strtrim_ctl: ANSI Control Sequence Aware Version of strtrim

Description

One difference with base::strtrim is that all C0 control characters such as newlines, carriage returns, etc., are treated as zero width.

Usage

strtrim_ctl(x, width, warn = getOption("fansi.warn"), ctl = "all")
strtrim2_ctl(x, width, warn = getOption("fansi.warn"),
  tabs.as.spaces = getOption("fansi.tabs.as.spaces"),
  tab.stops = getOption("fansi.tab.stops"), ctl = "all")
strtrim_sgr(x, width, warn = getOption("fansi.warn"))
strtrim2_sgr(x, width, warn = getOption("fansi.warn"),
  tabs.as.spaces = getOption("fansi.tabs.as.spaces"),
  tab.stops = getOption("fansi.tab.stops"))

Arguments

a character vector, or an object which can be coerced to a character vector by as.character.

width

Positive integer values: recycled to the length of x.

warn

TRUE (default) or FALSE, whether to warn when potentially problematic Control Sequences are encountered. These could cause the assumptions fansi makes about how strings are rendered on your display to be incorrect, for example by moving the cursor (see fansi).

ctl

character, which Control Sequences should be treated specially. See the "_ctl vs. _sgr" section for details.

"nl": newlines.
"c0": all other "C0" control characters (i.e. 0x01-0x1f, 0x7F), except for newlines and the actual ESC (0x1B) character.
"sgr": ANSI CSI SGR sequences.
"csi": all non-SGR ANSI CSI sequences.
"esc": all other escape sequences.
"all": all of the above, except when used in combination with any of the above, in which case it means "all but".

tabs.as.spaces

FALSE (default) or TRUE, whether to convert tabs to spaces. This can only be set to TRUE if strip.spaces is FALSE.

tab.stops

integer(1:n) indicating position of tab stops to use when converting tabs to spaces. If there are more tabs in a line than defined tab stops the last tab stop is re-used. For the purposes of applying tab stops, each input line is considered a line and the character count begins from the beginning of the input line.

_ctl vs. _sgr

The *_ctl versions of the functions treat all Control Sequences specially by default. Special treatment is context dependent, and may include detecting them and/or computing their display/character width as zero. For the SGR subset of the ANSI CSI sequences, fansi will also parse, interpret, and reapply the text styles they encode if needed. You can modify whether a Control Sequence is treated specially with the ctl parameter. You can exclude a type of Control Sequence from special treatment by combining "all" with that type of sequence (e.g. ctl=c("all", "nl") for special treatment of all Control Sequences but newlines). The *_sgr versions only treat ANSI CSI SGR sequences specially, and are equivalent to the *_ctl versions with the ctl parameter set to "sgr".

Details

strtrim2_ctl adds the option of converting tabs to spaces before trimming. This is the only difference between strtrim_ctl and strtrim2_ctl.

Examples

Run this code

# NOT RUN {
strtrim_ctl("\033[42mHello world\033[m", 6)
# }