fn_dice_parse

CREATE FUNCTION public.fn_dice_parse(dice text) RETURNS TABLE(rolls integer, die integer, modifier integer, result integer)
    LANGUAGE plpgsql
    AS $_$
declare
    parsed text[];
begin
    parsed := regexp_matches(dice, '^\s*(\d+)d(\d+)([+-]\d+)?\s*$');
    rolls := parsed[1]::integer;
    die := parsed[2]::integer;
    modifier := parsed[3]::integer;
    if (rolls is null and die is null and modifier is null) then
        parsed := regexp_matches(dice, '^\s*([+-]?\d+)\s*$');
        modifier := parsed[1]::integer;
        result := modifier;
        if (modifier is null) then
            return;
        end if;
    else
        if (modifier is null) then
            result := 0;
        else
            result := modifier;
        end if;
        if (rolls > 0 and die > 0) then
            for i in 1..rolls loop
                result := result + floor(random() * die) + 1;
            end loop;
        end if;
    end if;
    return next;
end;
$_$;