A convenience function to tune the ICU regular expressions
matcher's behavior, e.g., in stri_count_regex
and other stringi-search-regex functions.
stri_opts_regex(
case_insensitive,
comments,
dotall,
dot_all = dotall,
literal,
multiline,
multi_line = multiline,
unix_lines,
uword,
error_on_unknown_escapes,
time_limit = 0L,
stack_limit = 0L,
...
)Returns a named list object; missing settings are left with default values.
logical; enables case insensitive matching [regex flag (?i)]
logical; allows white space and comments within patterns [regex flag (?x)]
logical; if set, `.` matches line terminators,
otherwise matching of `.` stops at a line end [regex flag (?s)]
alias of dotall
logical; if set, treat the entire pattern as a literal string: metacharacters or escape sequences in the input sequence will be given no special meaning; note that in most cases you would rather use the stringi-search-fixed facilities in this case
logical; controls the behavior of `$` and `^`.
If set, recognize line terminators within a string, otherwise,
match only at start and end of input string [regex flag (?m)]
alias of multiline
logical; Unix-only line endings;
when enabled, only U+000a is recognized as a
line ending by `.`, `$`, and `^`.
logical; Unicode word boundaries;
if set, uses the Unicode TR 29 definition of word boundaries;
warning: Unicode word boundaries are quite different from traditional
regex word boundaries. [regex flag (?w)]
See https://unicode.org/reports/tr29/#Word_Boundaries
logical; whether to generate an error on unrecognized backslash escapes; if set, fail with an error on patterns that contain backslash-escaped ASCII letters without a known special meaning; otherwise, these escaped letters represent themselves
integer; processing time limit, in ~milliseconds (but not precisely so, depends on the CPU speed), for match operations; setting a limit is desirable if poorly written regexes are expected on input; 0 for no limit
integer; maximal size, in bytes, of the heap storage available for the match backtracking stack; setting a limit is desirable if poorly written regexes are expected on input; 0 for no limit
[DEPRECATED] any other arguments passed to this function generate a warning; this argument will be removed in the future
Marek Gagolewski and other contributors
Note that some regex settings may be changed using ICU regex flags
inside regexes. For example, '(?i)pattern' performs
a case-insensitive match of a given pattern,
see the ICU User Guide entry on Regular Expressions
in the References section or stringi-search-regex.
enum URegexpFlag: Constants for Regular Expression Match Modes
-- ICU4C API Documentation,
https://unicode-org.github.io/icu-docs/apidoc/dev/icu4c/uregex_8h.html
Regular Expressions -- ICU User Guide, https://unicode-org.github.io/icu/userguide/strings/regexp.html
The official online manual of stringi at https://stringi.gagolewski.com/
Other search_regex:
about_search_regex,
about_search
stri_detect_regex('ala', 'ALA') # case-sensitive by default
stri_detect_regex('ala', 'ALA', opts_regex=stri_opts_regex(case_insensitive=TRUE))
stri_detect_regex('ala', 'ALA', case_insensitive=TRUE) # equivalent
stri_detect_regex('ala', '(?i)ALA') # equivalent
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