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