1 /// \page buildrec How to build Generated C Code 2 /// 3 /// \section generated Generated Files 4 /// 5 /// The antlr tool jar, run against a grammar file that targets the C language, will generate the following files 6 /// according to whether your grammar file contains a lexer, parser, combined or treeparser specification. 7 /// 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: 8 /// 9 /// <table> 10 /// <tr> 11 /// <th> Suffix </th> 12 /// <th> Generated files </th> 13 /// </tr> 14 /// <tr> 15 /// <td> lexer grammar (G.g3l) </td> 16 /// <td> GLexer.c GLexer.h</td> 17 /// </tr> 18 /// <tr> 19 /// <td> parser grammar (G.g3p) </td> 20 /// <td> GParser.c GParser.h </td> 21 /// </tr> 22 /// <tr> 23 /// <td> grammar G (G.g3pl) </td> 24 /// <td> GParser.c GParser.h GLexer.c GLexer.h</td> 25 /// </tr> 26 /// <tr> 27 /// <td> tree grammar G; (G.g3t) </td> 28 /// <td> G.c G.h </td> 29 /// </tr> 30 /// </table> 31 /// 32 /// The generated .c files reference the .h files using <G.h>, so you must use <code>-I.</code> on your compiler command line 33 /// (or include the current directory in your include paths in Visual Studio). Additionally, the generated .h files reference 34 /// <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. 35 /// 36 /// In order to reference the library file at compile time (you can/should only reference one) you need to use the 37 /// <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 38 /// 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> 39 /// to your Additional Library Dependencies in Visual Studio. 40 /// 41 /// In case it isn't obvious, the generated files may be used to produce either a library or an executable (.EXE on Windows) file. 42 /// 43 /// If you use the shared version of the libraries, DLL or .so/.so/.a then you must ship the library with your 44 /// application must run in an environment whereby the library can be found by the runtime linker/loader. 45 /// This usually involves specifying the directory in which the library lives to an environment variable. 46 /// On Windows, X:{yourwininstalldir}\system32 will be searched automatically. 47 /// 48 /// \section invoke Invoking Your Generated Recognizer 49 /// 50 /// In order to run your lexer/parser/tree parser combination, you will need a small function (or main) 51 /// function that controls the sequence of events, from reading the input file or string, through to 52 /// invoking the tree parser(s) and retrieving the results. See "Using the ANTLR3C C Target" for more 53 /// detailed instructions, but if you just want to get going as fast as possible, study the following 54 /// code example. 55 /// 56 /// \code 57 /// 58 /// // You may adopt your own practices by all means, but in general it is best 59 /// // to create a single include for your project, that will include the ANTLR3 C 60 /// // runtime header files, the generated header files (all of which are safe to include 61 /// // multiple times) and your own project related header files. Use <> to include and 62 /// // -I on the compile line (which vs2005 now handles, where vs2003 did not). 63 /// // 64 /// #include <treeparser.h> 65 /// 66 /// // Main entry point for this example 67 /// // 68 /// int ANTLR3_CDECL 69 /// main (int argc, char *argv[]) 70 /// { 71 /// // Now we declare the ANTLR related local variables we need. 72 /// // Note that unless you are convinced you will never need thread safe 73 /// // versions for your project, then you should always create such things 74 /// // as instance variables for each invocation. 75 /// // ------------------- 76 /// 77 /// // Name of the input file. Note that we always use the abstract type pANTLR3_UINT8 78 /// // for ASCII/8 bit strings - the runtime library guarantees that this will be 79 /// // good on all platforms. This is a general rule - always use the ANTLR3 supplied 80 /// // typedefs for pointers/types/etc. 81 /// // 82 /// pANTLR3_UINT8 fName; 83 /// 84 /// // The ANTLR3 character input stream, which abstracts the input source such that 85 /// // it is easy to privide inpput from different sources such as files, or 86 /// // memory strings. 87 /// // 88 /// // For an 8Bit/latin-1/etc memory string use: 89 /// // input = antlr3New8BitStringInPlaceStream (stringtouse, (ANTLR3_UINT32) length, NULL); 90 /// // 91 /// // For a UTF16 memory string use: 92 /// // input = antlr3NewUTF16StringInPlaceStream (stringtouse, (ANTLR3_UINT32) length, NULL); 93 /// // 94 /// // For input from a file, see code below 95 /// // 96 /// // Note that this is essentially a pointer to a structure containing pointers to functions. 97 /// // You can create your own input stream type (copy one of the existing ones) and override any 98 /// // individual function by installing your own pointer after you have created the standard 99 /// // version. 100 /// // 101 /// pANTLR3_INPUT_STREAM input; 102 /// 103 /// // The lexer is of course generated by ANTLR, and so the lexer type is not upper case. 104 /// // The lexer is supplied with a pANTLR3_INPUT_STREAM from whence it consumes its 105 /// // input and generates a token stream as output. This is the ctx (CTX macro) pointer 106 /// // for your lexer. 107 /// // 108 /// pLangLexer lxr; 109 /// 110 /// // The token stream is produced by the ANTLR3 generated lexer. Again it is a structure based 111 /// // API/Object, which you can customise and override methods of as you wish. a Token stream is 112 /// // supplied to the generated parser, and you can write your own token stream and pass this in 113 /// // if you wish. 114 /// // 115 /// pANTLR3_COMMON_TOKEN_STREAM tstream; 116 /// 117 /// // The Lang parser is also generated by ANTLR and accepts a token stream as explained 118 /// // above. The token stream can be any source in fact, so long as it implements the 119 /// // ANTLR3_TOKEN_SOURCE interface. In this case the parser does not return anything 120 /// // but it can of course specify any kind of return type from the rule you invoke 121 /// // when calling it. This is the ctx (CTX macro) pointer for your parser. 122 /// // 123 /// pLangParser psr; 124 /// 125 /// // The parser produces an AST, which is returned as a member of the return type of 126 /// // the starting rule (any rule can start first of course). This is a generated type 127 /// // based upon the rule we start with. 128 /// // 129 /// LangParser_decl_return langAST; 130 /// 131 /// 132 /// // The tree nodes are managed by a tree adaptor, which doles 133 /// // out the nodes upon request. You can make your own tree types and adaptors 134 /// // and override the built in versions. See runtime source for details and 135 /// // eventually the wiki entry for the C target. 136 /// // 137 /// pANTLR3_COMMON_TREE_NODE_STREAM nodes; 138 /// 139 /// // Finally, when the parser runs, it will produce an AST that can be traversed by the 140 /// // the tree parser: c.f. LangDumpDecl.g3t This is the ctx (CTX macro) pointer for your 141 /// // tree parser. 142 /// // 143 /// pLangDumpDecl treePsr; 144 /// 145 /// // Create the input stream based upon the argument supplied to us on the command line 146 /// // for this example, the input will always default to ./input if there is no explicit 147 /// // argument. 148 /// // 149 /// if (argc < 2 || argv[1] == NULL) 150 /// { 151 /// fName =(pANTLR3_UINT8)"./input"; // Note in VS2005 debug, working directory must be configured 152 /// } 153 /// else 154 /// { 155 /// fName = (pANTLR3_UINT8)argv[1]; 156 /// } 157 /// 158 /// // Create the input stream using the supplied file name 159 /// // (Use antlr38BitFileStreamNew for UTF16 input). 160 /// // 161 /// input = antlr38BitFileStreamNew(fName); 162 /// 163 /// // The input will be created successfully, providing that there is enough 164 /// // memory and the file exists etc 165 /// // 166 /// if ( input == NULL ) 167 /// { 168 /// ANTLR3_FPRINTF(stderr, "Unable to open file %s due to malloc() failure1\n", (char *)fName); 169 /// } 170 /// 171 /// // Our input stream is now open and all set to go, so we can create a new instance of our 172 /// // lexer and set the lexer input to our input stream: 173 /// // (file | memory | ?) --> inputstream -> lexer --> tokenstream --> parser ( --> treeparser )? 174 /// // 175 /// lxr = LangLexerNew(input); // CLexerNew is generated by ANTLR 176 /// 177 /// // Need to check for errors 178 /// // 179 /// if ( lxr == NULL ) 180 /// { 181 /// ANTLR3_FPRINTF(stderr, "Unable to create the lexer due to malloc() failure1\n"); 182 /// exit(ANTLR3_ERR_NOMEM); 183 /// } 184 /// 185 /// // Our lexer is in place, so we can create the token stream from it 186 /// // NB: Nothing happens yet other than the file has been read. We are just 187 /// // connecting all these things together and they will be invoked when we 188 /// // call the parser rule. ANTLR3_SIZE_HINT can be left at the default usually 189 /// // unless you have a very large token stream/input. Each generated lexer 190 /// // provides a token source interface, which is the second argument to the 191 /// // token stream creator. 192 /// // Note tha even if you implement your own token structure, it will always 193 /// // contain a standard common token within it and this is the pointer that 194 /// // you pass around to everything else. A common token as a pointer within 195 /// // it that should point to your own outer token structure. 196 /// // 197 /// tstream = antlr3CommonTokenStreamSourceNew(ANTLR3_SIZE_HINT, lxr->pLexer->tokSource); 198 /// 199 /// if (tstream == NULL) 200 /// { 201 /// ANTLR3_FPRINTF(stderr, "Out of memory trying to allocate token stream\n"); 202 /// exit(ANTLR3_ERR_NOMEM); 203 /// } 204 /// 205 /// // Finally, now that we have our lexer constructed, we can create the parser 206 /// // 207 /// psr = LangParserNew(tstream); // CParserNew is generated by ANTLR3 208 /// 209 /// if (psr == NULL) 210 /// { 211 /// ANTLR3_FPRINTF(stderr, "Out of memory trying to allocate parser\n"); 212 /// exit(ANTLR3_ERR_NOMEM); 213 /// } 214 /// 215 /// // We are all ready to go. Though that looked complicated at first glance, 216 /// // I am sure, you will see that in fact most of the code above is dealing 217 /// // with errors and there isn;t really that much to do (isn;t this always the 218 /// // case in C? ;-). 219 /// // 220 /// // So, we now invoke the parser. All elements of ANTLR3 generated C components 221 /// // as well as the ANTLR C runtime library itself are pseudo objects. This means 222 /// // that they are represented as pointers to structures, which contain any 223 /// // instance data they need, and a set of pointers to other interfaces or 224 /// // 'methods'. Note that in general, these few pointers we have created here are 225 /// // the only things you will ever explicitly free() as everything else is created 226 /// // via factories, that allocate memory efficiently and free() everything they use 227 /// // automatically when you close the parser/lexer/etc. 228 /// // 229 /// // Note that this means only that the methods are always called via the object 230 /// // pointer and the first argument to any method, is a pointer to the structure itself. 231 /// // It also has the side advantage, if you are using an IDE such as VS2005 that can do it 232 /// // that when you type ->, you will see a list of all the methods the object supports. 233 /// // 234 /// langAST = psr->decl(psr); 235 /// 236 /// // If the parser ran correctly, we will have a tree to parse. In general I recommend 237 /// // keeping your own flags as part of the error trapping, but here is how you can 238 /// // work out if there were errors if you are using the generic error messages 239 /// // 240 /// if (psr->pParser->rec->errorCount > 0) 241 /// { 242 /// ANTLR3_FPRINTF(stderr, "The parser returned %d errors, tree walking aborted.\n", psr->pParser->rec->errorCount); 243 /// 244 /// } 245 /// else 246 /// { 247 /// nodes = antlr3CommonTreeNodeStreamNewTree(langAST.tree, ANTLR3_SIZE_HINT); // sIZE HINT WILL SOON BE DEPRECATED!! 248 /// 249 /// // Tree parsers are given a common tree node stream (or your override) 250 /// // 251 /// treePsr = LangDumpDeclNew(nodes); 252 /// 253 /// treePsr->decl(treePsr); 254 /// nodes ->free (nodes); nodes = NULL; 255 /// treePsr ->free (treePsr); treePsr = NULL; 256 /// } 257 /// 258 /// // We did not return anything from this parser rule, so we can finish. It only remains 259 /// // to close down our open objects, in the reverse order we created them 260 /// // 261 /// psr ->free (psr); psr = NULL; 262 /// tstream ->free (tstream); tstream = NULL; 263 /// lxr ->free (lxr); lxr = NULL; 264 /// input ->close (input); input = NULL; 265 /// 266 /// return 0; 267 /// } 268 /// \endcode 269 /// 270
