jass-lib jass-lib is a library for parsing and analyzing the JASS scripting language.
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checker Syntax syntax verifier syntax checker jass library JASS

jass-lib Description

jass-lib is a library for parsing and analyzing the JASS scripting language. jass-lib is a library for parsing and analyzing the JASS scripting language, which used for scripting Maps and AI files in Blizzard Entertainment's Warcraft III.Building:1) Install a Java Development Kit (J2SE). Windows users can get one from Sun Microsystems (http://java.sun.com). Mac users will have one if they install Apple's developer tools.2) Install some basic UNIX tools. Mac OS X users will already have them available with Apple's developer tools. Windows users are encouraged to use Cygwin (http://www.cygwin.com). At a minimum you need a bourne shell (sh), GNU make, sed, cd, ls, mkdir, cp, rm, tar, zip, and possibly others. Perl is required for running tests.3) Enter the top level directory JassLib/. Type:makeThis will build all the Java class files in src/.4) To build the Demo JASS Syntax Checker, type:make demo-win32for the windows version andmake demo-macfor the Mac OS X version. This will also create lib/jass.jar, which is a JAR archive of all the required classes.API Usage:If you wish to use the syntax checking API in your own Java program, buildjass.jar as described above. Then look at the classjass.api.SyntaxAnalyzer for how to use the basic API. You can usejass.demo.DemoChecker as an example. When you run your program, youneed to include jass.jar and jcup.jar in the classpath.Implementation Notes:If you browse through the jass.syntax package, you will probably observe that the syntax analyzer goes to an unnecessary amount of trouble (and hence the code is a bit bloated). For example, the analyzer strictly goes through three distinct phases: lexical analysis (tokenizing), parsing (grammar analysis -- construction of an abstract syntax tree), and semantic analysis (type checking and analyzing the AST). These three steps are usually required for a lanuage with a context free grammar and forward references. Because I "reverse engineered" the JASS language as I wrote the analyzer, I didn't know until I finished that forward references are illegal in JASS. Hence, analysis can really be done in one pass.If I were to start over (or if you were to write a parser), here are the design improvements I would make based on the JASS language's features:· Forget about writing a grammar for the entire input stream. Instead, after tokenizing the stream treat each line individually (grammars that are not free form and delimited by newlines are ugly). All lines are trivially checked by manual examination except for expressions. Just write a grammar for expressions and delegate the stream to the parser when you need to check an expression. As a bonus, this allows you to make error messages for some syntax errors more meaningful.· Do semantic analysis in the same pass that you parse. Because there can not be forward references, you don't have to worry about stuff that hasn't been parsed yet. This is faster and memory efficient since you don't have to build an AST (you can check each expression's tree on the fly as you parse it). You still do need to keep around a symbol table for variables and function names (and a type tree for handle types) obviously. Also, since you don't have to keep an AST around, memory management is much simpler.· Parse individual files separately. There is a wierd ordering of certain global declarations that has to be maintained within each file, but not among all files (which makes sense since there isn't really an "include" or "import" method). Just keep around the symbol table and type tree after you parse the library files like common.j.· Don't use a global (i.e., "static") symbol table. This ugly design hack exists in my code because I derived it from one of UC Berkeley's undergrad compiler project templates. Design so you can easily "export" the symbol table and type tree to a stream (e.g., file) and import it back -- this way you can "precompile" the library files like common.j and only have to load the symbol table and type tree instead of having to re-parse it every time.Of course, these suggestions are for an analyzer that is built for speed; it is not very flexible and would be difficult to adapt if a major change were made to the JASS language (e.g., forward references). Obviously, also write it in C or C++. Java, Perl, VB, etc. are for prototyping -- this is the prototype.

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