======Spam Filter Rules: Variables======
The VPOP3 spam filter script language supports simple variables. In most places these are specified as **${''<variable name>''}**, but in some places they are just specified as ''<variable name>'' - for instance where a statement always puts its result into a variable.

All variables are typeless, so the same variable can contain either a text or a number, and conversion between the two types will take place automatically as required. Arrays of variables are not supported.

The variable name is case insensitive, so **${MailFrom}** and **${mailfrom}** refer to the same variable.

=====Built-in variables=====
VPOP3 has several built-in variables which can be treated like any other:
^ Variable name ^Description ^Version ^
^${MailFrom}  |The SMTP return address of the message |2.1.7+ |
^${RcptCount}  |The number of recipients which VPOP3 knows about (from the SMTP envelope or recognised addresses in the message header) |2.1.7+ |
^${SenderIP}  |The sender's IP address (for SMTP mail only) |2.1.7+ |
^${Subject}  |The subject of the message |2.1.7+ |
^${MatchedConditions}  |A list of the currently matched rules |2.1.7+ |
^${Size}  |The raw size of the message |2.1.11+ |
^${AttachmentCount}  |The number of attachments in the message |2.1.11+ |
^${InlineAttachmentCount}  |The number of 'inline' attachments in the message (eg inline images etc) |2.1.11+ |
^${VPOP3Build}  |The currently running 'build number' of VPOP3 - you can find this on the **About** (previously **Info**) page in the VPOP3 settings |2.2.1+ |
^${WeightBank}  |The current values to use for a particular rule - see [[spamrules_statement_definerule|DefineRule]] |2.2.1+ |
^${RegExMatches}  |The number of regular expression matches from the last match expression |2.2.1+ |
^${''<n>''}  |e.g. **${1}** - The result of the previous regular expression match corresponding to the specified number. e.g. **${0}** gives the full string which matched the previous regular expression, **${1}** gives the string which matched the first parenthesised expression in the previous regular expression, and so on.|2.2.1+ |
^${Weight_''<name>''}  |The currently configured weight for a particular setting |2.2.1+ |
^${DNSServers}  |The DNS servers to use for DNS lookups |2.3.0+ |
^${BayesSize}  |The number of messages the Bayesian database covers |2.3.0+ |
^${SectionCheckSize}  |The maximum size of a message section to check (default is 50,000) |2.3.9+ |
^${CanChangeCheckSize}  |Returns '1' if this version of VPOP3 allows the script to change the **${SectionCheckSize}** value |2.3.11+ |
^${AuthSender}  |Returns the authenticated sender's username if the message is received using SMTP |2.4.5+ |
^${AnyInvalidRecipients}  |Returns '1' if any recipients of the message are non-existent local users |2.4.7+ |
^${VPOP3Version}  |The current VPOP3 version number (eg "6.15") |6.0 |
^${BATV} | Whether BATV is used (SMTP msgs only) 0 or 1 |6.15 |
^${SPFResult} | SPF test result (SMTP msgs only) |6.15 |
^${DKIMResult} | DKIM test result (SMTP msgs only) |6.15 |
^${SMTPHelo} | SMTP Helo String (SMTP msgs only) |6.15 |
^${SMTPReverseDNS} | Reverse DNS of SMTP client (SMTP msgs only) |6.15 |
^${DMARCResult} | Result of DMARC test (SMTP only) - pass,fail,temperror,permerror | 7.8 |
^${DMARCDisposition} | Policy result of DMARC (SMTP only) - none, reject, quarantine | 7.8 |
^${DMARCDomain} | Policy domain of DMARC (SMTP ony) | 7.8 |
^${TimeNow} | Time now in ISO-8601 (Zulu) format | 8.6 |
^${TimeNowDays} | Time now in fractional days since 1st Jan 1601 | 8.6 |
^${RFC822TimeNow} | Time now in RFC 822 Date header format | 8.6 |
=====Bags=====
The VPOP3 spam filter script language also supports 'Bags' which can contain collections of data. See [[spamrules_statement_addbag|AddBag]], [[spamrules_statement_removebag|RemoveBag]], [[spamrules_statement_ifinbag|IfInBag]], [[spamrules_statement_foreach|ForEach Bag]] and [[spamrules_statement_clearbag|ClearBag]]. 

'Bags' are similar to "Arrays" or "Sets" in other languages in that they can store multiple items of data, however the data cannot be accessed individually, you can use **ForEach Bag** to iterate through the data, or **IfInBag** to check if a specific item exists in the data.