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)
Categories
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
/* 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("= %d\n>", $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: %s\n", s); }
Flex词法分析文件 fb1-5.l
/* 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%c\n", *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:
/*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
# 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:
%{ # include "fb1-5.tab.h" %} %option noyywrap %%
或 提供 yywrap() 实例
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。
. { 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 +,-
term: NUMBER | SUB term { $$ = - $2; /* unary minus */ } | ADD term { $$ = $2; /* unary plus */ } | ABS term { $$ = $2 >= 0? $2 : - $2; } | OP exp CP { $$ = $2; } ;同理,可以根据需要,添加想要的操作符和函数。
修改后完整的源文件如下:
fb1-5.l
/* Companion source code for "flex & bison", published by O'Reilly * Media, ISBN 978-0-596-15597-1 * Copyright (c) 2009, Taughannock Networks. All rights reserved. * See the README file for license conditions and contact info. * $Header: /home/johnl/flnb/code/RCS/fb1-5.l,v 2.1 2009/11/08 02:53:18 johnl Exp $ */ /* recognize tokens for the calculator and print them out */ %{ #include <io.h> # include "fb1-5.tab.h" %} %option noyywrap %option yylineno %% "+" { return ADD; } "-" { return SUB; } "*" { return MUL; } "/" { return DIV; } "|" { return ABS; } "(" { return OP; } ")" { return CP; } [0-9]+ { yylval = atoi(yytext); return NUMBER; } \n { return EOL; } "//".* [ \t] { /* ignore white space */ } . { printf("error: Mystery character %c(line:%d)\n", *yytext, yylineno); } %%
fb1-5.y
/* Companion source code for "flex & bison", published by O'Reilly * Media, ISBN 978-0-596-15597-1 * Copyright (c) 2009, Taughannock Networks. All rights reserved. * See the README file for license conditions and contact info. * $Header: /home/johnl/flnb/code/RCS/fb1-5.y,v 2.1 2009/11/08 02:53:18 johnl Exp $ */ /* simplest version of calculator */ %{ #include <stdio.h> void yyerror(char *s); %} /* declare tokens */ %token NUMBER %token ADD SUB MUL DIV ABS %token OP CP %token EOL %% calclist: /* nothing */ | calclist exp EOL { printf("= %d\n> ", $2); } | calclist EOL { printf("> "); } /* blank line or a comment */ ; exp: factor | exp ADD exp { $$ = $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 { $$ = $2 >= 0? $2 : - $2; } | OP exp CP { $$ = $2; } ; %% int main( void ) { printf("> "); yyparse(); return 0; } void yyerror(char *s) { fprintf(stderr, "error: %s\n", s); }makefile.mak (适用于 Msys2中的 flex& bison 在 Windows + VC, 修改相应 LEX , YACC 变量,可用于 win flex-bison )
# Build a Simple Calc with fb1-5.y and fb1-5.l !IF "$(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在 MSYS2 shell 中运行结果
Win flex_bison 2.5.1 在 2014.3.27 增加了 custom_build_rules 文件夹
其中 how_to_use.txt 中为 https://sourceforge.net/p/winflexbison/wiki/Visual%20Studio%20custom%20build%20rules/
"Visual Studio custom build rules" Wiki Pages
These steps help you setup custom build rules for Visual Studio 2010 and up.
内容与 http://www.di-mgt.com.au/flex_and_bison_in_msvc.html 差不多,但是没有 如何增加命令参数 的步骤,令人不解!
转载本文请注明来自 http://blog.csdn.net/gocad/article/details/21866627