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/no or 1/yes)
                   - $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. (All settings can be used by local programs run
        directly by the user.)

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

METHODS