Comments for Swarmites

MAML stands for Multi-Agent Modeling Language and it was initiated for agent-based modeling and simulation. In its current state, it is heavily based on Swarm functionalities, as its current compiler (xmc) generates Swarm (v1.02 or v1.3) code which can be compiled again using the appropriate (gcc) compiler.

The main goal of MAML is to provide the functionality of Swarm without the low-level (mostly C and/or Objective-C) technical burdain. To achieve it quickly, the current version of MAML defines a macro-language for Swarm. This macro-level programming introduces higher level concepts of modeling, and simplifies some constructs already included in Swarm by hiding out technical details needed to program them. The macro-language nature of MAML, however, preserves the accessibility of the whole Swarm machinery.

MAML has a special syntax which helped its implementation and also helps to differentiate between Swarm and MAML statements. This syntax however might seem a bit awkward in some cases, because is is somewhat verbose. The syntax was planned this way with future enhancements and MAML functionalities (another high-level concepts) in mind, and some 'verbose' statements are, in fact, only placeholders for future tools.

Actually, very few of the planned MAML constructs are included in this version. Most of the current MAML structures are simplified and clarified concepts from Swarm itself. For example, the concept of model has led to the MAML structure called @model (no submodels are supported in this first version yet). The model structure can be extended by an @observe structure, which builds upon the ideas introduced in Swarm. The main difference from Swarm, however, is that these two MAML structures allow for different MAML-keywords to be used within them, thus helping to separate the different functionalities.

Also, constructs usable in @observe-s allow for later extensions of the @model and the agents. This helps to avoid the conceptually messy current practice in Swarm, which while separates the model and the observer, forces the user to incorporate message handlers into the model and the agents - making the model's entities handle the queries of the observer.

To end this impromptu listing of major MAML constructs, some important 'syntactic sugar' must be noted. We have incorporated a mechanism to simplify the creation phase of agents (and objects), providing support for the creation of agent arrays too. This @create construct has proved to be a very powerful machinery.

Finally, as some keywords have been 'duplicated' (i.e., keywords very similar to those in C and Objective-C), we must quickly clarify their roles.

As with C and Objective-C compilers, the MAML compiler (xmc) also has two phases: the  preprocessor and the compiling phases. (Contact the reference manual for more details.) In the preprocessor phase the usual 'preprocessor directives' are available for MAML, too. These are the $define and $import constructs. While the syntax and, to some extent, the functionality of these structures are different from the usual C/Objective-C equivalents, the main purpose is the same. Note, however, that these constructs belong to the MAML compiler (xmc), and thus define-replacements and file-imports take place before the MAML-code is compiled, while on the other hand traditional (Objective-C) #imports and #defines only make their effects after the MAML-compilation. Therefore, definitions and imports intended for the MAML compiler should follow the $import / $define format.

Also, for the sake of simplicity, a MAML construct, @uses has been introduced, whose functionality is similar to that of #import in Objective-C. @uses, however, is preferable as it is conceptually clearer.