[[bbv2.reference.modules.regex]]
= regex

Contains rules for string processing using regular expressions.

* `"x*"` matches the pattern `"x"` zero or more times.
* `"x+"` matches `"x"` one or more times.
* `"x?"` matches `"x"` zero or one time.
* `"[abcd]"` matches any of the characters, `"a"`, `"b"`, `"c"`, and
`"d"`. A character range such as `"[a-z]"` matches any character between
`"a"` and `"z"`. `"[^abc]"` matches any character which is not `"a"`,
`"b"`, or `"c"`.
* `"x|y"` matches either pattern `"x"` or pattern `"y"`
* `(x)` matches `"x"` and captures it.
* `"^"` matches the beginning of the string.
* `"$"` matches the end of the string.
* "\<" matches the beginning of a word.
* "\>" matches the end of a word.

1. [[bbv2.reference.modules.regex.split]] `rule split ( string separator )`
+
Returns a list of the following substrings:
+
.. from beginning till the first occurrence of `separator` or till the
end,
.. between each occurrence of `separator` and the next occurrence,
.. from the last occurrence of `separator` till the end.
+
If no separator is present, the result will contain only one element.

2. [[bbv2.reference.modules.regex.split-list]] `rule split-list ( list * : separator )`
+
Returns the concatenated results of applying
link:#bbv2.reference.modules.regex.split[regex.split] to every element
of the list using the separator pattern.

3. [[bbv2.reference.modules.regex.match]] `rule match ( pattern : string : indices * )`
+
Match `string` against `pattern`, and return the elements indicated by
`indices`.

4. [[bbv2.reference.modules.regex.transform]] `rule transform ( list * : pattern : indices * )`
+
Matches all elements of `list` against the `pattern` and returns a list
of elements indicated by `indices` of all successful matches. If
`indices` is omitted returns a list of first parenthesized groups of all
successful matches.

5. [[bbv2.reference.modules.regex.escape]] `rule escape ( string : symbols : escape-symbol )`
+
Escapes all of the characters in `symbols` using the escape symbol
`escape-symbol` for the given string, and returns the escaped string.

6. [[bbv2.reference.modules.regex.replace]] `rule replace ( string match replacement )`
+
Replaces occurrences of a match string in a given string and returns the
new string. The match string can be a regex expression.

7. [[bbv2.reference.modules.regex.replace-list]] `rule replace-list ( list * : match : replacement )`
+
Replaces occurrences of a match string in a given list of strings and
returns a list of new strings. The match string can be a regex
expression.

See also: link:#jam.language.rules.builtins.utility.\_match__[MATCH]