RegExp
Defined in regexp@1.1.1
Simple regular expression.
Currently it only supports patterns below:
- Character classes: [xyz], [^xyz], ., \d, \D, \w, \W, \s,
\S, \t, \r, \n, \v, \f, [\b], x|y
- Assertions: ^, $
- Groups: (x)
- Quantifiers: x*, x+, x?, x{n}, x{n,}, x{n,m}
For details, see mdn web docs: Regular expressions.
LIMITATION:
Currently, only single byte characters (U+0001..U+007F) can be specified in character classes. Non-ASCII characters (U+0080..U+10FFFF) are encoded to two or more bytes in UTF-8, so they cannot be specified in character classes. And the null character (U+0000) cannot be used in Fix strings.
Values
namespace RegExp::RegExp
compile
Type: Std::String -> Std::String -> Std::Result Std::ErrMsg RegExp::RegExp
RegExp::compile(pattern, flags) compiles pattern into a regular expression.
flags change behavior of regular expression matching.
Currently only global flag ("g") is supported.
match_all
Type: Std::String -> RegExp::RegExp -> Std::Array (Std::Array Std::String)
regexp.match_all(target) matches target against regexp.
All matching results will be returned including captured groups.
If the match against the regular expression fails, an empty array is returned.
This function is similar to String.matchAll() function of JavaScript.
match_one
Type: Std::String -> RegExp::RegExp -> Std::Result Std::ErrMsg (Std::Array Std::String)
regexp.match(target) matches target against regexp.
If the global flag ("g") is not set, it returns an array of the groups of the first match.
Group 0 is a substring that matches the entire regular expression.
Group 1 and beyond are the captured substrings in each group. If not captured, the group will be an empty string.
Example:
let regexp = RegExp::compile("[a-z]+([0-9]+)", "").as_ok;
let groups = regexp.match_one("abc012 def345").as_ok;
// groups == ["abc012", "012"]
If the global flag ("g") is set, all matching results will be returned, but captured groups will not be included.
Example:
let regexp = RegExp::compile("[a-z]+([0-9]+)", "g").as_ok;
let groups = regexp.match_one("abc012 def345").as_ok;
// groups == ["abc012", "def345"]
If the match against the regular expression fails, an error "NotMatch" is reported.
This function is similar to String.match() function of JavaScript.
replace_all
Type: Std::String -> Std::String -> RegExp::RegExp -> Std::String
regexp.replace_all(target, replacement) matches target against regexp,
and replace all matching substrings with replacement.
If replacement contains $&, it is substituted with entire matched substring.
If replacement contains $n where n is an integer, it is substituted with
the captured group.
If replacement contains $$, it is substituted with single $.
Example:
let regexp = RegExp::compile("(\\w\\w)(\\w)", "").as_ok;
let result = regexp.replace_all("abc def ijk", "$2$1");
// result == "cab fde kij"
This function is similar to String.replaceAll()
function of JavaScript.
Note that $', $`, $<Name> are not supported yet.
Types and aliases
namespace RegExp
RegExp
Defined as: type RegExp = unbox struct { ...fields... }
Type of a compiled regular expression.
field flags
Type: Std::String
field nfa
Type: RegExp.RegExpNFA::NFA