_source()
.
Value
Reformatted usage code of a function, in character strings (invisible).
See Also
Examples
library(formatR)
usage(var)
usage(plot)
usage(plot.default) # default method
usage("plot.lm") # on the 'lm' class
usage(usage)
usage(barplot.default, width = 60) # output lines have 60 characters or less
# indent by width of 'barplot('
usage(barplot.default, width = 60, indent.by.FUN = TRUE)
## Not run:
# a warning is raised because the width constraint is unfulfillable
usage(barplot.default, width = 30)
## End(Not run)