Question

我正在使用类似于C语言的解析器。我对语句expression有疑问。

我在很多帖子上看到他们如何表达这种表达方式，但对我来说它并不起作用......我有很多冲突。你能帮帮我吗？

.y档案：

%{ 
    #include <stdio.h> 
    #include <stdlib.h>
    extern FILE *yyin; 
    extern int yylex(); 
    int line=1; 
    int error=0; 
    #define YYERROR_VERBOSE 

    void yyerror(const char *msg) 
    { 
        error = 1; 
        printf("ERROR in line %d : %s.\n", line, msg); 
    } 
%}

%expect 2
%start programme
%token SEMICOLON
%token COMMA
%token L_PARENTHESIS
%token R_PARENTHESIS
%token L_REC_BRACKET
%token R_REC_BRACKET
%token L_CURLY_BRACKET
%token R_CURLY_BRACKET
%token QUESTION_MARK
%token COLON
%token DOT
%token AND
%token STAR
%token PLUS
%token MINUS
%token EXCLAMATION_MARK
%token SLASH
%token PERCENT
%token LESS
%token GREATER
%token LESS_EQUAL
%token GREATER_EQUAL
%token EQUAL
%token NOT_EQUAL
%token LOGIC_AND
%token LOGIC_OR
%token UN_PLUS
%token UN_MINUS
%token EQ
%token MUL_EQUAL
%token DIV_EQUAL
%token MOD_EQUAL
%token PLUS_EQUAL
%token MINUS_EQUAL
%token TRUE
%token FALSE
%token NUL
%token NUMBER
%token T_WORD
%token WORD


    %right L_PARENTHESIS SEMICOLON
%nonassoc STAR 
%right SLASH PERCENT PLUS MINUS LESS GREATER 
%right LESS_EQUAL GREATER_EQUAL EQUAL NOT_EQUAL LOGIC_AND LOGIC_OR          
%right UN_PLUS UN_MINUS              
%right AND EXCLAMATION_MARK        
%right EQ MUL_EQUAL DIV_EQUAL MOD_EQUAL PLUS_EQUAL MINUS_EQUAL

%%

programme : expression;
expression : TRUE 
           | FALSE 
           | NUL               
           | id L_PARENTHESIS list_exp R_PARENTHESIS 
           | expression L_REC_BRACKET expression R_REC_BRACKET
           | unitary_op expression
           | expression binary_op exp
           | unitary_op_assig expression
           | expression unitary_op_assig
           | expression binary_op_assig expression  
           | expression QUESTION_MARK expression COLON expression
           | exp
           | DELETE expression
;
exp : T_WORD 
    | id
    | L_PARENTHESIS expression R_PARENTHESIS
    | double_const;
id: WORD;
list_exp : list expression; 

list: | list_exp COMMA;

int_const : NUMBER int_const
          | NUMBER;

double_const : int_const 
             | int_const DOT int_const;

binary_op : STAR
          | SLASH
          | PERCENT
          | PLUS
          | MINUS
          | LESS
          | GREATER
          | LESS_EQUAL
          | GREATER_EQUAL
          | EQUAL
          | NOT_EQUAL
          | LOGIC_AND
          | LOGIC_OR;

unitary_op_assig : UN_PLUS
                 | UN_MINUS;

unitary_op : AND
           | STAR
           | PLUS
           | MINUS
           | EXCLAMATION_MARK;

binary_op_assig : EQ
                | MUL_EQUAL
                | DIV_EQUAL
                | MOD_EQUAL
                | PLUS_EQUAL
                | MINUS_EQUAL;

%%

int main(int argc, char *argv[])
{       
    if(argc == 2) yyin = fopen(argv[1], "r");
    else if(argc < 2){
        printf("No file found.\n");
        return 0;
    } else{
         printf("Only one file is permitted.\n");
        return 0;
    }

    yyparse ();
    if(error == 0) printf("Finished at %d line. No errors!\n",line); 
    return 0; 
}

.l文件

%{
    #include <stdio.h>
    #include <string.h>
    #include <stdlib.h>
    #include "bison.tab.h"
    extern int line;
%}

%%

"\n" {line++;}

";" {return SEMICOLON;}

"," {return COMMA;} 

"(" {return L_PARENTHESIS;}

")" {return R_PARENTHESIS;}

"[" {return L_REC_BRACKET;}

"]" {return R_REC_BRACKET;} 

"{" {return L_CURLY_BRACKET;}

"}" {return R_CURLY_BRACKET;}

"?" {return QUESTION_MARK;}

":" {return COLON;}

"." {return DOT;}

"&" {return AND;}

"*" {return STAR;}

"+" {return PLUS;}

"-" {return MINUS;}

"!" {return EXCLAMATION_MARK;}

"/" {return SLASH;}

"%" {return PERCENT;}

"<" {return LESS;}

">" {return GREATER;}

"<=" {return LESS_EQUAL;}

">=" {return GREATER_EQUAL;}

"==" {return EQUAL;}

"!=" {return NOT_EQUAL;}

"&&" {return LOGIC_AND;}

"||" {return LOGIC_OR;}

"++" {return UN_PLUS;}

"--" {return UN_MINUS;}

"=" {return EQ;}

"*=" {return MUL_EQUAL;}

"/=" {return DIV_EQUAL;}

"%=" {return MOD_EQUAL;}

"+=" {return PLUS_EQUAL;}

"-=" {return MINUS_EQUAL;}

"true" {return TRUE;}

"false" {return FALSE;}

"NULL" {return NUL;}

[0-9] {return NUMBER;}

[a-zA-Z][a-zA-Z0-9]* {return WORD;}

[a-zA-Z0-9]+ {return T_WORD;}

. {;}

%%

使用bison -d bison.y我收到消息：conflicts: (a number) shift/reduce conflicts。

例如我与bison -v bison.y：

state 71

   54 expression: expression . L_REC_BRACKET expression R_REC_BRACKET
   58           | expression . unitary_op_assig
   59           | expression . binary_op_assig expression
   61           | expression . QUESTION_MARK expression COLON expression
   64           | DELETE expression .

    L_REC_BRACKET  shift, and go to state 75
    QUESTION_MARK  shift, and go to state 76
    UN_PLUS        shift, and go to state 43
    UN_MINUS       shift, and go to state 44
    EQ             shift, and go to state 77
    MUL_EQUAL      shift, and go to state 78
    DIV_EQUAL      shift, and go to state 79
    MOD_EQUAL      shift, and go to state 80
    PLUS_EQUAL     shift, and go to state 81
    MINUS_EQUAL    shift, and go to state 82

    L_REC_BRACKET  [reduce using rule 64 (expression)]
    QUESTION_MARK  [reduce using rule 64 (expression)]
    UN_PLUS        [reduce using rule 64 (expression)]
    UN_MINUS       [reduce using rule 64 (expression)]
    EQ             [reduce using rule 64 (expression)]
    MUL_EQUAL      [reduce using rule 64 (expression)]
    DIV_EQUAL      [reduce using rule 64 (expression)]
    MOD_EQUAL      [reduce using rule 64 (expression)]
    PLUS_EQUAL     [reduce using rule 64 (expression)]
    MINUS_EQUAL    [reduce using rule 64 (expression)]
    $default       reduce using rule 64 (expression)

    unitary_op_assig  go to state 83
    binary_op_assig   go to state 84

表达野牛的冲突

0 个答案: