另外
我正在寻找一个非常短的flex和bison的工作示例，附带使用内置规则的Makefile。我试过几个谷歌搜索结果，它们很混乱，无法构建，或者是用c++编写的，这是不可接受的。好的在线资源和简短的示例代码是赞赏。
另外
# 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Makefile，它看起来大约像这样与附加的源文件做一些任意简单的事情。
flex项目本身提供了一组不错的示例，包括make文件和bison文件。
https://github.com/westes/flex/releases
对于这个主题的优秀介绍，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Bart提到的，另一个来源是:http://oreilly.com/catalog/9780596155988/
下面是我用来启动一个flex项目的骨架文件。它使用gnu getopts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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <getopt.h>
/*#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 OUTFILEn");
printf("grabs address from prn filesnn");
printf("Option list: n");
printf("-s --specific-file changes INFILE from a prn list to a specific prnn");
printf("-d turns on debug informationn");
printf("-o sets output to stdoutn");
printf("--help print help to screenn");
printf("n");
printf("list example: addressGrabber.exe list.csvn");
printf("prn example: addressGrabber.exe -s 01110500.prnnn");
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 %sn",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, "bbbbbagainst 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 %sn",FileName);
exit(1);
}
yyout = outfile;
}
else {
strncpy(FileName, argv[optind-1], strlen(argv[optind-1])-4);
FileName[strlen(argv[optind-1])-4] = ' ';
strcat(FileName, "-EDIT.tab");
outfile = fopen(FileName, "wb");
if (!outfile) {
fprintf(stderr, "Flex could not open %sn",FileName);
exit(1);
}
yyout = outfile;
}
yylex();
if (output_flag == 0) {
fclose(yyout);
}
printf("Flex program finished running file %sn", inputName);
return 0;
}
最后，由于人们一直在检查这个，我也有一个示例lexer和解析器与makefile在github上。
你可以从维基百科的野牛页面开始。它有一个用bison编写的可重入解析器的完整示例代码。它使用flex作为词法分析器，并提供了如何使用它的示例代码。
如果您有任何更正，我提前感谢您:)
LATER:维基百科上的代码已经在linux (gcc)和windows (visual studio)上测试过了，应该也可以在其他编译器上工作。
GNU Manual呢?
Bison文档是一个非常好的计算器示例。我用它从野牛开始。c++示例使用flex扫描器。用c写很容易。
编译器:原理、技术和工具，Alfred V. Aho, Ravi Sethi, Jeffrey D. Ullman