Win flex-bison 的简单使用

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我是靠谱客的博主老迟到超短裙，这篇文章主要介绍Win flex-bison 的简单使用，现在分享给大家，希望可以做个参考。

Win flex-bison 的简单使用

学习编译原理的朋友，都会看到书中提到的 lex & yacc 或 flex & bison 工具组合。这两组工具在 Unix, Linux, BSD 上使用不会有太大的问题，但在 Windows 上使用通常需要安装 MinGW+ (Msys GnuWin 或Msys2 ) 或者Cygwin。Win flex-bison 提供了 flex bison for Windows 的另外一种移植，将GNU m4宏处理器源代码集成进 win flex-bison ，不依赖Msys，Msys2，Cygwin 提供的模拟类 Unix 运行环境，不依赖GNU m4宏处理器便可生成 C 目标文件。

flex 见 http://sourceforge.net/projects/flex/

bison 见 http://www.gnu.org/software/bison/

目前，Msys GnuWin 上的 flex 2.5.35 和 bison (GNU Bison) 2.4.2 版本太陈旧了, N年没更新了。

Msys2 ( http://sourceforge.net/projects/msys2/ ) 上的版本新， flex2.5.38 和 bison 3.0.2

Win flex-bison 见 http://sourceforge.net/projects/winflexbison/

Win flex-bison is a port Flex & Bison tools to the Windows platform

下面以 Win flex-bison 2.5.1和《flex & bison》第一章的简单计算器fb1-5为例，简单介绍如何使用。

首先从 http://sourceforge.net/projects/winflexbison/ 下载已经编译好的压缩文件 win_flex_bison-2.5.1.zip（不到700kb），

Update: 2014-01-04

Description

Win flex-bison is a windows port the Flex(the fast lexical analyser) and Bison (GNU parser generator). win_flex based onFlex version 2.5.37 source code and win_bisonbased on Bison version 2.7 and they depend on system libraries only.

UPDATE1: Bison version 3.0 available in Files section in win_flex_bison-2.5.zippackage.

UPDATE2: Now "winflexbison" available as package in Chocolatey (http://chocolatey.org/packages/winflexbison)

Win flex-bison WebSite

License

GNUGeneral Public License version 3.0 (GPLv3)

解压到某一文件夹（如 winFlexBison），将这个文件夹增加到 path 环境变量中，就可以命令行使用了。

Bison规则描述文件 fb1-5.y

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/* Companionsource code for "flex & bison", published by O'Reilly
 * Media, ISBN 978-0-596-15597-1
 * Copyright (c) 2009, Taughannock Networks.All rights reserved.
 * See the README file for license conditionsand contact info.
 * $Header: /home/johnl/flnb/code/RCS/fb1-5.y,v2.1 2009/11/08 02:53:18 johnl Exp $
 */

/* simplestversion of calculator */

#  include <stdio.h>

/* declare tokens*/
%token NUMBER
%token ADD SUB MULDIV ABS
%token OP CP
%token EOL

calclist: /*nothing */
 | calclist exp EOL { printf("= %dn>", $2); }
 | calclist EOL { printf("> "); }/* blank line or a comment */
 ;

exp: factor
 | exp ADD exp { $$ = $1 + $3; }
 | exp SUB factor { $$ = $1 - $3; }
 | exp ABS factor { $$ = $1 | $3; }
 ;

factor: term
 | factor MUL term { $$ = $1 * $3; }
 | factor DIV term { $$ = $1 / $3; }
 ;

term: NUMBER
 | ABS term { $$ = $2 >= 0? $2 : - $2; }
 | OP exp CP { $$ = $2; }
 ;

main()
{
  printf("> ");
  yyparse();
}

yyerror(char *s)
{
  fprintf(stderr, "error: %sn", s);
}

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/* Companionsource code for "flex & bison", published by O'Reilly
 * Media, ISBN 978-0-596-15597-1
 * Copyright (c) 2009, Taughannock Networks.All rights reserved.
 * See the README file for license conditionsand contact info.
 * $Header: /home/johnl/flnb/code/RCS/fb1-5.y,v2.1 2009/11/08 02:53:18 johnl Exp $
 */

/* simplestversion of calculator */

%{

#  include <stdio.h>

%}

/* declare tokens*/
%token NUMBER
%token ADD SUB MULDIV ABS
%token OP CP
%token EOL

%%

calclist: /*nothing */
 | calclist exp EOL { printf("= %dn>", $2); }
 | calclist EOL { printf("> "); }/* blank line or a comment */
 ;

exp: factor
 | exp ADD exp { $$ = $1 + $3; }
 | exp SUB factor { $$ = $1 - $3; }
 | exp ABS factor { $$ = $1 | $3; }
 ;

factor: term
 | factor MUL term { $$ = $1 * $3; }
 | factor DIV term { $$ = $1 / $3; }
 ;

term: NUMBER
 | ABS term { $$ = $2 >= 0? $2 : - $2; }
 | OP exp CP { $$ = $2; }
 ;

%%

main()
{
  printf("> ");
  yyparse();
}

yyerror(char *s)
{
  fprintf(stderr, "error: %sn", s);
}

Flex词法分析文件 fb1-5.l

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/* Companionsource code for "flex & bison", published by O'Reilly
 * Media, ISBN 978-0-596-15597-1
 * Copyright (c) 2009, Taughannock Networks.All rights reserved.
 * See the README file for license conditionsand contact info.
 * $Header: /home/johnl/flnb/code/RCS/fb1-5.l,v2.1 2009/11/08 02:53:18 johnl Exp $
 */

/* recognizetokens for the calculator and print them out */

%{

# include"fb1-5.tab.h"

%}

%%

"+"  { return ADD; }
"-"   { return SUB; }
"*"  { return MUL; }
"/"   { return DIV; }
"|"     { return ABS; }
"("     { return OP; }
")"     { return CP; }

[0-9]+    { yylval = atoi(yytext); return NUMBER; }

n      { return EOL; }
"//".* 
[ t]   { /* ignore white space */ }
.      { yyerror("Mystery character%cn", *yytext); }

%%

手工运行以下命令

win_bison -d fb1-5.y

生成 fb1-5.tab.h 和fb1-5.tab.c 文件

win_flex --nounistdfb1-5.l 或win_flex --wincompat fb1-5.l

生成 lex.yy.c 文件。--nounistd 和 --wincompat 选项使生成的 lex.yy.c 不依赖<unistd.h> 可以用 VC 编译，否则就只能用 gcc 编译了。

--wincompat 为 win_flex 所增加的设置选项，在 flex --nounistd (do not include <unistd.h> ) 的基础上，减少 VC 的 compile warning (uses <io.h> instead of <unistd.h> and _isatty, _fileno functions )，另外在生成的lex.yy.c 文件中添加：

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/*windows compatibility case*/
#include <io.h>
#define isatty _isatty
#define fileno _fileno

其实，也可这样解决：

warning C4013: “isatty” undefined; assuming extern returning int

在 .l 文件中包含 # include <io.h>

warning C4013: “strdup” undefined; assuming extern returning int

在 .l 或 .y 文件中包含 # include <string.h>

warning C4996: 'isatty': The POSIX name for this item is deprecated. Instead, use the ISO C++ conformant name: _isatty. See online help for details.

warning C4996: 'fileno': The POSIX name for this item is deprecated. Instead, use the ISO C++ conformant name: _fileno. See online help for details.

warning C4996: 'strdup': The POSIX name for this item is deprecated. Instead, use the ISO C++ conformant name: _strdup. See online help for details.

在 VC 添加 _CRT_NONSTDC_NO_DEPRECATE 编译宏定义，见 http://msdn.microsoft.com/en-us/library/ms235384.aspx 说明。

为了项目管理方便可将 lex.yy.c 重命名为 fb1-5.c ，用 cl 手工编译

cl fb1-5.cfb1-5.tab.c libfl.a 或 cl fb1-5.c fb1-5.tab.c libfl.lib

生成 fb1-5.exe ，由于用到 yywrap() 需要链接 flex 的 libfl.a 库。用VC编译的话，可以将 libfl.a 重名为libfl.lib 更直观。

运行一下fb1-5.exe

你也可以建立一个MakeFile文件 makefile.mak

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# Build a Simple Calc with fb1-5.y and fb1-5.l

!IF "$(OS)" == "Windows_NT"
NULL=
!ELSE 
NULL=nul
!ENDIF 

CC=cl
CFLAGS=/nologo /DNDEBUG /D_CRT_SECURE_NO_WARNINGS /D_CRT_NONSTDC_NO_DEPRECATE /O2 /W3
LD=link
LDFLAGS=/nologo
LIBS=libfl.lib
MOVE=move /Y

ALL : fb1-5.exe

CLEAN :
	-@erase "*.obj"
	-@erase "fb1-5.c"
	-@erase "fb1-5.tab.c"
	-@erase "fb1-5.tab.h"
	-@erase "fb1-5.exe"

OBJS=
	fb1-5.obj 
	fb1-5.tab.obj 

"fb1-5.tab.c" : fb1-5.y
    if not exist "$@/$(NULL)" win_bison -d $**

"fb1-5.tab.h" : fb1-5.y
    if not exist "$@/$(NULL)" win_bison -d $**

"fb1-5.c" : fb1-5.l
	if not exist "$@/$(NULL)" win_flex --nounistd $** && $(MOVE) lex.yy.c $@

"fb1-5.exe" : $(OBJS)
	$(LD) $(LDFLAGS) /out:$@ $** $(LIBS)

"fb1-5.obj" : fb1-5.c fb1-5.tab.h
	$(CC) $(CFLAGS) /c fb1-5.c

"fb1-5.tab.obj" : fb1-5.tab.c fb1-5.tab.h
	$(CC) $(CFLAGS) /c fb1-5.tab.c

用 nmake /f makefile.mak来构建。

另外一个国外图文并茂的教程为 Using flex and bison in MSVC++

http://www.di-mgt.com.au/flex_and_bison_in_msvc.html

本文就是从那演化来的。

libfl.a （ v2.5.37 ）；从 GnuWin ，Msys , Msys2 中提取

Msys2 http://sourceforge.net/projects/msys2/

也可以从 http://pan.baidu.com/s/1eQcKMgM 下载。

不链接 libfl.a 例程可以采用以下方式:

你可以在 fb1-5.l 文件中增加 %option noyywrap 选项

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%{
# include "fb1-5.tab.h"
%}

%option noyywrap

%%

或提供 yywrap() 实例

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int yywrap()
{
	return 1;
}

或在 flex 执行选项增加 --noyywrap 选项。

都可以不用链接 flex 提供的 libfl.a 或 libfl.lib 例程( It contains versions of main() and yywrap(). )。

细心的话，你会发现 fb1-5.l 中的 yyerror() 调用2个参数，不同于 fb1-5.y 中的 yyerror(char *s)，但的确调用的是yyerror(char *s)，并编译通过，并生成执行文件。

运行中输入出错时，出错信息只是输出：

> error: Mystery character %c

与原设想的有出入，没有多大实用性。

这时，你可在 fb1-5.l 文件中增加 %option yylineno 选项，重新处理输出出错信息。

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.	{ printf("error: Mystery character %c(line:%d)n", *yytext, yylineno); }

接下来，在 fb1-5.y 中增加正负号处理，即增加一元操作符 +,-

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term: NUMBER
 | SUB term { $$ = - $2; /* unary minus */ }
 | ADD term { $$ = $2; /* unary plus */ }
 | ABS term { $$ = $2 >= 0? $2 : - $2; }
 | OP exp CP { $$ = $2; } ;

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同理，可以根据需要，添加想要的操作符和函数。

修改后完整的源文件如下：

fb1-5.l

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/* Companion source code for "flex & bison", published by O'Reilly
 * Media, ISBN 978-0-596-15597-1
 * Copyright (c) 2009, Taughannock Networks. All rights reserved.
 * See the README file for license conditions and contact info.
 * $Header: /home/johnl/flnb/code/RCS/fb1-5.l,v 2.1 2009/11/08 02:53:18 johnl Exp $
 */

/* recognize tokens for the calculator and print them out */

%{
#include <io.h>
# include "fb1-5.tab.h"
%}

%option noyywrap
%option yylineno

%%
"+"	{ return ADD; }
"-"	{ return SUB; }
"*"	{ return MUL; }
"/"	{ return DIV; }
"|"     { return ABS; }
"("     { return OP; }
")"     { return CP; }
[0-9]+	{ yylval = atoi(yytext); return NUMBER; }

n      { return EOL; }
"//".*  
[ t]   { /* ignore white space */ }
.	{ printf("error: Mystery character %c(line:%d)n", *yytext, yylineno); }
%%

fb1-5.y

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/* Companion source code for "flex & bison", published by O'Reilly
 * Media, ISBN 978-0-596-15597-1
 * Copyright (c) 2009, Taughannock Networks. All rights reserved.
 * See the README file for license conditions and contact info.
 * $Header: /home/johnl/flnb/code/RCS/fb1-5.y,v 2.1 2009/11/08 02:53:18 johnl Exp $
 */

/* simplest version of calculator */

%{
#include <stdio.h>

void yyerror(char *s);
%}

/* declare tokens */
%token NUMBER
%token ADD SUB MUL DIV ABS
%token OP CP
%token EOL

calclist: /* nothing */
 | calclist exp EOL { printf("= %dn> ", $2); }
 | calclist EOL { printf("> "); } /* blank line or a comment */
 ;

exp: factor
 | exp ADD exp { $$ = $1 + $3; }
 | exp SUB factor { $$ = $1 - $3; }
 | exp ABS factor { $$ = $1 | $3; }
 ;

factor: term
 | factor MUL term { $$ = $1 * $3; }
 | factor DIV term { $$ = $1 / $3; }
 ;

term: NUMBER
 | SUB term { $$ = - $2; /* unary minus */ }
 | ADD term { $$ = $2; /* unary plus */ }
 | ABS term { $$ = $2 >= 0? $2 : - $2; }
 | OP exp CP { $$ = $2; }
 ;
%%
int main( void )
{
  printf("> "); 
  yyparse();
  return 0;
}

void yyerror(char *s)
{
  fprintf(stderr, "error: %sn", s);
}

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/* Companion source code for "flex & bison", published by O'Reilly
 * Media, ISBN 978-0-596-15597-1
 * Copyright (c) 2009, Taughannock Networks. All rights reserved.
 * See the README file for license conditions and contact info.
 * $Header: /home/johnl/flnb/code/RCS/fb1-5.y,v 2.1 2009/11/08 02:53:18 johnl Exp $
 */

/* simplest version of calculator */

%{
#include <stdio.h>

void yyerror(char *s);
%}

/* declare tokens */
%token NUMBER
%token ADD SUB MUL DIV ABS
%token OP CP
%token EOL

%%

calclist: /* nothing */
 | calclist exp EOL { printf("= %dn> ", $2); }
 | calclist EOL { printf("> "); } /* blank line or a comment */
 ;

exp: factor
 | exp ADD exp { $$ = $1 + $3; }
 | exp SUB factor { $$ = $1 - $3; }
 | exp ABS factor { $$ = $1 | $3; }
 ;

factor: term
 | factor MUL term { $$ = $1 * $3; }
 | factor DIV term { $$ = $1 / $3; }
 ;

term: NUMBER
 | SUB term { $$ = - $2; /* unary minus */ }
 | ADD term { $$ = $2; /* unary plus */ }
 | ABS term { $$ = $2 >= 0? $2 : - $2; }
 | OP exp CP { $$ = $2; }
 ;
%%
int main( void )
{
  printf("> "); 
  yyparse();
  return 0;
}

void yyerror(char *s)
{
  fprintf(stderr, "error: %sn", s);
}

makefile.mak （适用于 Msys2中的 flex& bison 在 Windows + VC, 修改相应 LEX , YACC 变量,可用于 win flex-bison )

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# Build a Simple Calc with fb1-5.y and fb1-5.l

!IF "$(OS)" == "Windows_NT"
NULL=
!ELSE
NULL=nul
!ENDIF

CC=cl
CFLAGS=/nologo /DNDEBUG /D_CRT_SECURE_NO_WARNINGS /O2 /W3
LD=cl
LDFLAGS=/nologo /link
MOVE=move /Y
LEX=flex
YACC=bison

ALL : fb1-5.exe

CLEAN :
	-@erase "*.obj"
	-@erase "fb1-5.c"
	-@erase "fb1-5.tab.c"
	-@erase "fb1-5.tab.h"
	-@erase "fb1-5.exe"

OBJS=
	fb1-5.obj 
	fb1-5.tab.obj 

"fb1-5.tab.c" : fb1-5.y
    if not exist "$@/$(NULL)" $(YACC) -d $**

"fb1-5.tab.h" : fb1-5.y
    if not exist "$@/$(NULL)" $(YACC) -d $**

"fb1-5.c" : fb1-5.l
	if not exist "$@/$(NULL)" $(LEX) --nounistd $** && $(MOVE) lex.yy.c $@

"fb1-5.exe" : $(OBJS)
	$(LD) $** $(LDFLAGS) /out:$@

"fb1-5.obj" : fb1-5.c fb1-5.tab.h
	$(CC) $(CFLAGS) /c fb1-5.c

"fb1-5.tab.obj" : fb1-5.tab.c fb1-5.tab.h
	$(CC) $(CFLAGS) /c fb1-5.tab.c