| /// \page buildrec How to build Generated C Code |
| /// |
| /// \section generated Generated Files |
| /// |
| /// The antlr tool jar, run against a grammar file that targets the C language, will generate the following files |
| /// according to whether your grammar file contains a lexer, parser, combined or treeparser specification. |
| /// Your grammar file name and the subject of the grammar line in your file are expected to match. Here the generic name G is used: |
| /// |
| /// <table> |
| /// <tr> |
| /// <th> Suffix </th> |
| /// <th> Generated files </th> |
| /// </tr> |
| /// <tr> |
| /// <td> lexer grammar (G.g3l) </td> |
| /// <td> GLexer.c GLexer.h</td> |
| /// </tr> |
| /// <tr> |
| /// <td> parser grammar (G.g3p) </td> |
| /// <td> GParser.c GParser.h </td> |
| /// </tr> |
| /// <tr> |
| /// <td> grammar G (G.g3pl) </td> |
| /// <td> GParser.c GParser.h GLexer.c GLexer.h</td> |
| /// </tr> |
| /// <tr> |
| /// <td> tree grammar G; (G.g3t) </td> |
| /// <td> G.c G.h </td> |
| /// </tr> |
| /// </table> |
| /// |
| /// The generated .c files reference the .h files using <G.h>, so you must use <code>-I.</code> on your compiler command line |
| /// (or include the current directory in your include paths in Visual Studio). Additionally, the generated .h files reference |
| /// <code>antlr3.h</code>, so you must use <code>-I/path/to/antlr/include</code> (E.g. <code>-I /usr/local/include</code>) to reference the standard ANTLR include files. |
| /// |
| /// In order to reference the library file at compile time (you can/should only reference one) you need to use the |
| /// <code>-L/path/to/antlr/lib</code> (E.g. <code>-L /usr/local/lib</code>) on Unix, or add the path to your "Additional Library Path" in |
| /// Visual Studio. You also need to specify the library using <code>-L</code> on Unix (E.g. <code>-L /usr/local/lib -l antlr3c</code>) or add <code>antlr3c_dll.lib</code> |
| /// to your Additional Library Dependencies in Visual Studio. |
| /// |
| /// In case it isn't obvious, the generated files may be used to produce either a library or an executable (.EXE on Windows) file. |
| /// |
| /// If you use the shared version of the libraries, DLL or .so/.so/.a then you must ship the library with your |
| /// application must run in an environment whereby the library can be found by the runtime linker/loader. |
| /// This usually involves specifying the directory in which the library lives to an environment variable. |
| /// On Windows, X:{yourwininstalldir}\system32 will be searched automatically. |
| /// |
| /// \section invoke Invoking Your Generated Recognizer |
| /// |
| /// In order to run your lexer/parser/tree parser combination, you will need a small function (or main) |
| /// function that controls the sequence of events, from reading the input file or string, through to |
| /// invoking the tree parser(s) and retrieving the results. See "Using the ANTLR3C C Target" for more |
| /// detailed instructions, but if you just want to get going as fast as possible, study the following |
| /// code example. |
| /// |
| /// \code |
| /// |
| /// // You may adopt your own practices by all means, but in general it is best |
| /// // to create a single include for your project, that will include the ANTLR3 C |
| /// // runtime header files, the generated header files (all of which are safe to include |
| /// // multiple times) and your own project related header files. Use <> to include and |
| /// // -I on the compile line (which vs2005 now handles, where vs2003 did not). |
| /// // |
| /// #include <treeparser.h> |
| /// |
| /// // Main entry point for this example |
| /// // |
| /// int ANTLR3_CDECL |
| /// main (int argc, char *argv[]) |
| /// { |
| /// // Now we declare the ANTLR related local variables we need. |
| /// // Note that unless you are convinced you will never need thread safe |
| /// // versions for your project, then you should always create such things |
| /// // as instance variables for each invocation. |
| /// // ------------------- |
| /// |
| /// // Name of the input file. Note that we always use the abstract type pANTLR3_UINT8 |
| /// // for ASCII/8 bit strings - the runtime library guarantees that this will be |
| /// // good on all platforms. This is a general rule - always use the ANTLR3 supplied |
| /// // typedefs for pointers/types/etc. |
| /// // |
| /// pANTLR3_UINT8 fName; |
| /// |
| /// // The ANTLR3 character input stream, which abstracts the input source such that |
| /// // it is easy to privide inpput from different sources such as files, or |
| /// // memory strings. |
| /// // |
| /// // For an 8Bit/latin-1/etc memory string use: |
| /// // input = antlr3New8BitStringInPlaceStream (stringtouse, (ANTLR3_UINT32) length, NULL); |
| /// // |
| /// // For a UTF16 memory string use: |
| /// // input = antlr3NewUTF16StringInPlaceStream (stringtouse, (ANTLR3_UINT32) length, NULL); |
| /// // |
| /// // For input from a file, see code below |
| /// // |
| /// // Note that this is essentially a pointer to a structure containing pointers to functions. |
| /// // You can create your own input stream type (copy one of the existing ones) and override any |
| /// // individual function by installing your own pointer after you have created the standard |
| /// // version. |
| /// // |
| /// pANTLR3_INPUT_STREAM input; |
| /// |
| /// // The lexer is of course generated by ANTLR, and so the lexer type is not upper case. |
| /// // The lexer is supplied with a pANTLR3_INPUT_STREAM from whence it consumes its |
| /// // input and generates a token stream as output. This is the ctx (CTX macro) pointer |
| /// // for your lexer. |
| /// // |
| /// pLangLexer lxr; |
| /// |
| /// // The token stream is produced by the ANTLR3 generated lexer. Again it is a structure based |
| /// // API/Object, which you can customise and override methods of as you wish. a Token stream is |
| /// // supplied to the generated parser, and you can write your own token stream and pass this in |
| /// // if you wish. |
| /// // |
| /// pANTLR3_COMMON_TOKEN_STREAM tstream; |
| /// |
| /// // The Lang parser is also generated by ANTLR and accepts a token stream as explained |
| /// // above. The token stream can be any source in fact, so long as it implements the |
| /// // ANTLR3_TOKEN_SOURCE interface. In this case the parser does not return anything |
| /// // but it can of course specify any kind of return type from the rule you invoke |
| /// // when calling it. This is the ctx (CTX macro) pointer for your parser. |
| /// // |
| /// pLangParser psr; |
| /// |
| /// // The parser produces an AST, which is returned as a member of the return type of |
| /// // the starting rule (any rule can start first of course). This is a generated type |
| /// // based upon the rule we start with. |
| /// // |
| /// LangParser_decl_return langAST; |
| /// |
| /// |
| /// // The tree nodes are managed by a tree adaptor, which doles |
| /// // out the nodes upon request. You can make your own tree types and adaptors |
| /// // and override the built in versions. See runtime source for details and |
| /// // eventually the wiki entry for the C target. |
| /// // |
| /// pANTLR3_COMMON_TREE_NODE_STREAM nodes; |
| /// |
| /// // Finally, when the parser runs, it will produce an AST that can be traversed by the |
| /// // the tree parser: c.f. LangDumpDecl.g3t This is the ctx (CTX macro) pointer for your |
| /// // tree parser. |
| /// // |
| /// pLangDumpDecl treePsr; |
| /// |
| /// // Create the input stream based upon the argument supplied to us on the command line |
| /// // for this example, the input will always default to ./input if there is no explicit |
| /// // argument. |
| /// // |
| /// if (argc < 2 || argv[1] == NULL) |
| /// { |
| /// fName =(pANTLR3_UINT8)"./input"; // Note in VS2005 debug, working directory must be configured |
| /// } |
| /// else |
| /// { |
| /// fName = (pANTLR3_UINT8)argv[1]; |
| /// } |
| /// |
| /// // Create the input stream using the supplied file name |
| /// // (Use antlr38BitFileStreamNew for UTF16 input). |
| /// // |
| /// input = antlr38BitFileStreamNew(fName); |
| /// |
| /// // The input will be created successfully, providing that there is enough |
| /// // memory and the file exists etc |
| /// // |
| /// if ( input == NULL ) |
| /// { |
| /// ANTLR3_FPRINTF(stderr, "Unable to open file %s due to malloc() failure1\n", (char *)fName); |
| /// } |
| /// |
| /// // Our input stream is now open and all set to go, so we can create a new instance of our |
| /// // lexer and set the lexer input to our input stream: |
| /// // (file | memory | ?) --> inputstream -> lexer --> tokenstream --> parser ( --> treeparser )? |
| /// // |
| /// lxr = LangLexerNew(input); // CLexerNew is generated by ANTLR |
| /// |
| /// // Need to check for errors |
| /// // |
| /// if ( lxr == NULL ) |
| /// { |
| /// ANTLR3_FPRINTF(stderr, "Unable to create the lexer due to malloc() failure1\n"); |
| /// exit(ANTLR3_ERR_NOMEM); |
| /// } |
| /// |
| /// // Our lexer is in place, so we can create the token stream from it |
| /// // NB: Nothing happens yet other than the file has been read. We are just |
| /// // connecting all these things together and they will be invoked when we |
| /// // call the parser rule. ANTLR3_SIZE_HINT can be left at the default usually |
| /// // unless you have a very large token stream/input. Each generated lexer |
| /// // provides a token source interface, which is the second argument to the |
| /// // token stream creator. |
| /// // Note tha even if you implement your own token structure, it will always |
| /// // contain a standard common token within it and this is the pointer that |
| /// // you pass around to everything else. A common token as a pointer within |
| /// // it that should point to your own outer token structure. |
| /// // |
| /// tstream = antlr3CommonTokenStreamSourceNew(ANTLR3_SIZE_HINT, lxr->pLexer->tokSource); |
| /// |
| /// if (tstream == NULL) |
| /// { |
| /// ANTLR3_FPRINTF(stderr, "Out of memory trying to allocate token stream\n"); |
| /// exit(ANTLR3_ERR_NOMEM); |
| /// } |
| /// |
| /// // Finally, now that we have our lexer constructed, we can create the parser |
| /// // |
| /// psr = LangParserNew(tstream); // CParserNew is generated by ANTLR3 |
| /// |
| /// if (psr == NULL) |
| /// { |
| /// ANTLR3_FPRINTF(stderr, "Out of memory trying to allocate parser\n"); |
| /// exit(ANTLR3_ERR_NOMEM); |
| /// } |
| /// |
| /// // We are all ready to go. Though that looked complicated at first glance, |
| /// // I am sure, you will see that in fact most of the code above is dealing |
| /// // with errors and there isn;t really that much to do (isn;t this always the |
| /// // case in C? ;-). |
| /// // |
| /// // So, we now invoke the parser. All elements of ANTLR3 generated C components |
| /// // as well as the ANTLR C runtime library itself are pseudo objects. This means |
| /// // that they are represented as pointers to structures, which contain any |
| /// // instance data they need, and a set of pointers to other interfaces or |
| /// // 'methods'. Note that in general, these few pointers we have created here are |
| /// // the only things you will ever explicitly free() as everything else is created |
| /// // via factories, that allocate memory efficiently and free() everything they use |
| /// // automatically when you close the parser/lexer/etc. |
| /// // |
| /// // Note that this means only that the methods are always called via the object |
| /// // pointer and the first argument to any method, is a pointer to the structure itself. |
| /// // It also has the side advantage, if you are using an IDE such as VS2005 that can do it |
| /// // that when you type ->, you will see a list of all the methods the object supports. |
| /// // |
| /// langAST = psr->decl(psr); |
| /// |
| /// // If the parser ran correctly, we will have a tree to parse. In general I recommend |
| /// // keeping your own flags as part of the error trapping, but here is how you can |
| /// // work out if there were errors if you are using the generic error messages |
| /// // |
| /// if (psr->pParser->rec->errorCount > 0) |
| /// { |
| /// ANTLR3_FPRINTF(stderr, "The parser returned %d errors, tree walking aborted.\n", psr->pParser->rec->errorCount); |
| /// |
| /// } |
| /// else |
| /// { |
| /// nodes = antlr3CommonTreeNodeStreamNewTree(langAST.tree, ANTLR3_SIZE_HINT); // sIZE HINT WILL SOON BE DEPRECATED!! |
| /// |
| /// // Tree parsers are given a common tree node stream (or your override) |
| /// // |
| /// treePsr = LangDumpDeclNew(nodes); |
| /// |
| /// treePsr->decl(treePsr); |
| /// nodes ->free (nodes); nodes = NULL; |
| /// treePsr ->free (treePsr); treePsr = NULL; |
| /// } |
| /// |
| /// // We did not return anything from this parser rule, so we can finish. It only remains |
| /// // to close down our open objects, in the reverse order we created them |
| /// // |
| /// psr ->free (psr); psr = NULL; |
| /// tstream ->free (tstream); tstream = NULL; |
| /// lxr ->free (lxr); lxr = NULL; |
| /// input ->close (input); input = NULL; |
| /// |
| /// return 0; |
| /// } |
| /// \endcode |
| /// |