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String::Color - map strings to a color code


use String::Color;
use Randomcolor;                # some module for randomly generating colors

my $sc = String::Color.new(
  generator => { Randomcolor.new.list.head },
  cleaner   => { .lc },         # optionally provide own cleaning logic
  colors    => %colors-so-far,  # optionally start with given set

my @added = $sc.add(@nicks);    # add mapping for strings in @nicks

my %colors := $sc.Map;          # set up Map with color mappings so far

say "$color is already used"
  if $sc.known($color);        # check if a color is used already


String::Color provides a class and logic to map strings to a (random) color code. It does so by matching the cleaned version of a string.

The way a color is generated, is determined by the required generator named argument: it should provice a Callable that will take a cleaned string, and return a color for it.

The way a string is cleaned, can be specified with the optional cleaner named argument: it should provide a Callable that will take the string, and return a cleaned version of it. By default, the cleaning logic will remove any non-alpha characters, and lowercase the resulting string.

Strings can be continuously added by calling the add method. The current state can be obtained with the Map method. The known method can be used to see whether a color is already being used or not.

Note that colors are described as strings. In whichever format you would like. Technically, this module could be used to match strings to other strings that would not necessarily correspond to colors. But that's entirely up to the fantasy of the user of this module.

Also note that by e.g. writing out the Map of a String::Color object as e.g. JSON to disk, and then later use that in the colors argument to new, would effectively make the mapping persistent.

Finally, even though this may look like a normal hash, but all operations are thread safe (although results may be out of date).



my $sc = String::Color.new(
  generator => -> $string {
      $string eq 'liz'
        ?? "ff0000"
        !! RandomColor.new.list.head
  cleaner => { .lc },         # optionally provide own cleaning logic
  colors  => %colors-so-far,  # optionally start with given set

The new class method takes two named arguments.


The cleaner named argument allows one to specify a Callable which is supposed to take a string, and return a cleaned version of the string. By default, a cleaner that will remove all non-alpha characters and return the resulting string in lowercase, will be used.


The colors named argument allows one to specify a Hash / Map with colors that have been assigned to strings so far. Only the empty string mapping to the empty string will be assumed, if not specified.


The generator named argument specifies a Callable that will be called to generate a colors for the associated string (which gets passed to the Callable). It must be specified.



my @added = $sc.add(@strings);

The add instance method allows adding of strings to the colors mapping. It takes a list of strings as the positional argument. It returns a list of strings that were actually added (in the order they were added).


my @aliases = $sc.aliases($string);

The aliases instance method returns a sorted list of strings that are considered aliases of the given string, because they share the same cleaned string.


.say for $sc.cleaned;

The cleaned instance method returns the cleaned strings in the same order as strings.


say "colors assigned:";
.say for $sc.colors.unique;

The colors instance method returns the colors in the same order as strings.


say "$sc.elems() mappings so far";

The elems instance method returns the number of mappings.


say "$color is already used"
  if $sc.known($color);            # check if a color is used already

The known instance method takes a single string for color, and returns whether that color is already in use or not.


my %colors := $sc.Map;            # create simple Associative interface

The Map instance method returns the state of the mapping as a Map object, which can be bound to create an Associative interface. Or it can be used to create a persistent version of the mapping.


say "strings mapped:";
.say for $sc.strings;

The strings instance method returns the strings.


Elizabeth Mattijsen liz@raku.rocks

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


Copyright 2021 Elizabeth Mattijsen

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