Flex,Bison和C:寻找一个非常基本的介绍

我正在寻找一个非常简短的flex和bison工作示例,附带Makefile,它使用了内置规则.我已经尝试过几个谷歌的结果,这些结果很乱,不会构建,或者是C++,这是不可接受的.赞赏良好的在线资源和简短的示例代码.

额外

     # Makefile example -- scanner and parser.
     # Creates "myprogram" from "scan.l", "parse.y", and "myprogram.c"
     #
     LEX     = flex
     YACC    = bison -y
     YFLAGS  = -d
     objects = scan.o parse.o myprogram.o

     myprogram: $(objects)
     scan.o: scan.l parse.c
     parse.o: parse.y
     myprogram.o: myprogram.c

我想要一个看起来与此类似的Makefile,附带的源文件可以做任意简单的事情.

flex项目本身带有一组不错的示例,包括make文件和bison文件.

https://github.com/westes/flex/releases

有关该主题的优秀介绍,我建议lex和yacc第2版:

http://oreilly.com/catalog/9781565920002

最后,到这里快速入门:

http://ds9a.nl/lex-yacc/cvs/lex-yacc-howto.html

编辑:

正如巴特所说,另一个来源是:http://oreilly.com/catalog/9780596155988/

以下是我用来启动flex项目的框架文件.它使用gnu getopts来解析命令行选项并获取文件名.我没有声称可移植性或易用性!:)

/*
 * This file is part of flex.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 
 * Neither the name of the University nor the names of its contributors
 * may be used to endorse or promote products derived from this software
 * without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE.
 */

    /************************************************** 
        start of definitions section

    ***************************************************/

%{
/* A template scanner file to build "scanner.c". */
#include 
#include 
#include 
#include 
/*#include "parser.h" */

//put your variables here
char FileName[256];
FILE *outfile;
char **myOut;
char inputName[256];




// flags for command line options
static int specificFile_flag = 0;
static int output_flag = 0;
static int help_flag = 0;

%}


%option 8bit outfile="scanner.c"
%option nounput nomain noyywrap 
%option warn

%x header
%x fileType
%x final

%%
    /************************************************ 
        start of rules section

    *************************************************/


    /* these flex patterns will eat all input */ 
. { }
\n { }


%%
    /**************************************************** 
        start of code section


    *****************************************************/

int main(int argc, char **argv);

int main (argc,argv)
int argc;
char **argv;
{
    /****************************************************
        The main method drives the program. It gets the filename from the
        command line, and opens the initial files to write to. Then it calls the lexer.
        After the lexer returns, the main method finishes out the report file,
        closes all of the open files, and prints out to the command line to let the
        user know it is finished.
    ****************************************************/

    int c;

    // the gnu getopt library is used to parse the command line for flags
    // afterwards, the final option is assumed to be the input file

    while (1) {
        static struct option long_options[] = {
            /* These options set a flag. */
            {"specific-file", no_argument,       &specificFile_flag, 1},
            {"help",   no_argument,     &help_flag, 1},
            /* These options don't set a flag. We distinguish them by their indices. */

            {"debug", no_argument,       0, 'd'},
            {"specificFile", no_argument,       0, 's'},
            {"useStdOut", no_argument,       0, 'o'},
            {0, 0, 0, 0}
        };
           /* getopt_long stores the option index here. */
        int option_index = 0;
        c = getopt_long (argc, argv, "dso",
            long_options, &option_index);

        /* Detect the end of the options. */
        if (c == -1)
            break;

        switch (c) {
            case 0:
               /* If this option set a flag, do nothing else now. */
               if (long_options[option_index].flag != 0)
                 break;
               printf ("option %s", long_options[option_index].name);
               if (optarg)
                 printf (" with arg %s", optarg);
               printf ("\n");
               break;

            case 'd':
                break;

            case 's':
               specificFile_flag = 1;
               break;

            case 'o':
               output_flag = 1;
               break;


            case '?':
               /* getopt_long already printed an error message. */
               break;

            default:
               abort ();
            }
    }

    if (help_flag == 1) {
        printf("proper syntax is: addressGrabber.exe [OPTIONS]... INFILE OUTFILE\n");
        printf("grabs address from prn files\n\n");
        printf("Option list: \n");
        printf("-s    --specific-file   changes INFILE from a prn list to a specific prn\n");
        printf("-d              turns on debug information\n");
        printf("-o                      sets output to stdout\n");
        printf("--help                  print help to screen\n");
        printf("\n");
        printf("list example: addressGrabber.exe list.csv\n");
        printf("prn example: addressGrabber.exe -s 01110500.prn\n\n");
        printf("If infile is left out, then stdin is used for input.\n");
        printf("If outfile is a filename, then that file is used.\n");
        printf("If there is no outfile, then infile-EDIT.tab is used.\n");
        printf("There cannot be an outfile without an infile.\n");
        return 0;
    }

    //get the filename off the command line and redirect it to input
    //if there is no filename or it is a - then use stdin


    if (optind < argc) {
        FILE *file;

        file = fopen(argv[optind], "rb");
        if (!file) {
            fprintf(stderr, "Flex could not open %s\n",argv[optind]);
            exit(1);
        }
        yyin = file;
        strcpy(inputName, argv[optind]);
    }
    else {
        printf("no input file set, using stdin. Press ctrl-c to quit");
        yyin = stdin;
        strcpy(inputName, "\b\b\b\b\bagainst stdin");
    }

    //increment current place in argument list
    optind++;


    /********************************************
        if no input name, then output set to stdout
        if no output name then copy input name and add -EDIT.csv
        if input name is '-' then output set to stdout
        otherwise use output name

    *********************************************/
    if (optind > argc) {
        yyout = stdout;
    }   
    else if (output_flag == 1) {
        yyout = stdout;
    }
    else if (optind < argc){
        outfile = fopen(argv[optind], "wb");
        if (!outfile) {
                fprintf(stderr, "Flex could not open %s\n",FileName);
                exit(1);
            }
        yyout = outfile;
    }
    else {
        strncpy(FileName, argv[optind-1], strlen(argv[optind-1])-4);
        FileName[strlen(argv[optind-1])-4] = '\0';
        strcat(FileName, "-EDIT.tab");
        outfile = fopen(FileName, "wb");
        if (!outfile) {
                fprintf(stderr, "Flex could not open %s\n",FileName);
                exit(1);
            }
        yyout = outfile;
    }


    yylex();
    if (output_flag == 0) {
        fclose(yyout);
    }
    printf("Flex program finished running file %s\n", inputName);
    return 0;
}

最后,由于人们不断检查这个,我还有一个示例词法分析器和解析器与github上的makefile.