gleam/regex
This module contains regular expression matching functions for strings. The matching algorithms of the library are based on the PCRE library, but not all of the PCRE library is interfaced and some parts of the library go beyond what PCRE offers. Currently PCRE version 8.40 (release date 2017-01-11) is used.
Types
CompileError
The full string of the match. The byte index of the match in the original string. A Regex can have subpatterns, sup-parts that are in parentheses. When a regular expression fails to compile:
pub type CompileError { CompileError(error: String, byte_index: Int) }
Constructors
-
CompileError(error: String, byte_index: Int)
Match
The details about a particular match:
pub type Match { Match( content: String, byte_index: Int, submatches: List(Option(String)), ) }
Constructors
-
Match( content: String, byte_index: Int, submatches: List(Option(String)), )
Options
The problem encountered that caused the compilation to fail The byte index into the string to where the problem was found
pub type Options { Options(case_insensitive: Bool, multi_line: Bool) }
Constructors
-
Options(case_insensitive: Bool, multi_line: Bool)
Regex
pub external type Regex
Functions
check
pub external fn check(with: Regex, content: String) -> Bool
Returns a boolean indicating whether there was a match or not.
Examples
> assert Ok(re) = from_string("^f.o.?")
> check(with: re, content: "foo")
True
> check(with: re, content: "boo")
False
compile
pub external fn compile( String, with: Options, ) -> Result(Regex, CompileError)
Create a Regex with some additional options.
Examples
> let options = Options(case_insensitive: False, multi_line: True)
> assert Ok(re) = compile("^[0-9]", with: options)
> match(re, "abc\n123")
True
> let options = Options(case_insensitive: True, multi_line: False)
> assert Ok(re) = compile("[A-Z]", with: options)
> match(re, "abc123")
True
from_string
pub fn from_string( pattern: String, ) -> Result(Regex, CompileError)
Create a new Regex.
Examples
> assert Ok(re) = from_string("[0-9]")
> match(re, "abc123")
True
> match(re, "abcxyz")
False
> from_string("[0-9")
Error(
CompileError(
error: "missing terminating ] for character class",
byte_index: 4
)
)
scan
pub external fn scan(with: Regex, content: String) -> List(Match)
Collects all matches of the regular expression.
Examples
> assert Ok(re) = regex.from_string("[oi]n a (\\w+)")
> regex.scan(with: re, content: "I am on a boat in a lake.")
[
Match(
content: "on a boat",
byte_index: 5,
submatches: [Some("boat")]
),
Match(
content: "in a lake",
byte_index: 15,
submatches: [Some("lake")]
)
]
split
pub external fn split( with: Regex, content: String, ) -> List(String)
Split a string
Examples
> assert Ok(re) = from_string(" *, *")
> split(with: re, content: "foo,32, 4, 9 ,0")
["foo", "32", "4", "9", "0"]