str_out: Formatting Utilities

In pkgmaker: Package development utilities

Description

str_out formats character vectors for use in show methods or error/warning messages.

str_desc builds formatted string from a list of complex values.

str_fun extracts and formats a function signature. It typically formats the output capture.output(args(object)).

str_bs substitutes backspace characters (\b) to produce a character string as it would be displayed in the console.

Usage

  str_out(x, max = 3L, quote = is.character(x),
    use.names = FALSE, sep = ", ", total = FALSE)

  str_desc(object, exdent = 0L)

  str_fun(object)

  str_bs(x)

Arguments

x	character vector
max	maximum number of values to appear in the list. If x has more elements than max, a "..." suffix is appended.
quote	a logical indicating whether the values should be quoted with single quotes (defaults) or not.
use.names	a logical indicating whether names should be added to the list as NAME=VAL, ... or not (default).
sep	separator character
total	logical that indicates if the total number of elements should be appended to the formatted string as "'a', ..., 'z' (<N> total)".
object	an R object
exdent	extra indentation passed to str_wrap, and used if the output should spread over more than one lines.

Value

a single character string

Author(s)

Renaud Gaujoux

str_bs was adapted from a proposal from Yihui Xie.

Examples

#----------
# str_out
#----------
x <- letters[1:10]
str_out(x)
str_out(x, 8)
str_out(x, Inf)
str_out(x, quote=FALSE)
str_out(x, total = TRUE)

#----------
# str_fun
#----------
str_fun(install.packages)

#----------
# str_bs
#----------
# Backspace substitution
str_bs("abc")
str_bs("abc\b")
str_bs("abc\b\b")
str_bs("abc\bd")
str_bs("abc\b\bde\b")

# more complex example
x <- "\bab\nc\bd\n\babc\b\bd"
cat(x, "\n")
y <- str_bs(x)
y
cat(y, "\n")

pkgmaker documentation built on May 2, 2019, 4:42 p.m.