#define 定义 arg_list
时间: 2023-09-20 20:13:28 浏览: 54
`#define` 是 C/C++ 中的预处理器指令,用于定义一个宏。宏是一个被预处理器处理的文本替换。它可以用来定义常量、函数或任何可以用文本表示的东西。
`arg_list` 是一个标识符,它可以是任何合法的标识符,表示这个宏定义了一个带有参数列表的宏。在定义 `arg_list` 时,需要指定参数列表,例如:
```
#define MACRO_NAME(arg1, arg2, ...) do_something(arg1, arg2, ##__VA_ARGS__)
```
这个宏定义了一个名为 `MACRO_NAME` 的宏,它可以接受任意数量的参数。在这个宏中,`arg1` 和 `arg2` 是必选参数,`__VA_ARGS__` 表示可变参数列表。`##` 表示可变参数列表前面的逗号不需要输入参数时会被移除。这个宏可以在代码中使用,例如:
```
MACRO_NAME(arg1_val, arg2_val, arg3_val, arg4_val)
```
在预处理阶段,这个宏会被替换成 `do_something(arg1_val, arg2_val, arg3_val, arg4_val)`,从而达到代码复用的目的。
相关问题
controller_list: - name: fake_manipulator_controller type: $(arg fake_execution_type) joints: - JOINT1 - JOINT2 - JOINT3 - JOINT4 - JOINT5 - JOINT6 - name: fake_gripper_controller type: $(arg fake_execution_type) joints: [] initial: # Define initial robot poses per group - group: manipulator pose: home
这是一个机器人控制器列表,包括两个控制器:fake_manipulator_controller和fake_gripper_controller。每个控制器都有一个类型(fake_execution_type)和一组关节(joints)。fake_manipulator_controller还有6个关节,而fake_gripper_controller没有任何关节。在初始位置方面,该文件定义了一个manipulator组的home位置。
使用lex,yacc实现C语言的词法分析、语法分析,最后输出抽象语法树(AST),不要求typedef,#define复杂语法,给出完整详细的lex代码和yacc代码
本问题所需的代码较为复杂,无法在此处全部展示。以下是一个简化版本,供参考:
1. Lex代码:
```
%{
#include <stdio.h>
#include <stdlib.h>
#include "y.tab.h"
%}
%%
"int" { return INT; }
"float" { return FLOAT; }
"char" { return CHAR; }
"double" { return DOUBLE; }
"if" { return IF; }
"else" { return ELSE; }
"while" { return WHILE; }
"for" { return FOR; }
"do" { return DO; }
"return" { return RETURN; }
[0-9]+ { yylval.num = atoi(yytext); return NUM; }
[a-zA-Z_][a-zA-Z0-9_]* { yylval.str = strdup(yytext); return ID; }
"==" { return EQ; }
"!=" { return NE; }
">=" { return GE; }
"<=" { return LE; }
">" { return GT; }
"<" { return LT; }
"=" { return ASSGN; }
"+" { return PLUS; }
"-" { return MINUS; }
"*" { return MULT; }
"/" { return DIV; }
"%" { return MOD; }
"(" { return LPAREN; }
")" { return RPAREN; }
"{" { return LBRACE; }
"}" { return RBRACE; }
";" { return SEMICOLON; }
"," { return COMMA; }
"[" { return LBRACKET; }
"]" { return RBRACKET; }
"'" { return SQUOTE; }
\" { return DQUOTE; }
[ \t\n] ; /* ignore white space */
. { printf("Unknown token: %s\n", yytext); }
%%
int yywrap() {
return 1;
}
```
2. Yacc代码:
```
%{
#include <stdio.h>
#include <stdlib.h>
#include "tree.h"
%}
%union {
int num;
char *str;
Node *node;
}
%token <num> NUM
%token <str> ID
%token INT FLOAT CHAR DOUBLE IF ELSE WHILE FOR DO RETURN
%token EQ NE GE LE GT LT ASSGN PLUS MINUS MULT DIV MOD LPAREN RPAREN LBRACE RBRACE SEMICOLON COMMA LBRACKET RBRACKET SQUOTE DQUOTE
%type <node> program decl_list decl var_list var stmt_list stmt expr term factor
%start program
%%
program: decl_list {
$$ = create_node(PROGRAM, $1, NULL, NULL);
}
decl_list: /* empty */ {
$$ = NULL;
}
| decl_list decl {
$$ = create_node(DECL_LIST, $1, $2, NULL);
}
decl: type var_list SEMICOLON {
$$ = create_node(DECL, $1, $2, NULL);
}
type: INT {
$$ = create_node(TYPE, "int", NULL, NULL);
}
| FLOAT {
$$ = create_node(TYPE, "float", NULL, NULL);
}
| CHAR {
$$ = create_node(TYPE, "char", NULL, NULL);
}
| DOUBLE {
$$ = create_node(TYPE, "double", NULL, NULL);
}
var_list: var {
$$ = create_node(VAR_LIST, $1, NULL, NULL);
}
| var_list COMMA var {
$$ = create_node(VAR_LIST, $1, $3, NULL);
}
var: ID {
$$ = create_node(VAR, $1, NULL, NULL);
}
| ID LBRACKET NUM RBRACKET {
$$ = create_node(VAR, $1, create_node(NUMBER, $3, NULL, NULL), NULL);
}
stmt_list: /* empty */ {
$$ = NULL;
}
| stmt_list stmt {
$$ = create_node(STMT_LIST, $1, $2, NULL);
}
stmt: expr SEMICOLON {
$$ = create_node(EXPR_STMT, $1, NULL, NULL);
}
| LBRACE stmt_list RBRACE {
$$ = create_node(BLOCK, $2, NULL, NULL);
}
| IF LPAREN expr RPAREN stmt {
$$ = create_node(IF_STMT, $3, $5, NULL);
}
| IF LPAREN expr RPAREN stmt ELSE stmt {
$$ = create_node(IF_ELSE_STMT, $3, $5, $7);
}
| WHILE LPAREN expr RPAREN stmt {
$$ = create_node(WHILE_STMT, $3, $5, NULL);
}
| FOR LPAREN expr SEMICOLON expr SEMICOLON expr RPAREN stmt {
$$ = create_node(FOR_STMT, create_node(EXPR_STMT, $3, NULL, NULL), create_node(EXPR_STMT, $5, NULL, NULL), create_node(EXPR_STMT, $7, NULL, NULL), $9);
}
| DO stmt WHILE LPAREN expr RPAREN SEMICOLON {
$$ = create_node(DO_WHILE_STMT, $4, $2, NULL);
}
| RETURN expr SEMICOLON {
$$ = create_node(RETURN_STMT, $2, NULL, NULL);
}
expr: term {
$$ = create_node(EXPR, $1, NULL, NULL);
}
| expr PLUS term {
$$ = create_node(PLUS_EXPR, $1, $3, NULL);
}
| expr MINUS term {
$$ = create_node(MINUS_EXPR, $1, $3, NULL);
}
term: factor {
$$ = create_node(TERM, $1, NULL, NULL);
}
| term MULT factor {
$$ = create_node(MULT_TERM, $1, $3, NULL);
}
| term DIV factor {
$$ = create_node(DIV_TERM, $1, $3, NULL);
}
| term MOD factor {
$$ = create_node(MOD_TERM, $1, $3, NULL);
}
factor: NUM {
$$ = create_node(NUMBER, $1, NULL, NULL);
}
| ID {
$$ = create_node(IDENTIFIER, $1, NULL, NULL);
}
| ID LBRACKET expr RBRACKET {
$$ = create_node(ARRAY_ACCESS, $1, $3, NULL);
}
| LPAREN expr RPAREN {
$$ = create_node(EXPR, $2, NULL, NULL);
}
| MINUS factor {
$$ = create_node(NEG_FACTOR, $2, NULL, NULL);
}
| factor PLUS PLUS {
$$ = create_node(POST_INC_FACTOR, $1, NULL, NULL);
}
| factor MINUS MINUS {
$$ = create_node(POST_DEC_FACTOR, $1, NULL, NULL);
}
| SQUOTE ID SQUOTE {
$$ = create_node(CHARACTER, $2, NULL, NULL);
}
| DQUOTE ID DQUOTE {
$$ = create_node(STRING, $2, NULL, NULL);
}
| func_call {
$$ = create_node(EXPR_STMT, $1, NULL, NULL);
}
func_call: ID LPAREN arg_list RPAREN {
$$ = create_node(FUNC_CALL, $1, $3, NULL);
}
arg_list: /* empty */ {
$$ = NULL;
}
| expr {
$$ = create_node(ARG_LIST, $1, NULL, NULL);
}
| arg_list COMMA expr {
$$ = create_node(ARG_LIST, $1, $3, NULL);
}
%%
int yylex();
void yyerror(char *);
int main() {
yyparse();
return 0;
}
void yyerror(char *s) {
printf("%s\n", s);
}
```
以上代码演示了如何使用lex和yacc实现C语言的词法分析、语法分析,并输出抽象语法树。具体实现中还需要定义Node结构体和相关的操作函数,以及将yacc生成的AST传递到下一步的代码生成中。