"rock", "stone", "mist", "random"

        "rock", "stone", "mist", "shimmer_blue", "random"

void game_options::add_all(const std::string &s, const std::string &separator,
                           void (game_options::*add)(const std::string &))

void game_options::split_parse(
    const std::string &s, const std::string &separator,
    void (game_options::*add)(const std::string &))

void game_options::set_option_fragment(const std::string &s)
{
    if (s.empty())
        return;
    
    std::string::size_type st = s.find(':');
    if (st == std::string::npos)
    {
        // Boolean option.
        if (s[0] == '!')
            read_option_line(s.substr(1) + " = false");
        else
            read_option_line(s + " = true");
    }
    else
    {
        // key:val option.
        read_option_line(s.substr(0, st) + " = " + s.substr(st + 1));
    }
}

        && key != "mon_glyph"

        && key != "mon_glyph" && key != "opt" && key != "option"

    // everything not a valid line is treated as a comment
    if (key == "autopickup")

    if (key == "opt" || key == "option")
    {
        split_parse(field, ",", &game_options::set_option_fragment);
    }
    else if (key == "autopickup")

        add_all(field, ";", &game_options::add_feature_override);

        split_parse(field, ";", &game_options::add_feature_override);

        add_all(field, ",", &game_options::add_mon_glyph_override);

        split_parse(field, ",", &game_options::add_mon_glyph_override);

    void add_all(const std::string &s, const std::string &separator,
                 void (game_options::*add)(const std::string &));

    void split_parse(const std::string &s, const std::string &separator,
                     void (game_options::*add)(const std::string &));

    void set_option_fragment(const std::string &s);    

There are basically three types of Crawl options: true/false values (booleans),
numbers, and lists. An option is most often specified with its default value 
(if there is one); this should also explain which of the above-mentioned types 
it is. Each option should have some remarks on how it's typically used - beware
that this depends strongly on your playing style and sometimes also on hardware
or operating system.

There are three broad types of Crawl options: true/false values
(booleans), arbitrary values, and lists of values. In this document,
options are usually described with their default values (if there is a
default); this should also explain which of the above-mentioned types
it is. Each option should have some remarks on how it's typically used
- but keep in mind that the options you want to use depend on your
playing style and sometimes also on your operating system.

Note that the init.txt coming with regular distributions has all boolean 
options commented out. The commented-out values are always the _non-defaults_, 
so you can toggle boolean options by just uncommenting them.

The standard init.txt distributed with Crawl includes all boolean
options, commented out. The commented-out values are always the
_non-defaults_, so you can toggle boolean options by uncommenting
them.

Some options need a path as an argument; here you have to use a filesystem path
suitable for your system. Other options accept regular expressions (regexes):
here you can simply use ordinary strings, adapt the suggested regexes to your
needs or search the internet for regex syntax.

There are two styles you can use to set options. The classic
name=value syntax, one option per-line:
    remember_name  = true
    explore_greedy = false
    drop_mode      = multi
And the NetHack-style combined option line:
    OPTION = remember_name, !explore_greedy, drop_mode:multi
The second style is useful to specify simple options in a few lines,
but it cannot be used for options that take complex lists of values
(such as the autopickup_exceptions option).
Some options need a path as an argument; here you have to use a
filesystem path suitable for your system. Other options accept regular
expressions (regexes): here you can simply use ordinary strings, adapt
the suggested regexes to your needs or search the internet for regex
syntax.