###############################################################################
#
#   Package: NaturalDocs::Topics
#
###############################################################################
#
#   The topic constants and functions to convert them to and from strings used throughout the script.  All constants are exported
#   by default.
#
###############################################################################

# This file is part of Natural Docs, which is Copyright (C) 2003-2008 Greg Valure
# Natural Docs is licensed under the GPL

use Text::Wrap ( );
use Tie::RefHash ( );

use strict;
use integer;

use NaturalDocs::Topics::Type;

package NaturalDocs::Topics;

use base 'Exporter';
our @EXPORT = ( 'TOPIC_GENERAL', 'TOPIC_GENERIC', 'TOPIC_GROUP', 'TOPIC_CLASS', 'TOPIC_FILE', 'TOPIC_FUNCTION',
                          'TOPIC_VARIABLE', 'TOPIC_PROPERTY', 'TOPIC_TYPE', 'TOPIC_ENUMERATION', 'TOPIC_CONSTANT',
                          'TOPIC_INTERFACE', 'TOPIC_EVENT', 'TOPIC_DELEGATE', 'TOPIC_SECTION' );



###############################################################################
# Group: Types


#
#   Type: TopicType
#
#   A string representing a topic type as defined in <Topics.txt>.  It's format should be treated as opaque; use <MakeTopicType()>
#   to get them from topic names.  However, they can be compared for equality with string functions.
#


#
#   Constants: Default TopicTypes
#
#   Exported constants of the default <TopicTypes>, so you don't have to go through <TypeFromName()> every time.
#
#   TOPIC_GENERAL - The general <TopicType>, which has the special meaning of none in particular.
#   TOPIC_GENERIC - Generic <TopicType>.
#   TOPIC_GROUP - Group <TopicType>.
#   TOPIC_CLASS - Class <TopicType>.
#   TOPIC_INTERFACE - Interface <TopicType>.
#   TOPIC_FILE - File <TopicType>.
#   TOPIC_SECTION - Section <TopicType>.
#   TOPIC_FUNCTION - Function <TopicType>.
#   TOPIC_VARIABLE - Variable <TopicType>.
#   TOPIC_PROPERTY - Property <TopicType>.
#   TOPIC_TYPE - Type <TopicType>.
#   TOPIC_CONSTANT - Constant <TopicType>.
#   TOPIC_ENUMERATION - Enum <TopicType>.
#   TOPIC_DELEGATE - Delegate <TopicType>.
#   TOPIC_EVENT - Event <TopicType>.
#
use constant TOPIC_GENERAL => 'general';
use constant TOPIC_GENERIC => 'generic';
use constant TOPIC_GROUP => 'group';
use constant TOPIC_CLASS => 'class';
use constant TOPIC_INTERFACE => 'interface';
use constant TOPIC_FILE => 'file';
use constant TOPIC_SECTION => 'section';
use constant TOPIC_FUNCTION => 'function';
use constant TOPIC_VARIABLE => 'variable';
use constant TOPIC_PROPERTY => 'property';
use constant TOPIC_TYPE => 'type';
use constant TOPIC_CONSTANT => 'constant';
use constant TOPIC_ENUMERATION => 'enumeration';
use constant TOPIC_DELEGATE => 'delegate';
use constant TOPIC_EVENT => 'event';
# Dependency: The values of these constants must match what is generated by MakeTopicType().
# Dependency: These types must be added to requiredTypeNames so that they always exist.




###############################################################################
# Group: Variables


#
#   handle: FH_TOPICS
#
#   The file handle used when writing to <Topics.txt>.
#


#
#   hash: types
#
#   A hashref that maps <TopicTypes> to <NaturalDocs::Topics::Type>s.
#
my %types;


#
#   hash: names
#
#   A hashref that maps various forms of the all-lowercase type names to <TopicTypes>.  All are in the same hash because
#   two names that reduce to the same thing it would cause big problems, and we need to catch that.  Keys include
#
#   - Topic names
#   - Plural topic names
#   - Alphanumeric-only topic names
#   - Alphanumeric-only plural topic names
#
my %names;


#
#   hash: keywords
#
#   A hashref that maps all-lowercase keywords to their <TopicTypes>.  Must not have any of the same keys as
#   <pluralKeywords>.
#
my %keywords;


#
#   hash: pluralKeywords
#
#   A hashref that maps all-lowercase plural keywords to their <TopicTypes>.  Must not have any of the same keys as
#   <keywords>.
#
my %pluralKeywords;


#
#   hash: indexable
#
#   An existence hash of all the indexable <TopicTypes>.
#
my %indexable;


#
#   array: requiredTypeNames
#
#   An array of the <TopicType> names which are required to be defined in the main file.  Are in the order they should appear
#   when reformatting.
#
my @requiredTypeNames = ( 'Generic', 'Class', 'Interface', 'Section', 'File', 'Group', 'Function', 'Variable', 'Property', 'Type',
                                           'Constant', 'Enumeration', 'Event', 'Delegate' );


#
#   array: legacyTypes
#
#   An array that converts the legacy topic types, which were numeric constants prior to 1.3, to the current <TopicTypes>.
#   The legacy types are used as an index into the array.  Note that this does not support list type values.
#
my @legacyTypes = ( TOPIC_GENERAL, TOPIC_CLASS, TOPIC_SECTION, TOPIC_FILE, TOPIC_GROUP, TOPIC_FUNCTION,
                                TOPIC_VARIABLE, TOPIC_GENERIC, TOPIC_TYPE, TOPIC_CONSTANT, TOPIC_PROPERTY );


#
#   array: mainTopicNames
#
#   An array of the <TopicType> names that are defined in the main <Topics.txt>.
#
my @mainTopicNames;



###############################################################################
# Group: Files


#
#   File: Topics.txt
#
#   The configuration file that defines or overrides the topic definitions for Natural Docs.  One version sits in Natural Docs'
#   configuration directory, and another can be in a project directory to add to or override them.
#
#   > # [comments]
#
#   Everything after a # symbol is ignored.
#
#   Except when specifying topic names, everything below is case-insensitive.
#
#   > Format: [version]
#
#   Specifies the file format version of the file.
#
#
#   Sections:
#
#       > Ignore[d] Keyword[s]: [keyword], [keyword] ...
#       >    [keyword]
#       >    [keyword], [keyword]
#       >    ...
#
#       Ignores the keywords so that they're not recognized as Natural Docs topics anymore.  Can be specified as a list on the same
#       line and/or following like a normal Keywords section.
#
#       > Topic Type: [name]
#       > Alter Topic Type: [name]
#
#       Creates a new topic type or alters an existing one.  The name can only contain <CFChars> and isn't case sensitive, although
#       the original case is remembered for presentation.
#
#       The name General is reserved.  There are a number of default types that must be defined in the main file as well, but those
#       are governed by <NaturalDocs::Topics> and are not included here.  The default types can have their keywords or behaviors
#       changed, though, either by editing the default file or by overriding them in the user file.
#
#       Enumeration is a special type.  It is indexed with Types and its definition list members are listed with Constants according
#       to the rules in <Languages.txt>.
#
#
#   Topic Type Sections:
#
#       > Plural: [name]
#
#       Specifies the plural name of the topic type.  Defaults to the singular name.  Has the same restrictions as the topic type
#       name.
#
#       > Index: [yes|no]
#
#       Whether the topic type gets an index.  Defaults to yes.
#
#       > Scope: [normal|start|end|always global]
#
#       How the topic affects scope.  Defaults to normal.
#
#       normal - The topic stays within the current scope.
#       start - The topic starts a new scope for all the topics beneath it, like class topics.
#       end - The topic resets the scope back to global for all the topics beneath it, like section topics.
#       always global - The topic is defined as a global symbol, but does not change the scope for any other topics.
#
#       > Class Hierarchy: [yes|no]
#
#       Whether the topic is part of the class hierarchy.  Defaults to no.
#
#       > Page Title if First: [yes|no]
#
#       Whether the title of this topic becomes the page title if it is the first topic in a file.  Defaults to no.
#
#       > Break Lists: [yes|no]
#
#       Whether list topics should be broken into individual topics in the output.  Defaults to no.
#
#       > Can Group With: [topic type], [topic type], ...
#
#       The list of <TopicTypes> the topic can possibly be grouped with.
#
#       > [Add] Keyword[s]:
#       >    [keyword]
#       >    [keyword], [plural keyword]
#       >    ...
#
#       A list of the topic type's keywords.  Each line after the heading is the keyword and optionally its plural form.  This continues
#       until the next line in "keyword: value" format.  "Add" isn't required.
#
#       - Keywords can only have letters and numbers.  No punctuation or spaces are allowed.
#       - Keywords are not case sensitive.
#       - Subsequent keyword sections add to the list.  They don't replace it.
#       - Keywords can be redefined by other keyword sections.
#
#
#   Revisions:
#
#       1.3:
#
#           The initial version of this file.
#


###############################################################################
# Group: File Functions


#
#   Function: Load
#
#   Loads both the master and the project version of <Topics.txt>.
#
sub Load
    {
    my $self = shift;

    # Add the special General topic type.

    $types{::TOPIC_GENERAL()} = NaturalDocs::Topics::Type->New('General', 'General', 1, ::SCOPE_NORMAL(), undef);
    $names{'general'} = ::TOPIC_GENERAL();
    $indexable{::TOPIC_GENERAL()} = 1;
    # There are no keywords for the general topic.


    $self->LoadFile(1);  # Main

    # Dependency: All the default topic types must be checked for existence.

    # Check to see if the required types are defined.
    foreach my $name (@requiredTypeNames)
        {
        if (!exists $names{lc($name)})
            {  NaturalDocs::ConfigFile->AddError('The ' . $name . ' topic type must be defined in the main topics file.');  };
        };

    my $errorCount = NaturalDocs::ConfigFile->ErrorCount();

    if ($errorCount)
        {
        NaturalDocs::ConfigFile->PrintErrorsAndAnnotateFile();
        NaturalDocs::Error->SoftDeath('There ' . ($errorCount == 1 ? 'is an error' : 'are ' . $errorCount . ' errors')
                                                    . ' in ' . NaturalDocs::Project->MainConfigFile('Topics.txt'));
        }


    $self->LoadFile();  # User

    $errorCount = NaturalDocs::ConfigFile->ErrorCount();

    if ($errorCount)
        {
        NaturalDocs::ConfigFile->PrintErrorsAndAnnotateFile();
        NaturalDocs::Error->SoftDeath('There ' . ($errorCount == 1 ? 'is an error' : 'are ' . $errorCount . ' errors')
                                                    . ' in ' . NaturalDocs::Project->UserConfigFile('Topics.txt'));
        }
    };


#
#   Function: LoadFile
#
#   Loads a particular version of <Topics.txt>.
#
#   Parameters:
#
#       isMain - Whether the file is the main file or not.
#
sub LoadFile #(isMain)
    {
    my ($self, $isMain) = @_;

    my ($file, $status);

    if ($isMain)
        {
        $file = NaturalDocs::Project->MainConfigFile('Topics.txt');
        $status = NaturalDocs::Project->MainConfigFileStatus('Topics.txt');
        }
    else
        {
        $file = NaturalDocs::Project->UserConfigFile('Topics.txt');
        $status = NaturalDocs::Project->UserConfigFileStatus('Topics.txt');
        };

    my $version;

    if ($version = NaturalDocs::ConfigFile->Open($file))
        {
        # The format hasn't changed since the file was introduced.

        if ($status == ::FILE_CHANGED())
            {  NaturalDocs::Project->ReparseEverything();  };

        my ($topicTypeKeyword, $topicTypeName, $topicType, $topicTypeObject, $inKeywords, $inIgnoredKeywords);

        # Keys are topic type objects, values are unparsed strings.
        my %canGroupWith;
        tie %canGroupWith, 'Tie::RefHash';

        while (my ($keyword, $value) = NaturalDocs::ConfigFile->GetLine())
            {
            if ($keyword)
                {
                $inKeywords = 0;
                $inIgnoredKeywords = 0;
                };

            if ($keyword eq 'topic type')
                {
                $topicTypeKeyword = $keyword;
                $topicTypeName = $value;

                # Resolve conflicts and create the type if necessary.

                $topicType = $self->MakeTopicType($topicTypeName);
                my $lcTopicTypeName = lc($topicTypeName);

                my $lcTopicTypeAName = $lcTopicTypeName;
                $lcTopicTypeAName =~ tr/a-z0-9//cd;

                if (!NaturalDocs::ConfigFile->HasOnlyCFChars($topicTypeName))
                    {
                    NaturalDocs::ConfigFile->AddError('Topic names can only have ' . NaturalDocs::ConfigFile->CFCharNames() . '.');
                    }
                elsif ($topicType eq ::TOPIC_GENERAL())
                    {
                    NaturalDocs::ConfigFile->AddError('You cannot define a General topic type.');
                    }
                elsif (defined $types{$topicType} || defined $names{$lcTopicTypeName} || defined $names{$lcTopicTypeAName})
                    {
                    NaturalDocs::ConfigFile->AddError('Topic type ' . $topicTypeName . ' is already defined or its name is too '
                                                                     . 'similar to an existing name.  Use Alter Topic Type if you meant to override '
                                                                     . 'its settings.');
                    }
                else
                    {
                    $topicTypeObject = NaturalDocs::Topics::Type->New($topicTypeName, $topicTypeName, 1, ::SCOPE_NORMAL(),
                                                                                                  0, 0);

                    $types{$topicType} = $topicTypeObject;
                    $names{$lcTopicTypeName} = $topicType;
                    $names{$lcTopicTypeAName} = $topicType;

                    $indexable{$topicType} = 1;

                    if ($isMain)
                        {  push @mainTopicNames, $topicTypeName;  };
                    };
                }

            elsif ($keyword eq 'alter topic type')
                {
                $topicTypeKeyword = $keyword;
                $topicTypeName = $value;

                # Resolve conflicts and create the type if necessary.

                $topicType = $names{lc($topicTypeName)};

                if (!defined $topicType)
                    {  NaturalDocs::ConfigFile->AddError('Topic type ' . $topicTypeName . ' doesn\'t exist.');  }
                elsif ($topicType eq ::TOPIC_GENERAL())
                    {  NaturalDocs::ConfigFile->AddError('You cannot alter the General topic type.');  }
                else
                    {
                    $topicTypeObject = $types{$topicType};
                    };
                }

            elsif ($keyword =~ /^ignored? keywords?$/)
                {
                $inIgnoredKeywords = 1;

                my @ignoredKeywords = split(/ ?, ?/, lc($value));

                foreach my $ignoredKeyword (@ignoredKeywords)
                    {
                    delete $keywords{$ignoredKeyword};
                    delete $pluralKeywords{$ignoredKeyword};
                    };
                }

            # We continue even if there are errors in the topic type line so that we can find any other errors in the file as well.  We'd
            # rather them all show up at once instead of them showing up one at a time between Natural Docs runs.  So we just ignore
            # the settings if $topicTypeObject is undef.


            elsif ($keyword eq 'plural')
                {
                my $pluralName = $value;
                my $lcPluralName = lc($pluralName);

                my $lcPluralAName = $lcPluralName;
                $lcPluralAName =~ tr/a-zA-Z0-9//cd;

                if (!NaturalDocs::ConfigFile->HasOnlyCFChars($pluralName))
                    {
                    NaturalDocs::ConfigFile->AddError('Plural names can only have '
                                                                     . NaturalDocs::ConfigFile->CFCharNames() . '.');
                    }
                elsif ($lcPluralAName eq 'general')
                    {
                    NaturalDocs::ConfigFile->AddError('You cannot use General as a plural name for ' . $topicTypeName . '.');
                    }
                elsif ( (defined $names{$lcPluralName} && $names{$lcPluralName} ne $topicType) ||
                         (defined $names{$lcPluralAName} && $names{$lcPluralAName} ne $topicType) )
                    {
                    NaturalDocs::ConfigFile->AddError($topicTypeName . "'s plural name, " . $pluralName
                                                                     . ', is already defined or is too similar to an existing name.');
                    }

                elsif (defined $topicTypeObject)
                    {
                    $topicTypeObject->SetPluralName($pluralName);

                    $names{$lcPluralName} = $topicType;
                    $names{$lcPluralAName} = $topicType;
                    };
                }

            elsif ($keyword eq 'index')
                {
                $value = lc($value);

                if ($value eq 'yes')
                    {
                    if (defined $topicTypeObject)
                        {
                        $topicTypeObject->SetIndex(1);
                        $indexable{$topicType} = 1;
                        };
                    }
                elsif ($value eq 'no')
                    {
                    if (defined $topicTypeObject)
                        {
                        $topicTypeObject->SetIndex(0);
                        delete $indexable{$topicType};
                        };
                    }
                else
                    {
                    NaturalDocs::ConfigFile->AddError('Index lines can only be "yes" or "no".');
                    };
                }

            elsif ($keyword eq 'class hierarchy')
                {
                $value = lc($value);

                if ($value eq 'yes')
                    {
                    if (defined $topicTypeObject)
                        {  $topicTypeObject->SetClassHierarchy(1);  };
                    }
                elsif ($value eq 'no')
                    {
                    if (defined $topicTypeObject)
                        {  $topicTypeObject->SetClassHierarchy(0);  };
                    }
                else
                    {
                    NaturalDocs::ConfigFile->AddError('Class Hierarchy lines can only be "yes" or "no".');
                    };
                }

            elsif ($keyword eq 'scope')
                {
                $value = lc($value);

                if ($value eq 'normal')
                    {
                    if (defined $topicTypeObject)
                        {  $topicTypeObject->SetScope(::SCOPE_NORMAL());  };
                    }
                elsif ($value eq 'start')
                    {
                    if (defined $topicTypeObject)
                        {  $topicTypeObject->SetScope(::SCOPE_START());  };
                    }
                elsif ($value eq 'end')
                    {
                    if (defined $topicTypeObject)
                        {  $topicTypeObject->SetScope(::SCOPE_END());  };
                    }
                elsif ($value eq 'always global')
                    {
                    if (defined $topicTypeObject)
                        {  $topicTypeObject->SetScope(::SCOPE_ALWAYS_GLOBAL());  };
                    }
                else
                    {
                    NaturalDocs::ConfigFile->AddError('Scope lines can only be "normal", "start", "end", or "always global".');
                    };
                }

            elsif ($keyword eq 'page title if first')
                {
                $value = lc($value);

                if ($value eq 'yes')
                    {
                    if (defined $topicTypeObject)
                        {  $topicTypeObject->SetPageTitleIfFirst(1);  };
                    }
                elsif ($value eq 'no')
                    {
                    if (defined $topicTypeObject)
                        {  $topicTypeObject->SetPageTitleIfFirst(undef);  };
                    }
                else
                    {
                    NaturalDocs::ConfigFile->AddError('Page Title if First lines can only be "yes" or "no".');
                    };
                }

            elsif ($keyword eq 'break lists')
                {
                $value = lc($value);

                if ($value eq 'yes')
                    {
                    if (defined $topicTypeObject)
                        {  $topicTypeObject->SetBreakLists(1);  };
                    }
                elsif ($value eq 'no')
                    {
                    if (defined $topicTypeObject)
                        {  $topicTypeObject->SetBreakLists(undef);  };
                    }
                else
                    {
                    NaturalDocs::ConfigFile->AddError('Break Lists lines can only be "yes" or "no".');
                    };
                }

            elsif ($keyword eq 'can group with')
                {
                if (defined $topicTypeObject)
                    {  $canGroupWith{$topicTypeObject} = lc($value);  };
                }

            elsif ($keyword =~ /^(?:add )?keywords?$/)
                {
                $inKeywords = 1;
                }

            elsif (defined $keyword)
                {  NaturalDocs::ConfigFile->AddError($keyword . ' is not a valid keyword.');  }

            elsif (!$inKeywords && !$inIgnoredKeywords)
                {
                NaturalDocs::ConfigFile->AddError('All lines in ' . $topicTypeKeyword . ' sections must begin with a keyword.');
                }

            else # No keyword but in keyword section.
                {
                $value = lc($value);

                if ($value =~ /^([a-z0-9 ]*[a-z0-9]) ?, ?([a-z0-9 ]+)$/)
                    {
                    my ($singular, $plural) = ($1, $2);

                    if ($inIgnoredKeywords)
                        {
                        delete $keywords{$singular};
                        delete $keywords{$plural};
                        delete $pluralKeywords{$singular};
                        delete $pluralKeywords{$plural};
                        }
                    elsif (defined $topicTypeObject)
                        {
                        $keywords{$singular} = $topicType;
                        delete $pluralKeywords{$singular};

                        $pluralKeywords{$plural} = $topicType;
                        delete $keywords{$plural};
                        };
                    }
                elsif ($value =~ /^[a-z0-9 ]+$/)
                    {
                    if ($inIgnoredKeywords)
                        {
                        delete $keywords{$value};
                        delete $pluralKeywords{$value};
                        }
                    elsif (defined $topicType)
                        {
                        $keywords{$value} = $topicType;
                        delete $pluralKeywords{$value};
                        };
                    }
                else
                    {
                    NaturalDocs::ConfigFile->AddError('Keywords can only have letters, numbers, and spaces.  '
                                                                     . 'Plurals must be separated by a comma.');
                    };
                };
            };

        NaturalDocs::ConfigFile->Close();


        # Parse out the Can Group With lines now that everything's defined.

        while (my ($typeObject, $value) = each %canGroupWith)
            {
            my @values = split(/ ?, ?/, $value);
            my @types;

            foreach my $value (@values)
                {
                # We're just going to ignore invalid items.
                if (exists $names{$value})
                    {  push @types, $names{$value};  };
                };

            if (scalar @types)
                {  $typeObject->SetCanGroupWith(\@types);  };
            };
        }

    else # couldn't open file
        {
        if ($isMain)
            {  die "Couldn't open topics file " . $file . "\n";  }
        else
            {  NaturalDocs::Project->ReparseEverything();  };
        };
    };


#
#   Function: Save
#
#   Saves the main and user versions of <Topics.txt>.
#
sub Save
    {
    my $self = shift;

    $self->SaveFile(1); # Main
    $self->SaveFile(0); # User
    };


#
#   Function: SaveFile
#
#   Saves a particular version of <Topics.txt>.
#
#   Parameters:
#
#       isMain - Whether the file is the main file or not.
#
sub SaveFile #(isMain)
    {
    my ($self, $isMain) = @_;

    my $file;

    if ($isMain)
        {
        if (NaturalDocs::Project->MainConfigFileStatus('Topics.txt') == ::FILE_SAME())
            {  return;  };
        $file = NaturalDocs::Project->MainConfigFile('Topics.txt');
        }
    else
        {
        # We have to check the main one two because this lists the topics defined in it.
        if (NaturalDocs::Project->UserConfigFileStatus('Topics.txt') == ::FILE_SAME() &&
            NaturalDocs::Project->MainConfigFileStatus('Topics.txt') == ::FILE_SAME())
            {  return;  };
        $file = NaturalDocs::Project->UserConfigFile('Topics.txt');
        };


    # Array of topic type names in the order they appear in the file.  If Alter Topic Type is used, the name will end with an asterisk.
    my @topicTypeOrder;

    # Keys are topic type names, values are property hashrefs.  Hashref keys are the property names, values the value.
    # For keywords, the key is Keywords and the values are arrayrefs of singular and plural pairs.  If no plural is defined, the entry
    # will be undef.
    my %properties;

    # List of ignored keywords specified as Ignore Keywords: [keyword], [keyword], ...
    my @inlineIgnoredKeywords;

    # List of ignored keywords specified in [keyword], [plural keyword] lines.  Done in pairs, like for regular keywords.
    my @separateIgnoredKeywords;

    my $inIgnoredKeywords;

    if (NaturalDocs::ConfigFile->Open($file))
        {
        # We can assume the file is valid.

        my ($keyword, $value, $topicTypeName);

        while (($keyword, $value) = NaturalDocs::ConfigFile->GetLine())
            {
            $keyword = lc($keyword);

            if ($keyword eq 'topic type' || $keyword eq 'alter topic type')
                {
                $topicTypeName = $types{ $names{lc($value)} }->Name();

                if ($keyword eq 'alter topic type')
                    {  $topicTypeName .= '*';  };

                push @topicTypeOrder, $topicTypeName;

                if (!exists $properties{$topicTypeName})
                    {  $properties{$topicTypeName} = { 'keywords' => [ ] };  };
                }

            elsif ($keyword eq 'plural')
                {
                $properties{$topicTypeName}->{$keyword} = $value;
                }

            elsif ($keyword eq 'index' ||
                    $keyword eq 'scope' ||
                    $keyword eq 'page title if first' ||
                    $keyword eq 'class hierarchy' ||
                    $keyword eq 'break lists' ||
                    $keyword eq 'can group with')
                {
                $properties{$topicTypeName}->{$keyword} = lc($value);
                }

            elsif ($keyword =~ /^(?:add )?keywords?$/)
                {
                $inIgnoredKeywords = 0;
                }

            elsif ($keyword =~ /^ignored? keywords?$/)
                {
                $inIgnoredKeywords = 1;
                if ($value)
                    {  push @inlineIgnoredKeywords, split(/ ?, ?/, $value);  };
                }

            elsif (!$keyword)
                {
                my ($singular, $plural) = split(/ ?, ?/, lc($value));

                if ($inIgnoredKeywords)
                    {  push @separateIgnoredKeywords, $singular, $plural;  }
                else
                    {  push @{$properties{$topicTypeName}->{'keywords'}}, $singular, $plural;  };
                };
            };

        NaturalDocs::ConfigFile->Close();
        };


    if (!open(FH_TOPICS, '>' . $file))
        {
        # The main file may be on a shared volume or some other place the user doesn't have write access to.  Since this is only to
        # reformat the file, we can ignore the failure.
        if ($isMain)
            {  return;  }
        else
            {  die "Couldn't save " . $file;  };
        };

    print FH_TOPICS 'Format: ' . NaturalDocs::Settings->TextAppVersion() . "\n\n";

    # Remember the 80 character limit.

    if ($isMain)
        {
        print FH_TOPICS
        "# This is the main Natural Docs topics file.  If you change anything here, it\n"
        . "# will apply to EVERY PROJECT you use Natural Docs on.  If you'd like to\n"
        . "# change something for just one project, edit the Topics.txt in its project\n"
        . "# directory instead.\n";
        }
    else
        {
        print FH_TOPICS
        "# This is the Natural Docs topics file for this project.  If you change anything\n"
        . "# here, it will apply to THIS PROJECT ONLY.  If you'd like to change something\n"
        . "# for all your projects, edit the Topics.txt in Natural Docs' Config directory\n"
        . "# instead.\n\n\n";

        if (scalar @inlineIgnoredKeywords || scalar @separateIgnoredKeywords)
            {
            if (scalar @inlineIgnoredKeywords == 1 && !scalar @separateIgnoredKeywords)
                {
                print FH_TOPICS 'Ignore Keyword: ' . $inlineIgnoredKeywords[0] . "\n";
                }
            else
                {
                print FH_TOPICS
                'Ignore Keywords: ' . join(', ', @inlineIgnoredKeywords) . "\n";

                for (my $i = 0; $i < scalar @separateIgnoredKeywords; $i += 2)
                    {
                    print FH_TOPICS '   ' . $separateIgnoredKeywords[$i];

                    if (defined $separateIgnoredKeywords[$i + 1])
                        {  print FH_TOPICS ', ' . $separateIgnoredKeywords[$i + 1];  };

                    print FH_TOPICS "\n";
                    };
                };
            }
        else
            {
            print FH_TOPICS
            "# If you'd like to prevent keywords from being recognized by Natural Docs, you\n"
            . "# can do it like this:\n"
            . "# Ignore Keywords: [keyword], [keyword], ...\n"
            . "#\n"
            . "# Or you can use the list syntax like how they are defined:\n"
            . "# Ignore Keywords:\n"
            . "#    [keyword]\n"
            . "#    [keyword], [plural keyword]\n"
            . "#    ...\n";
            };
        };

    print FH_TOPICS # [CFChars]
    "\n\n"
    . "#-------------------------------------------------------------------------------\n"
    . "# SYNTAX:\n"
    . "#\n";

    if ($isMain)
        {
        print FH_TOPICS
        "# Topic Type: [name]\n"
        . "#    Creates a new topic type.  Each type gets its own index and behavior\n"
        . "#    settings.  Its name can have letters, numbers, spaces, and these\n"
        . "#    charaters: - / . '\n"
        . "#\n"
        . "#    The Enumeration type is special.  It's indexed with Types but its members\n"
        . "#    are indexed with Constants according to the rules in Languages.txt.\n"
        . "#\n"
        }
    else
        {
        print FH_TOPICS
        "# Topic Type: [name]\n"
        . "# Alter Topic Type: [name]\n"
        . "#    Creates a new topic type or alters one from the main file.  Each type gets\n"
        . "#    its own index and behavior settings.  Its name can have letters, numbers,\n"
        . "#    spaces, and these charaters: - / . '\n"
        . "#\n";
        };

    print FH_TOPICS
    "# Plural: [name]\n"
    . "#    Sets the plural name of the topic type, if different.\n"
    . "#\n"
    . "# Keywords:\n"
    . "#    [keyword]\n"
    . "#    [keyword], [plural keyword]\n"
    . "#    ...\n";

    if ($isMain)
        {
        print FH_TOPICS
        "#    Defines a list of keywords for the topic type.  They may only contain\n"
        . "#    letters, numbers, and spaces and are not case sensitive.  Plural keywords\n"
        . "#    are used for list topics.\n";
        }
    else
        {
        print FH_TOPICS
        "#    Defines or adds to the list of keywords for the topic type.  They may only\n"
        . "#    contain letters, numbers, and spaces and are not case sensitive.  Plural\n"
        . "#    keywords are used for list topics.  You can redefine keywords found in the\n"
        . "#    main topics file.\n";
        }

    print FH_TOPICS
    "#\n"
    . "# Index: [yes|no]\n"
    . "#    Whether the topics get their own index.  Defaults to yes.  Everything is\n"
    . "#    included in the general index regardless of this setting.\n"
    . "#\n"
    . "# Scope: [normal|start|end|always global]\n"
    . "#    How the topics affects scope.  Defaults to normal.\n"
    . "#    normal        - Topics stay within the current scope.\n"
    . "#    start         - Topics start a new scope for all the topics beneath it,\n"
    . "#                    like class topics.\n"
    . "#    end           - Topics reset the scope back to global for all the topics\n"
    . "#                    beneath it.\n"
    . "#    always global - Topics are defined as global, but do not change the scope\n"
    . "#                    for any other topics.\n"
    . "#\n"
    . "# Class Hierarchy: [yes|no]\n"
    . "#    Whether the topics are part of the class hierarchy.  Defaults to no.\n"
    . "#\n"
    . "# Page Title If First: [yes|no]\n"
    . "#    Whether the topic's title becomes the page title if it's the first one in\n"
    . "#    a file.  Defaults to no.\n"
    . "#\n"
    . "# Break Lists: [yes|no]\n"
    . "#    Whether list topics should be broken into individual topics in the output.\n"
    . "#    Defaults to no.\n"
    . "#\n"
    . "# Can Group With: [type], [type], ...\n"
    . "#    Defines a list of topic types that this one can possibly be grouped with.\n"
    . "#    Defaults to none.\n"
    . "#-------------------------------------------------------------------------------\n\n";

    my $listToPrint;

    if ($isMain)
        {
        print FH_TOPICS
        "# The following topics MUST be defined in this file:\n"
        . "#\n";
        $listToPrint = \@requiredTypeNames;
        }
    else
        {
        print FH_TOPICS
        "# The following topics are defined in the main file, if you'd like to alter\n"
        . "# their behavior or add keywords:\n"
        . "#\n";
        $listToPrint = \@mainTopicNames;
        }

    print FH_TOPICS
    Text::Wrap::wrap('#    ', '#    ', join(', ', @$listToPrint)) . "\n"
    . "\n"
    . "# If you add something that you think would be useful to other developers\n"
    . "# and should be included in Natural Docs by default, please e-mail it to\n"
    . "# topics [at] naturaldocs [dot] org.\n";

    # Existence hash.  We do this because we want the required ones to go first by adding them to @topicTypeOrder, but we don't
    # want them to appear twice.
    my %doneTopicTypes;
    my ($altering, $numberOfProperties);

    if ($isMain)
        {  unshift @topicTypeOrder, @requiredTypeNames;  };

    my @propertyOrder = ('Plural', 'Index', 'Scope', 'Class Hierarchy', 'Page Title If First', 'Break Lists');

    foreach my $topicType (@topicTypeOrder)
        {
        if (!exists $doneTopicTypes{$topicType})
            {
            if (substr($topicType, -1) eq '*')
                {
                print FH_TOPICS "\n\n"
                . 'Alter Topic Type: ' . substr($topicType, 0, -1) . "\n\n";

                $altering = 1;
                $numberOfProperties = 0;
                }
            else
                {
                print FH_TOPICS "\n\n"
                . 'Topic Type: ' . $topicType . "\n\n";

                $altering = 0;
                $numberOfProperties = 0;
                };

            foreach my $property (@propertyOrder)
                {
                if (exists $properties{$topicType}->{lc($property)})
                    {
                    print FH_TOPICS
                    '   ' . $property . ': ' . ucfirst( $properties{$topicType}->{lc($property)} ) . "\n";

                    $numberOfProperties++;
                    };
                };

            if (exists $properties{$topicType}->{'can group with'})
                {
                my @typeStrings = split(/ ?, ?/, lc($properties{$topicType}->{'can group with'}));
                my @types;

                foreach my $typeString (@typeStrings)
                    {
                    if (exists $names{$typeString})
                        {  push @types, $names{$typeString};  };
                    };

                if (scalar @types)
                    {
                    for (my $i = 0; $i < scalar @types; $i++)
                        {
                        my $name = NaturalDocs::Topics->NameOfType($types[$i], 1);

                        if ($i == 0)
                            {  print FH_TOPICS '   Can Group With: ' . $name;  }
                        else
                            {  print FH_TOPICS ', ' . $name;  };
                        };

                    print FH_TOPICS "\n";
                    $numberOfProperties++;
                    };
                };

            if (scalar @{$properties{$topicType}->{'keywords'}})
                {
                if ($numberOfProperties > 1)
                    {  print FH_TOPICS "\n";  };

                print FH_TOPICS
                '   ' . ($altering ? 'Add ' : '') . 'Keywords:' . "\n";

                my $keywords = $properties{$topicType}->{'keywords'};

                for (my $i = 0; $i < scalar @$keywords; $i += 2)
                    {
                    print FH_TOPICS '      ' . $keywords->[$i];

                    if (defined $keywords->[$i + 1])
                        {  print FH_TOPICS ', ' . $keywords->[$i + 1];  };

                    print FH_TOPICS "\n";
                    };
                };

            $doneTopicTypes{$topicType} = 1;
            };
        };

    close(FH_TOPICS);
    };



###############################################################################
# Group: Functions


#
#   Function: KeywordInfo
#
#   Returns information about a topic keyword.
#
#   Parameters:
#
#       keyword - The keyword, which may be plural.
#
#   Returns:
#
#       The array ( topicType, info, isPlural ), or an empty array if the keyword doesn't exist.
#
#       topicType - The <TopicType> of the keyword.
#       info - The <NaturalDocs::Topics::Type> of its type.
#       isPlural - Whether the keyword was plural or not.
#
sub KeywordInfo #(keyword)
    {
    my ($self, $keyword) = @_;

    $keyword = lc($keyword);

    my $type = $keywords{$keyword};

    if (defined $type)
        {  return ( $type, $types{$type}, undef );  };

    $type = $pluralKeywords{$keyword};

    if (defined $type)
        {  return ( $type, $types{$type}, 1 );  };

    return ( );
    };


#
#   Function: NameInfo
#
#   Returns information about a topic name.
#
#   Parameters:
#
#      name - The topic type name, which can be plural and/or alphanumeric only.
#
#   Returns:
#
#       The array ( topicType, info ), or an empty array if the name doesn't exist.  Note that unlike <KeywordInfo()>, this
#       does *not* tell you whether the name is plural or not.
#
#       topicType - The <TopicType> of the name.
#       info - The <NaturalDocs::Topics::Type> of the type.
#
sub NameInfo #(name)
    {
    my ($self, $name) = @_;

    my $type = $names{lc($name)};

    if (defined $type)
        {  return ( $type, $types{$type} );  }
    else
        {  return ( );  };
    };


#
#   Function: TypeInfo
#
#   Returns information about a <TopicType>.
#
#   Parameters:
#
#      type - The <TopicType>.
#
#   Returns:
#
#       The <NaturalDocs::Topics::Type> of the type, or undef if it didn't exist.
#
sub TypeInfo #(type)
    {
    my ($self, $type) = @_;
    return $types{$type};
    };


#
#   Function: NameOfType
#
#   Returns the name of the passed <TopicType>, or undef if it doesn't exist.
#
#   Parameters:
#
#       topicType - The <TopicType>.
#       plural - Whether to return the plural instead of the singular.
#       alphanumericOnly - Whether to strips everything but alphanumeric characters out.  Case isn't modified.
#
#   Returns:
#
#       The topic type name, according to what was specified in the parameters, or undef if it doesn't exist.
#
sub NameOfType #(topicType, plural, alphanumericOnly)
    {
    my ($self, $topicType, $plural, $alphanumericOnly) = @_;

    my $topicObject = $types{$topicType};

    if (!defined $topicObject)
        {  return undef;  };

    my $topicName = ($plural ? $topicObject->PluralName() : $topicObject->Name());

    if ($alphanumericOnly)
        {  $topicName =~ tr/a-zA-Z0-9//cd;  };

    return $topicName;
    };


#
#   Function: TypeFromName
#
#   Returns a <TopicType> for the passed topic name.
#
#   Parameters:
#
#       topicName - The name of the topic, which can be plural and/or alphanumeric only.
#
#   Returns:
#
#       The <TopicType>.  It does not specify whether the name was plural or not.
#
sub TypeFromName #(topicName)
    {
    my ($self, $topicName) = @_;

    return $names{lc($topicName)};
    };


#
#   Function: IsValidType
#
#   Returns whether the passed <TopicType> is defined.
#
sub IsValidType #(type)
    {
    my ($self, $type) = @_;
    return exists $types{$type};
    };


#
#   Function: TypeFromLegacy
#
#   Returns a <TopicType> for the passed legacy topic type integer.  <TopicTypes> were changed from integer constants to
#   strings in 1.3.
#
sub TypeFromLegacy #(legacyInt)
    {
    my ($self, $int) = @_;
    return $legacyTypes[$int];
    };


#
#   Function: AllIndexableTypes
#
#   Returns an array of all possible indexable <TopicTypes>.
#
sub AllIndexableTypes
    {
    my ($self) = @_;
    return keys %indexable;
    };



###############################################################################
# Group: Support Functions


#
#   Function: MakeTopicType
#
#   Returns a <TopicType> for the passed topic name.  It does not check to see if it exists already.
#
#   Parameters:
#
sub MakeTopicType #(topicName)
    {
    my ($self, $topicName) = @_;

    # Dependency: The values of the default topic type constants must match what is generated here.

    # Turn everything to lowercase and strip non-alphanumeric characters.
    $topicName = lc($topicName);
    $topicName =~ tr/a-z0-9//cd;

    return $topicName;
    };



1;