Brackets - the language of a BCC: generation

Welcome to []. The express purpose of this language is to provide MS Outlook with "Active Content" in mail headers. The idea comes from the habit of the members of the esolang news group to encode all their subjects in square brackets and put them in the header, although it can be quite difficult to do so when the subjects are still alive.

Features

Can read the Subject: line from news files. In fact, it must read this line, because code cannot be placed anywhere else but the subject line of a news file.
Gives spammers the chance of providing interactive spam. The world has been waiting for this !!!
Uses only brackets as commands: []{}()<>, everything else is considered data
The language model is, of course, reminisent of the great VAX assembler, the only assembler that can be sung.

Code model

The code model is very simple, and looks like a small assembler:

MoveXtoY:                   ({<<x]y)
AddXtoY:                    ({[<x]y)
SubXFromY:                  ({{<x]y)
MultiplyXWithY:             ({}<x]y)
DivideXWithY:               ([(<x]y)
CompareXAndY:               (]<<x]y)
NandXToY:                   (}[<x]y)
GotoLabelXIfNotEqual:       (((<x)
GotoLabelX:                 ((<<x)
DeclareLabelX:              (([<x)
PrintX:                     (({<x)
ClearX:                     ((}<x)
NegateX:                    ({(<x)
ImmediateX:                 ((<x>
RegisterXIndirect:          (<<x>
RegisterXIndirectIncrement: ([<x>
RegisterXIndirectDecrement: ({<x>
GotoLabelXIfEqual:          (}<x]
RegisterX:                  (<x>
DeclareDataX:               [x}

Here is a typical [] code:

Subject: <>(()[Brackets])<()0)}())[)()0))(]])1)
         <>>([)0)>[0]{(]()2)()))([)0))([])1)(]])2)

Code model

The [] source is a beauty to behold, if I may say so myself. You can browse it online. You can download the whole package here.