NAME

String::Utils - Provide some optimized string functions

SYNOPSIS

use String::Utils;

say before("foobar","bar");            # foo

say between("foobarbaz","foo","baz");  # bar

say between-included("foobarbaz","oo","baz");  # oobarbaz

say around("foobarbaz", "ob", "rb");   # foaz

say after("foobar","foo");             # bar

say chomp-needle("foobarbaz", "baz");  # foobar

say root <abcd abce abde>;             # ab

say leaf <zip.txt zop.txt ff.txt>;     # .txt

say is-sha1 "foo bar baz";             # False

say stem "foo.tar.gz";                 # foo
say stem "foo.tar.gz", 1;              # foo.tar

say ngram "foobar", 3;                 # foo oob oba bar

say non-word "foobar";                 # False
say non-word "foo/bar";                # True

say letters("//foo:bar");              # foobar

say nomark("élève");                   # eleve

say has-marks("foo👩🏽‍💻bar");             # False
say has-marks("fóöbar");               # True

dd leading-whitespace(" \t foo");      # " \t "
dd trailing-whitespace("bar \t ");     # " \t "
say is-whitespace("\t \n");            # True
say is-whitespace("\ta\n");            # False
say is-whitespace("");                 # True

say is-uppercase("FOOBAR");            # True
say is-uppercase("FooBar");            # False
say is-uppercase("");                  # True

say is-lowercase("foobar");            # True
say is-lowercase("FooBar");            # False
say is-lowercase("");                  # True

say consists-of("aaabbcc", "abc");     # True
say consists-of("aaadbcc", "abc");     # False
say consists-of("", "abc");            # True

say all-same("aaaaaa");                # "a"
say all-same("aaaaba");                # Nil
say all-same("");                      # Nil

.say for paragraphs("a\n\nb");         # 0 => a␤2 => b␤
.say for paragraphs($path.IO.lines);   # …

my $string = "foo";
my $regex  = regexify($string, :ignorecase);
say "FOOBAR" ~~ $regex;                # ｢FOO｣

dd expand-tab("a\tbb\tccc",4);         # "a   bb  ccc"

use String::Utils <before after>;  # only import "before" and "after"

DESCRIPTION

String::Utils provides some simple string functions that are not (yet) provided by the core Raku Programming Language.

These functions are implemented without using regexes for speed.

SELECTIVE IMPORTING

use String::Utils <before after>;  # only import "before" and "after"

By default all utility functions are exported. But you can limit this to the functions you actually need by specifying the names in the use statement.

To prevent name collisions and/or import any subroutine with a more memorable name, one can use the "original-name:known-as" syntax. A semi-colon in a specified string indicates the name by which the subroutine is known in this distribution, followed by the name with which it will be known in the lexical context in which the use command is executed.

use String::Utils <root:common-start>;  # import "root" as "common-start"

say common-start <abcd abce abde>;  # ab

SUBROUTINES

after

say after("foobar","foo");   # bar

say "foobar".&after("foo");  # bar

say after("foobar","goo");   # Nil

Return the string after a given string, or Nil if the given string could not be found. The equivalent of the stringification of / <?after foo> .* /.

around

say around("foobarbaz","ob","rb");     # foaz

say "foobarbaz".&around("ob","rb");    # foaz

say around("foobarbaz","goo","baz");   # foobarbaz

Return the string around two given strings, or the string itself if either of the bounding strings could not be found. The equivalent of .subst: / <?after ob> .*? <?before rb> /.

before

say before("foobar","bar");   # foo

say "foobar".&before("bar");  # foo

say before("foobar","baz");   # Nil

Return the string before a given string, or Nil if the given string could not be found. The equivalent of the stringification of / .*? <?before bar> /.

between

say between("foobarbaz","foo","baz");   # bar

say "foobarbaz".&between("foo","baz");  # bar

say between("foobarbaz","goo","baz");   # Nil

Return the string between two given strings, or Nil if either of the bounding strings could not be found. The equivalent of the stringification of / <?after foo> .*? <?before baz> /.

between-included

say between-included("foobarbaz","oo","baz");   # oobarbaz

say "foobarbaz".&between-included("oo","baz");  # oobarbaz

say between-included("foobarbaz","goo","baz");  # Nil

Return the string between two given strings including the given strings, or Nil if either of the bounding strings could not be found. The equivalent of the stringification of / o .*? baz /.

chomp-needle

say chomp-needle("foobarbaz","baz");   # foobar

say "foobarbaz".&chomp-needle("baz");  # foobar

say chomp-needle("foobarbaz","bar");   # foobarbaz

Return the string without the given target string at the end, or the string itself if the target string is not at the end. The equivalent of .subst(/ baz $/).

root

say root <abcd abce abde>;  # ab

Return the common beginning of the given strings, or the empty string if no common string could be found. See also leaf.

leaf

say leaf <zip.txt zop.txt ff.txt>;  # .txt

Return the common end of the given strings, or the empty string if no common string could be found. See also root.

is-sha1

say is-sha1 "abcd abce abde";  # False
say is-sha1 "356A192B7913B04C54574D18C28D46E6395428AB";  # True

Return a Bool indicating whether the given string is a SHA1 string (40 chars and only containing 0123456789ABCDEF).

stem

say stem "foo.tar.gz";     # foo
say stem "foo.tar.gz", 1;  # foo.tar
say stem "foo.tar.gz", *;  # foo

Return the stem of a string with all of its extensions removed. Optionally accepts a second argument indicating the number of extensions to be removed. This may be * (aka Whatever) to indicate to remove all extensions.

ngram

say ngram "foobar", 3;            # foo oob oba bar

say ngram "foobar", 4, :partial;  # foob ooba obar bar ar r

Return a sequence of substrings of the given size, while only moving up one position at a time in the original string. Optionally takes a :partial flag to also produce incomplete substrings at the end of the sequence.

non-word

say non-word "foobar";   # False

say non-word "foo/bar";  # True

Returns a Bool indicating whether the string contained any non-word characters.

letters

say letters("//foo:bar");  # foobar

Returns all of the alphanumeric characters in the given string as a string.

nomark

say nomark("élève");  # eleve

Returns the given string with any diacritcs removed.

has-marks

say has-marks("foo👩🏽‍💻bar");             # False
say has-marks("fóöbar");               # True

Returns a Bool indicating whether the given string contains any alphanumeric characters with marks (accents).

leading-whitespace

dd leading-whitespace("foo");      # ""
dd leading-whitespace(" \t foo");  # " \t "
dd leading-whitespace(" \t ");     # " \t "

Returns a Str containing any leading whitespace of the given string.

trailing-whitespace

dd trailing-whitespace("bar");      # ""
dd trailing-whitespace("bar \t ");  # " \t "
dd trailing-whitespace(" \t ");     # " \t "

Returns a Str containing any trailing whitespace of the given string.

is-whitespace

say is-whitespace("\t \n");  # True
say is-whitespace("\ta\n");  # False
say is-whitespace("");       # True

Returns a Bool indicating whether the string consists of just whitespace characters, or is empty.

is-uppercase

say is-uppercase("FOOBAR");  # True
say is-uppercase("FooBar");  # False
say is-uppercase("");        # True

Returns a Bool indicating whether the string consists of just uppercase characters, or is empty.

is-lowercase

say is-lowercase("foobar");  # True
say is-lowercase("FooBar");  # False
say is-lowercase("");        # True

Returns a Bool indicating whether the string consists of just lowercase characters, or is empty.

consists-of

say consists-of("aaabbcc", "abc");     # True
say consists-of("aaadbcc", "abc");     # False
say consists-of("", "abc");            # True

Returns a Bool indicating whether the string given as the first positional argument only consists of characters given as the second positional argument, or is empty.

all-same

say all-same("aaaaaa");                # "a"
say all-same("aaaaba");                # Nil
say all-same("");                      # Nil

If the given string consists of a single character, returns that character. Else returns Nil.

paragraphs

.say for paragraphs($path.IO.lines);   # …
.say for paragraphs("a\n\nb");         # 0 => a␤2 => b␤
.say for paragraphs("a\n\nb", 1);      # 1 => a␤3 => b␤

Lazily produces a Seq of Pairs with paragraphs from a Seq or string in which the key is the line number where the paragraph starts, and the value is the paragraph (without last trailing newline).

The optional second argument can be used to indicate the ordinal number of the first line in the string.

my class A is Pair { }
.say for paragraphs("a\n\nb", 1, :Pair(A));  # 1 => a␤␤3 => b␤

Also takes an optional named argument :Pair that indicates the class with which the objects should be created. This defailts to the core Pair class.

regexify

my $string = "foo";
my $regex  = regexify($string, :ignorecase);
say "FOOBAR" ~~ $regex;  # ｢FOO｣

Produce a Regex object from a given string and modifiers. Note that this is similar to the / <$string> / syntax. But opposed to that syntax, which interpolates the contents of the string each time the regex is executed, the Regex object returned by regexify is immutable.

The following modifiers are supported:

i / ignorecase

# accept haystack if "bar" is found, regardless of case
my $regex = regexify("bar", :i);  # or :ignorecase

Allow characters to match even if they are of mixed case.

smartcase

# accept haystack if "bar" is found, regardless of case
my &anycase = regexify("bar", :smartcase);

# accept haystack if "Bar" is found
my &exactcase = regexify("Bar", :smartcase);

If the needle is a string and does not contain any uppercase characters, then ignorecase semantics will be assumed.

m / ignoremark

# accept haystack if "bar" is found, regardless of any accents
my &anycase = regexify("bar", :m);  # or :ignoremark

Allow characters to match even if they have accents (or not).

smartmark

# accept haystack if "bar" is found, regardless of any accents
my &anymark = regexify("bar", :smartmark);

# accept haystack if "bår" is found
my &exactmark = regexify("bår", :smartmark);

If the needle is a string and does not contain any characters with accents, then ignoremark semantics will be assumed.

expand-tab

dd expand-tab("a\tbb\tccc",4);  # "a   bb  ccc"

Expand any tabs in a string (the first argument) to the given tab width (the second argument). If there are no tabs, then the given string will be returned unaltered.

If the tab width is zero or negative, will remove any tabs from the string. If the tab width is one, then all tabs will be replaced by spaces.

AUTHOR

Elizabeth Mattijsen liz@raku.rocks

Source can be located at: https://github.com/lizmat/String-Utils . Comments and Pull Requests are welcome.

If you like this module, or what I’m doing more generally, committing to a small sponsorship would mean a great deal to me!

COPYRIGHT AND LICENSE

Copyright 2022, 2023, 2024 Elizabeth Mattijsen

This library is free software; you can redistribute it and/or modify it under the Artistic License 2.0.