NAME
    Mail::SpamAssassin::Conf::Parser - parse SpamAssassin configuration

SYNOPSIS
      (see Mail::SpamAssassin)

DESCRIPTION
    Mail::SpamAssassin is a module to identify spam using text analysis and
    several internet-based realtime blacklists.

    This class is used internally by SpamAssassin to parse its configuration
    files. Please refer to the "Mail::SpamAssassin" documentation for public
    interfaces.

STRUCTURE OF A CONFIG BLOCK
    This is the structure of a config-setting block. Each is a hashref which
    may contain these keys:

    setting
        the name of the setting it modifies, e.g. "required_score". this
        also doubles as the default for 'command' (below). THIS IS REQUIRED.

    command
        The command string used in the config file for this setting.
        Optional; 'setting' will be used for the command if this is omitted.

    aliases
        An [aryref] of other aliases for the same command. optional.

    type
        The type of this setting:

                   - $CONF_TYPE_STRING: string
                   - $CONF_TYPE_NUMERIC: numeric value (float or int)
                   - $CONF_TYPE_BOOL: boolean (0 or 1)
                   - $CONF_TYPE_TEMPLATE: template, like "report"
                   - $CONF_TYPE_ADDRLIST: address list, like "whitelist_from"
                   - $CONF_TYPE_HASH_KEY_VALUE: hash key/value pair,
                     like "describe" or tflags

        If this is set, a 'code' block is assigned based on the type.

        Note that $CONF_TYPE_HASH_KEY_VALUE-type settings require that the
        value be non-empty, otherwise they'll produce a warning message.

    code
        A subroutine to deal with the setting. Only used if type is not set.
        ONE OF code OR type IS REQUIRED. The arguments passed to the
        function are "($self, $key, $value, $line)", where $key is the
        setting (*not* the command), $value is the value string, and $line
        is the entire line.

        There are two special return values that the code subroutine may
        return to signal that there is an error in the configuration:

        $Mail::SpamAssassin::Conf::MISSING_REQUIRED_VALUE -- this setting
        requires that a value be set, but one was not provided.

        $Mail::SpamAssassin::Conf::INVALID_VALUE -- this setting requires a
        value from a set of 'valid' values, but the user provided an invalid
        one.

        Any other values -- including "undef" -- returned from the
        subroutine are considered to mean 'success'.

    default
        The default value for the setting. may be omitted if the default
        value is a non-scalar type, which should be set in the Conf ctor.
        note for path types: using "__userstate__" is recommended for
        defaults, as it allows Mail::SpamAssassin module users who set that
        configuration setting, to receive the correct values.

    is_priv
        Set to 1 if this setting requires 'allow_user_rules' when run from
        spamd.

    is_admin
        Set to 1 if this setting can only be set in the system-wide config
        when run from spamd.

    is_frequent
        Set to 1 if this value occurs frequently in the config. this means
        it's looked up first for speed.

    Note that the registered commands array can be extended by plugins, by
    adding the new config settings to the "$conf-<gt"{registered_commands}>
    array ref.

METHODS