Implementing The Compiler Of UDLC Based On Grid

As the complexity of chemical problems increasing, Chemical Research often requires many chemical software working together to complete. Most chemical software using its own script languages to describe jobs which are different to the others. For example the GJF files of Gaussian, the SPL files of SYBYL and the MOP files of Mopac. So in order to use computer to help the research, chemists have to learn to use these scripts before work. Unified Job-Description Language on Chemical Grid(UDLC) is aimed to solve this point. It's designed to provide a general-purpose standard for description language of chemical job. Using this standard to describe job would reduce the cost of chemical research. Many heterogeneous chemical resources integrated in the grid can be directly invoked using UDLC.In this article, we decide to talk about the two aspect in the whole process of how to design a DSL language like UDLC. The first aspect is:How to design the syntax of the language. In this aspect, we give the language requirement analysis and design the syntax of the language according to the requirement. At the end of this part, we give a simple example of UDLC. In the second aspect, we focus on the three main parts in implementing the compiler of UDLC. Firstly, how to build the Abstract Syntax tree (AST) for UDLC base on ANTLR. The AST is an intermediate form, it not only records the UDLC input symbols, also, the relationship between the symbols can be remembered using the father-son nodes and sibling nodes. By traverse the AST, we can get the symbols out conveniently and build them up to information. Secondly, semantic process. In this part, we map the AST into CML files and then search the CML with the help of DOM4J to get out the information. The information will be built to several chemical scripts. Lastly, build the final JAVA code. In order to do this, we have to traverse the AST again to extract the flow control sentences and insert the jobs into it. After these three steps, the JAVA code will be created and can be executed on the grid.