CMake&yacc&lex

2019-11-11 02:22:15

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Reference

cmake bison command: https://cmake.org/cmake/help/v3.6/module/FindBISON.htmlcmake flex command: https://cmake.org/cmake/help/v3.6/module/FindFLEX.html

内容

CMake处理lex和yacc文件。即自动将lex&yacc文件转换成为c/c++文件，然后生成库文件或可执行文件。

lex

这里只有一个lex文件（test.ll），然后生成可执行文件ttest。——test是cmake保留字，所以这里用ttest。

目录结构

两个子目录：

test/src: test.ll, CMakeLists.txttest/bin: 工作目录，一开始为空，生成的文件都放在这里。

文件

test.ll

%{#include <string>#include <iostream>%}%%[/t ]+ /* white space */[a-zA-Z]+ { std::string Word(yytext); std::cout<<"word: "<<word<<std::endl; }[0-9]+ { std::string number(yytext); std::cout<<"number: "<<number<<std::endl; }.|/n {ECHO; /* normal default anyway */ }%%int main(){ std::cout<<"Lex and C++"<<std::endl; yylex(); return 0;}

CMakeLists.txt

cmake_minimum_required(VERSION 2.8)PRoject(ttest)# bison and flexfind_package(BISON)find_package(FLEX)FLEX_TARGET(ttest_lexer test.ll ${PROJECT_BINARY_DIR}/test.cpp)# mainset (MAIN_SRC ${PROJECT_BINARY_DIR}/test.cpp)add_executable(ttest ${MAIN_SRC})# librariesfind_library(LEX_LIB l)target_link_libraries(ttest ${LEX_LIB})

或者

cmake_minimum_required(VERSION 2.8)project(ttest)# bisonfind_package(FLEX)FLEX_TARGET(ttest_lexer test.ll ${CMAKE_CURRENT_BINARY_DIR}/test.cpp)# mainadd_executable(ttest ${CMAKE_CURRENT_BINARY_DIR}/test.cpp)# librariesfind_library(LEX_LIB l)target_link_libraries(ttest ${LEX_LIB})

Run

$ ./ttest Lex and C++abd 123word: abdnumber: 123^C

lexer&parser

Files

两个文件：test.ll, test.yy. 最后生成可执行文件ttest。

test.ll

%{//#include <string>#include "y.tab.h"%}%%[/t ]+ ;[a-zA-Z]+ {return OBJECT;}[0-9]+ {return PRICE;}.|/n {ECHO;}

test.yy

%{#include <stdio.h> extern int yylex (void);void yyerror(const char *s, ...);%}%token OBJECT PRICE%%description: object PRICE { printf("pass.../n"); } ;object: OBJECT ;%%extern FILE *yyin;int main(int argc, const char* argv[]){ if (argc != 2) { printf("Usage: %s filename/n", argv[0]); return 0; } yyin = fopen(argv[1], "rb"); if (NULL == yyin) { printf("Open file failed: %s/n", argv[1]); return 0; } while(!feof(yyin)) { yyparse(); } fclose(yyin); yyin = NULL; return 0;}void yyerror(const char *s, ...){ fprintf(stderr, "%s/n", s);}

不用cmake

执行如下命令：

yacc -d test.yylex test.llgcc -o test lex.yy.c y.tab.c -ll

运行示例：

$ ./test Usage: ./test filename$ echo phone 1000 > ok.txt$ echo tom jerry > fail.txt$ ./test ok.txt pass...$ ./test fail.txt syntax error$

用cmake

首先修改test.ll中的头文件名称：

#include "y.tab.h" --> #include "parser.h"

同样创建src/bin/CMakeLists.txt。其中cmake文件内容：

cmake_minimum_required(VERSION 3.5)project(ttest)# bison and flexfind_package(BISON)find_package(FLEX)BISON_TARGET(ttest_parser test.yy ${CMAKE_CURRENT_BINARY_DIR}/parser.cpp DEFINES_FILE ${CMAKE_CURRENT_BINARY_DIR}/parser.h )FLEX_TARGET(ttest_lexer test.ll ${CMAKE_CURRENT_BINARY_DIR}/lexer.cpp)# default header file is parser.hppADD_FLEX_BISON_DEPENDENCY(ttest_lexer ttest_parser)# maininclude_directories(${CMAKE_CURRENT_BINARY_DIR})set (MAIN_SRC ${CMAKE_CURRENT_BINARY_DIR}/lexer.cpp ${CMAKE_CURRENT_BINARY_DIR}/parser.cpp# or ${BISON_ttest_parser_OUTPUTS}${FLEX_ttest_lexer_OUTPUTS} )add_executable(ttest ${MAIN_SRC})find_library(LEX_LIB l)target_link_libraries(ttest ${LEX_LIB})

注意到对于生成的cpp文件的两种引用方式。

另，根据https://cmake.org/cmake/help/v3.6/release/3.4.html的说法，可能cmake版本要求至少是3.4:

The FindBISON module BISON_TARGET macro learned a new DEFINES_FILE option to specify a custom output header to be generated.

lex&parser打包成库文件

假定要把lexer&parser的代码打包成lib，然后供其他的cpp调用。为此，把test.yy中的main()搬到一个新的main.cpp文件中：

#include <stdio.h>extern FILE *yyin;extern int yyparse();int main(int argc, const char* argv[]){ if (argc != 2) { printf("Usage: %s filename/n", argv[0]); return 0; } yyin = fopen(argv[1], "rb"); if (NULL == yyin) { printf("Open file failed: %s/n", argv[1]); return 0; } while(!feof(yyin)) { yyparse(); } fclose(yyin); yyin = NULL; return 0;}

然后cmake文件改为：

cmake_minimum_required(VERSION 3.5)project(ttest)# bison and flexfind_package(BISON)find_package(FLEX)BISON_TARGET(ttest_parser test.yy ${CMAKE_CURRENT_BINARY_DIR}/parser.cpp DEFINES_FILE ${CMAKE_CURRENT_BINARY_DIR}/parser.h )FLEX_TARGET(ttest_lexer test.ll ${CMAKE_CURRENT_BINARY_DIR}/lexer.cpp)# default header file is parser.hppADD_FLEX_BISON_DEPENDENCY(ttest_lexer ttest_parser)include_directories(${CMAKE_CURRENT_BINARY_DIR})add_library(myparser ${BISON_ttest_parser_OUTPUTS} ${FLEX_ttest_lexer_OUTPUTS} )# mainadd_executable(ttest main.cpp)target_link_libraries(ttest myparser)find_library(LEX_LIB l)target_link_libraries(ttest ${LEX_LIB})

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