Removes any whitespace before the first and/or after the last non-Control
Sequence character. Unlike with the base::trimws, only the default
whitespace specification is supported.
trimws_ctl(
x,
which = c("both", "left", "right"),
whitespace = "[ \t\r\n]",
warn = getOption("fansi.warn", TRUE),
term.cap = getOption("fansi.term.cap", dflt_term_cap()),
ctl = "all",
normalize = getOption("fansi.normalize", FALSE)
)The input with white space removed as described.
a character vector
a character string specifying whether to remove both
leading and trailing whitespace (default), or only leading
("left") or trailing ("right"). Can be abbreviated.
must be set to the default value, in the future it may become possible to change this parameter.
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).
At most one warning will be issued per element in each input vector. Will
also warn about some badly encoded UTF-8 strings, but a lack of UTF-8
warnings is not a guarantee of correct encoding (use validUTF8 for
that).
character a vector of the capabilities of the terminal, can
be any combination of "bright" (SGR codes 90-97, 100-107), "256" (SGR codes
starting with "38;5" or "48;5"), "truecolor" (SGR codes starting with
"38;2" or "48;2"), and "all". "all" behaves as it does for the ctl
parameter: "all" combined with any other value means all terminal
capabilities except that one. fansi will warn if it encounters SGR codes
that exceed the terminal capabilities specified (see term_cap_test
for details). In versions prior to 1.0, fansi would also skip exceeding
SGRs entirely instead of interpreting them. You may add the string "old"
to any otherwise valid term.cap spec to restore the pre 1.0 behavior.
"old" will not interact with "all" the way other valid values for this
parameter do.
character, which Control Sequences should be treated
specially. 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, and OSC hyperlinks, fansi
will also parse, interpret, and reapply the sequences as needed. You can
modify whether a Control Sequence is treated specially with the ctl
parameter.
"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.
"url": OSC hyperlinks
"osc": all non-OSC-hyperlink OSC 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".
TRUE or FALSE (default) whether SGR sequence should be
normalized out such that there is one distinct sequence for each SGR code.
normalized strings will occupy more space (e.g. "\033[31;42m" becomes
"\033[31m\033[42m"), but will work better with code that assumes each SGR
code will be in its own escape as crayon does.
Control Sequences are non-printing characters or sequences of characters.
Special Sequences are a subset of the Control Sequences, and include CSI
SGR sequences which can be used to change rendered appearance of text, and
OSC hyperlinks. See fansi for details.
Several factors could affect the exact output produced by fansi
functions across versions of fansi, R, and/or across systems.
In general it is best not to rely on exact fansi output, e.g. by
embedding it in tests.
Width and grapheme calculations depend on locale, Unicode database
version, and grapheme processing logic (which is still in development), among
other things. For the most part fansi (currently) uses the internals of
base::nchar(type='width'), but there are exceptions and this may change in
the future.
How a particular display format is encoded in Control Sequences is
not guaranteed to be stable across fansi versions. Additionally, which
Special Sequences are re-encoded vs transcribed untouched may change.
In general we will strive to keep the rendered appearance stable.
To maximize the odds of getting stable output set normalize_state to
TRUE and type to "chars" in functions that allow it, and
set term.cap to a specific set of capabilities.
trimws_ctl(" \033[31m\thello world\t\033[39m ")
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