基本数据类型： int，double，point?, char, bool
int： +-*/^|~&
double: +-*/
point: *
bool: ==, !=, &&, ||, !
数组： [const]
语句： 条件，选择，循环,强制转移
条件： if/else
选择： switch case ：
循环： for
函数： 类型+标示符+(*)+{*}
模板： Template<*>
结构体： struct，构造函数，析构函数，::
注释： //
分隔符： ;, {}
包含： #include<>
//输入输出流: cin, cout
宏：Define
static
main()
保留字：int, double, char, Point/->/%, const, bool , !=, <,>,=, ==, &&, ||, !, ^, &, +,-,*,/,,|,^,~,[],
转移控制：if/else, switch/case/:, for, break, continue
模板：Template<T>
自定义数据类型：struct, ::,
句子隔断符：;,{}
包含：#include<>
宏：Define
代码：
lex.h:
#define INT 0
#define DOUBLE 1
#define CHAR 2
#define POINT 3
#define ARROW 4
#define ADDR 5
#define CONST 6
#define BOOL 7
#define FUNCTION 8
#define IF 9
#define ELSE 10
#define SWITCH 11
#define CASE 12
#define COLON 13
#define FOR 14
#define BREAK 15
#define CONTINUE 16
#define TEMPLATE 17
#define STRUCT 18
#define STATIC 19
#define DOUBLECOLON 20
#define INCLUDE 21
#define DEFINE 22
#define IDENTIFIER 23
#define LDOUBLE 24
#define LINTEGER 25
#define BOOLAND 26
#define BOOLOR 27
#define BOOLNOT 28
#define ASSIGN 29
#define EQ 30
#define NE 31
#define LT 32
#define LE 33
#define GT 34
#define GE 35
#define LPAREN 36
#define RPAREN 37
#define LBRACE 38
#define RBRACE 39
#define DOT 40
#define COMMA 41
#define PLUS 42
#define MINUS 43
#define MUL 44
#define DIV 45
#define BITOR 46
#define BITXOR 47
#define BITNOT 48
#define BITAND 49
#define SQUOTE 50
#define DQUOTE 51
#define SEMICOLON 52
#define RETURN 53
#define ANNOTATION 54
lex.l:
%{
#include "lex.h"
#include <stdlib.h>
extern int yylval;
%}
%%
int {printf("It is a keyword %s\n",yytext); return INT;}
double {printf("It is a keyword %s\n",yytext); return DOUBLE;}
char {printf("It is a keyword %s\n",yytext); return CHAR;}
Point {printf("It is a keyword %s\n",yytext); return (POINT); }
const {printf("It is a keyword %s\n",yytext); return CONST;}
bool {printf("It is a keyword %s\n",yytext); return BOOL;}
function {printf("It is a keyword %s\n",yytext); return FUNCTION;}
if {printf("It is a keyword %s\n",yytext); return (IF);}
else {printf("It is a keyword %s\n",yytext); return (ELSE);}
switch {printf("It is a keyword %s\n",yytext); return (SWITCH);}
case {printf("It is a keyword %s\n",yytext); return (CASE);}
for {printf("It is a keyword %s\n",yytext); return (FOR);}
break {printf("It is a keyword %s\n",yytext); return (BREAK);}
continue {printf("It is a keyword %s\n",yytext); return (CONTINUE);}
Template {printf("It is a keyword %s\n",yytext); return (TEMPLATE);}
struct {printf("It is a keyword %s\n",yytext); return (STRUCT);}
static {printf("It is a keyword %s\n",yytext); return (STATIC);}
#include {printf("It is a keyword %s\n",yytext); return (INCLUDE);}
#define {printf("It is a keyword %s\n",yytext); return (DEFINE);}
return {printf("It is a keyword %s\n",yytext); return (RETURN);}
[ \t\n] {}
[a-zA-Z_][a-zA-Z0-9_]* {printf("It is a identifier %s\n",yytext); return IDENTIFIER;}
[0-9]+\.[0-9]* {printf("It is a literal double %s\n",yytext); return LDOUBLE;}
[0-9]+ {printf("It is a literl integer %s\n",yytext); return LINTEGER;}
"&&" {printf("It is a logical AND %s\n",yytext); return (BOOLAND);}
"||" {printf("It is a logical OR %s\n",yytext); return (BOOLOR);}
"!" {printf("It is a logical NOT %s\n",yytext); return BOOLNOT;}
"=" {printf("It is a assignment %s\n",yytext); return (ASSIGN);}
"==" {printf("It is a relop equalence %s\n",yytext); return (EQ);}
"!=" {printf("It is a relop not equal %s\n",yytext); return (NE);}
"<" {printf("It is a relop less %s\n",yytext); return (LT);}
"<=" {printf("It is a relop less equal %s\n",yytext); return (LE);}
">" {printf("It is a greater %s\n",yytext); return (GT);}
">=" {printf("It is a greater equal %s\n",yytext); return (GE);}
"(" {printf("It is a left parenthese %s\n",yytext); return (LPAREN);}
")" {printf("It is a right parenthese %s\n",yytext); return (RPAREN);}
"{" {printf("It is a left brace %s\n",yytext); return (LBRACE);}
"}" {printf("It is a right brace %s\n",yytext); return (RBRACE);}
"." {printf("It is a dot %s\n",yytext); return (DOT);}
"," {printf("It is a comma %s\n",yytext); return (COMMA);}
"+" {printf("It is a plus sign %s\n",yytext); return (PLUS);}
"-" {printf("It is a minus sign %s\n",yytext); return (MINUS);}
"*" {printf("It is a multiple sign %s\n",yytext); return (MUL);}
"/" {printf("It is a division sign %s\n",yytext); return (DIV);}
"|" {printf("It is a bit or %s\n",yytext); return (BITOR);}
"^" {printf("It is a bit xor %s\n",yytext); return (BITXOR);}
"~" {printf("It is a bit not %s\n",yytext); return (BITNOT);}
"&" {printf("It is a bit and %s\n",yytext); return (BITAND);}
"::" {printf("It is a keyword %s\n",yytext); return (DOUBLECOLON);}
"->" {printf("It is a arrow %s\n",yytext); return ARROW;}
"//" {printf("It is a annotation %s\n",yytext); return ANNOTATION;}
"%" {printf("It is a percentage %s\n",yytext); return ADDR;}
"\"" {printf("It is a double quote %s\n",yytext); return SQUOTE;}
"\'" {printf("It is a single quote %s\n",yytext); return DQUOTE;}
":" {printf("It is a colon %s\n",yytext); return (COLON);}
";" {printf("It is a semicolon %s\n",yytext); return (SEMICOLON);}
. {printf("Unknown token!\n"); yyterminate(); }
%%
int yywrap(void){
return 0;
}
int main(int argc,char* argv[]){
argc--;
argc++;
while(1)
yylex();
return 0;
}
来源：https://www.cnblogs.com/heracles123/archive/2013/04/09/3010776.html