Basic System parser Flex , bison , g++ , ubuntu -linux

Readme.md

all these files are developed on linux and are ready to be extensible.

the folder structure suggested {project root}

/Readme.md

{bin}-for storing the compiled output {test}-for storing the scripts upon which the compiled system is to be tested

./(^)/enter.code

{compiler}-contains all the source files

./(^).lex.l

..grammer.y

..main.cc

..Makefile

Packages required to build this module >> flex , bison

[[ use sudo , or yum to install it onto your system ]]

enter.code

enter: -> {
	
}

grammer.y

%{
    #include <stdio.h>
    void yyerror(char *);
    int yylex(void);

    int sym[26];
%}

%token NAME COLON RIGHT_ARROW LEFT_BRACE RIGHT_BRACE 

%define api.value.type {double}

%start input 
%%

input:
    NAME COLON RIGHT_ARROW LEFT_BRACE RIGHT_BRACE
    |%empty

%%

void yyerror(char *s) {
    fprintf(stderr, "%s\n", s);
}

lex.l

%option noyywrap
%{
    #include "grammer.tab.h"
%}
alpha       [a-zA-Z]
name        {alpha}([0-9]*{alpha}*)+
whitespace  [ \r\f\v\t]
linefeed    \n
%%
{name}          {printf("LEX:: name \n");return NAME;}
":"             {printf("LEX:: COLON \n");return COLON;}
"->"            {printf("LEX:: RIGHT_ARROW \n");return RIGHT_ARROW;}
"{"             {printf("LEX:: LEFT_BRACE \n");return LEFT_BRACE;}
"}"             {printf("LEX:: RIGHT_BRACE \n");return RIGHT_BRACE;}

{whitespace}
{linefeed}      ++yylineno;

%%

main.cc

#include <iostream>
extern "C"
{
	void yyerror(const char *);
	int yyparse();
	int yylex();
}
int main()
{
	int result =yyparse();
	if (result)
	{
		std::cout<< "the input is valid"<<std::endl;
	}else{
		std::cout<< "the input is valid"<<std::endl;
	}
	return result;
}

Makefile

all:
	$(MAKE) grammer
	$(MAKE)	lex
	gcc -c compiler/grammer.tab.c compiler/lex.yy.c
	mv *.o compiler
	ar rvs compiler/lexgram.a compiler/grammer.tab.o compiler/lex.yy.o
	g++ -o bin/freamps  -Wall -Wextra compiler/main.cc compiler/lexgram.a
grammer:
	bison -d compiler/grammer.y
	mv grammer.tab.* compiler
lex:
	flex compiler/lex.l
	mv lex.yy.c compiler