Итак, в основном, я получаю синтаксическую ошибку всякий раз, когда тестирую пустой файл или файл, содержащий только комментарий.Ошибка выглядит следующим образом: 
test01 - это просто пустой файл .c
Вот мой файл Lex:
%{
/*constants are defined outside of the l file in y.tab.h
*constants are defined from 257
*/
#include "y.tab.h"
int input_line_no = 1;
char the_tokens[1000];
char full_line[1000];
int lex_state = 0;
%}
whitespace [ \t]
number [0-9]
letter [A-Za-z]
alfanum [A-Za-z0-9_]
intcon {number}+
id {letter}{alfanum}*
anything .
%option noyywrap
/*
*Start conditions are specified to identify comments,
*literal strings, and literal chars.
*/
%Start comment_in comment_out string_in char_in
%%
/*tokenization of special strings*/
"extern" {return EXTERN;}
"if" {return IF;}
"else" {return ELSE;}
"void" {return VOID;}
"char" {return CHAR;}
"int" {return INT;}
/*line number is recorded*/
[\n] input_line_no++;
/*identify comment*/
<INITIAL>"/""*" {
lex_state=1;
BEGIN(comment_in);
}
<comment_in>"*" BEGIN(comment_out);
<comment_in>[^*] ;
<comment_out>"*" ;
<comment_out>"/" {
lex_state = 0;
BEGIN(INITIAL);
}
<comment_out>[^*/] BEGIN(comment_in);
/*start tokenization of strings*/
<INITIAL>\" {
lex_state = 2;
BEGIN(string_in);
}
<string_in>[^"] {
return STRINGCON;
}
<string_in>\" {
lex_state = 0;
BEGIN(INITIAL);
}
/*tokenization of characters*/
<INITIAL>\' {
lex_state = 3;
BEGIN(char_in);
}
<char_in>[^']
{
return CHARCON;
}
<char_in>\' {
lex_state = 0;
BEGIN(INITIAL);
}
{whitespace} ;
/*tokenization of numbers*/
{intcon} {return(INTCON);}
{id} {return ID;}
/*tokenization of operations*/
"==" {return EQUALS;}
"!=" {return NOTEQU;}
">=" {return GREEQU;}
"<=" {return LESEQU;}
">" {return GREATE;}
"<" {return LESSTH;}
"&&" {return ANDCOM;}
"||" {return ORCOMP;}
"!" {return ABANG;}
";" {return SEMIC;}
"," {return COMMA;}
"(" {return LPAR;}
")" {return RPAR;}
"[" {return LBRAC;}
"]" {return RBRAC;}
"{" {return LCURL;}
"}" {return RCURL;}
"+" {return ADD;}
"-" {return SUB;}
"*" {return MUL;}
"/" {return DIV;}
"=" {return EQUAL;}
/*For strings that can not be identified by any patterns specified previously
*lex returns the value of the character
*/
{anything} {return(OTHER);}
%%
Вот мой файл Yacc:
%{
#include <stdio.h>
#define YDEBUG
#ifndef YDEBUG
#define Y_DEBUG_PRINT(x)
#else
#define Y_DEBUG_PRINT(x) printf("Yout %s \n ",x)
#endif
int yydebug = 1;
extern char the_token[];
/* This is how I read tokens from lex... :) */
extern int input_line_no;
/* This is the current line number */
extern char *full_line;
/* This is the full line */
extern int lex_state;
%}
%token STRINGCON CHARCON INTCON EQUALS NOTEQU GREEQU LESEQU GREATE LESSTH
%token ANDCOM ORCOMP SEMIC COMMA LPAR RPAR LBRAC RBRAC LCURL RCURL ABANG
%token EQUAL ADD SUB MUL DIV ID EXTERN FOR WHILE RETURN IF ELSE
%token VOID CHAR INT OTHER
%left ORCOMP
%left ANDCOM
%left EQUALS NOTEQU
%left LESSTH GREATE LESEQU GREEQU
%left ADD SUB
%left MUL DIV
%right UMINUS
%right ABANG
%start Assign
%%
prog: dcl SEMIC prog2 {Y_DEBUG_PRINT("prog-dcl-SEMIC-prog2");}
| Function prog2 {Y_DEBUG_PRINT("prog-Function-prog2");}
prog2: {Y_DEBUG_PRINT("prog2-EMPTY");}
| dcl SEMIC prog2 {Y_DEBUG_PRINT("prog2-dcl-SEMIC-prog2");}
| Function prog2 {Y_DEBUG_PRINT("prog2-Function-prog2");}
dcl: VAR_list {Y_DEBUG_PRINT("dcl-VAR_list");}
| ID LPAR Param_types RPAR dcl2 {Y_DEBUG_PRINT("dcl-ID-LPAR-Param_types-RPAR-dcl2");}
| EXTERN ID LPAR Param_types RPAR dcl2 {Y_DEBUG_PRINT("dcl-EXTERN-ID-LPAR-Param_types-RPAR-dcl2");}
| EXTERN Type ID LPAR Param_types RPAR dcl2 {Y_DEBUG_PRINT("dcl-EXTERN-Type-ID-LPAR-Param_types-RPAR-dcl2");}
| EXTERN VOID ID LPAR Param_types RPAR dcl2 {Y_DEBUG_PRINT("dcl-EXTERN-VOID-ID-LPAR-Param_types-RPAR-dcl2");}
| Type ID LPAR Param_types RPAR dcl2 {Y_DEBUG_PRINT("dcl-Type-ID-LPAR-Param_types-RPAR-dcl2");}
| VOID ID LPAR Param_types RPAR dcl2 {Y_DEBUG_PRINT("dcl-VOID-ID-LPAR-Param_types-RPAR-dcl2");}
dcl2: {Y_DEBUG_PRINT("dcl2-EMPTY");}
| COMMA ID LPAR Param_types RPAR dcl2 {Y_DEBUG_PRINT("dcl2-COMMA-ID-LPAR-Param_types-RPAR-dcl2");}
Function: Functionhead LCURL Functionbody RCURL {Y_DEBUG_PRINT("Function-Functionhead-LCURL-Functionbody-RCURL");}
| VOID Functionhead LCURL Functionbody RCURL {Y_DEBUG_PRINT("Function-VOID-Functionhead-LCURL-Functionbody-RCURL");}
| Type Functionhead LCURL Functionbody RCURL {Y_DEBUG_PRINT("Function-Type-Functionhead-LCURL-Functionbody-RCURL");}
Functionhead: ID LPAR Param_types RPAR {Y_DEBUG_PRINT("Functionhead-ID-LPAR-Param_types-RPAR");}
Functionbody: VAR_list STMT_list {Y_DEBUG_PRINT("Functionbody-Varlist-Stmtlist");}
Param_types: VOID {Y_DEBUG_PRINT("Param_types-VOID");}
|Param_types1 {Y_DEBUG_PRINT("Param_types-Param_types1");}
Param_types1: Param_type1 {Y_DEBUG_PRINT("Param_types1-Param_type1");}
| Param_types1 COMMA Param_type1 {Y_DEBUG_PRINT("Param_types1-Param_types1-COMMA-Param_type1");}
Param_type1: Type ID Param_type11 {Y_DEBUG_PRINT("PARAM_type1-Type-ID-Param_type11");}
Param_type11: {Y_DEBUG_PRINT("Param_type11-EMPTY");}
| LBRAC RBRAC {Y_DEBUG_PRINT("Param_type11-LBRAC-RBRAC");}
VAR_list: Type VAR_list2 {Y_DEBUG_PRINT("VAR_list-Type-VAR_list2");}
VAR_list2: var_decl {Y_DEBUG_PRINT("VAR_list2-var_decl");}
| var_decl COMMA VAR_list2 {Y_DEBUG_PRINT("VAR_list2-var_decl-COMMA-VAR_list2");}
var_decl: ID {Y_DEBUG_PRINT("var_decl-ID");}
| ID LBRAC INTCON RBRAC {Y_DEBUG_PRINT("var-decl-ID-LBRAC-INTCON-RBRAC");}
Type: CHAR {Y_DEBUG_PRINT("Type-CHAR");}
|INT {Y_DEBUG_PRINT("Type-INT");}
STMT_list: STMT2 {Y_DEBUG_PRINT("STMT-list-STMT2");}
STMT2: STMT {Y_DEBUG_PRINT("STMT2-STMT");}
| STMT STMT2 {Y_DEBUG_PRINT("STMT2-STMT-STMT2");}
STMT : IF LPAR Expr RPAR STMT {Y_DEBUG_PRINT("IF-LPARN-Expr-RPARN-STMT");}
| IF LPAR Expr RPAR STMT ELSE STMT{Y_DEBUG_PRINT("IF-LPARN-Expr-RPARN-STMT-ELSE-STMT");}
/*if cats) ERROR*/
| IF Expr RPAR STMT ELSE STMT {warn("STMT-IF: missing LPAR");}
/*if (cats ERROR*/
| IF LPAR Expr STMT ELSE STMT {warn("STMT-IF: missing RPAR");}
/*two elses ERROR*/
| IF LPAR Expr STMT ELSE ELSE STMT {warn(":too many elses");}
| WHILE LPAR Expr RPAR STMT{Y_DEBUG_PRINT("STMT-WHILE-LPAR-Expr-RPAR-STMT");}
/*for(c=0;c<1;c++)*/
| FOR LPAR Assign SEMIC Expr SEMIC Assign RPAR STMT {Y_DEBUG_PRINT("STMT-FOR-LPAR-Assign-SEMIC-Expr-SEMIC-Assign-RPAR-STMT");}
/*for(;c<1;c++)*/
| FOR LPAR SEMIC Expr SEMIC Assign RPAR STMT {Y_DEBUG_PRINT("STMT-FOR-LPAR-SEMIC-Expr-SEMIC-Assign-RPAR-STMT");}
/*for(;;c++)*/
| FOR LPAR SEMIC SEMIC Assign RPAR STMT {Y_DEBUG_PRINT("STMT-FOR-LPAR-SEMIC-SEMIC-Assign-RPAR-STMT");}
/*for(;;)*/
| FOR LPAR SEMIC SEMIC RPAR STMT {Y_DEBUG_PRINT("STMT-FOR-LPAR-SEMIC-SEMIC-RPAR-STMT");}
/*for(c=0;;)*/
| FOR LPAR Assign SEMIC SEMIC RPAR STMT {Y_DEBUG_PRINT("STMT-FOR-LPAR-Assign-SEMIC-SEMIC-RPAR-STMT");}
/*for(c=0;c<1;)*/
| FOR LPAR Assign SEMIC Expr SEMIC RPAR STMT {Y_DEBUG_PRINT("STMT-FOR-LPAR-Assign-SEMIC-Expr-Semic-RPAR-STMT");}
/*for(c=0;;c++)*/
| FOR LPAR Assign SEMIC SEMIC Assign RPAR STMT {Y_DEBUG_PRINT("STMT-FOR-LPAR-Assign-SEMIC-SEMIC-ASSIGN-RPAR-STMT");}
/*for(;c<1;)*/
| FOR LPAR SEMIC Expr SEMIC RPAR STMT {Y_DEBUG_PRINT("STMT-FOR-LPAR-SEMIC-Expr-SEMIC-RPAR-STMT");}
/*for() ERROR*/
| FOR LPAR RPAR STMT {warn("STMT-FOR: empty statement");}
/*for{;;;) ERROR*/
| FOR LPAR SEMIC SEMIC SEMIC RPAR {warn("STMT-FOR: too many semicolons");}
/*for;;) ERROR*/
| FOR SEMIC SEMIC RPAR STMT {warn("STMT-FOR: missing LPAR");}
/*for(;; ERROR*/
| FOR LPAR SEMIC SEMIC STMT {warn("STMT-FOR: missing RPAR");}
| RETURN Expr SEMIC {Y_DEBUG_PRINT("STMT-RETURN-Expr-SEMIC");}
| RETURN SEMIC {Y_DEBUG_PRINT("STMT-RETURN-SEMIC");}
/*return ERROR*/
| RETURN {warn("STMT-Return:missing semicolon");}
| Assign SEMIC {Y_DEBUG_PRINT("STMT-Assign-SEMIC");}
/*function call*/
| ID LPAR RPAR SEMIC {Y_DEBUG_PRINT("STMT-ID-LPAR-RPAR-SEMIC");}
| ID LPAR Expr Expr2 RPAR SEMIC {Y_DEBUG_PRINT("STMT-ID-LPAR-Expr-Expr2-RPAR-SEMIC");}
/*No semic ERROR*/
| ID LPAR Expr Expr2 RPAR {warn(":missing semicolon");}
| LCURL STMT2 RCURL {Y_DEBUG_PRINT("STMT-LCURL-STMT-RCURL");}
| LCURL RCURL {Y_DEBUG_PRINT("STMT-LCURL-RCURL");}
| SEMIC {Y_DEBUG_PRINT("STMT-SEMIC");}
Assign : ID Assign1 EQUAL Expr {Y_DEBUG_PRINT("Assign-1-ID-Assign1-EQUAL-Expr");}
/*Error no semi*/
| Assign {warn( "Assign: missing semicolon on line");}
Assign1 : {Y_DEBUG_PRINT("Assign1-1-Empty"); }
| LBRAC Expr RBRAC {Y_DEBUG_PRINT("Assign1-2-LBRAC-Expr-RBRAC"); }
| LBRAC Expr error { warn("Assign1: missing RBRAC"); }
| error Expr RBRAC { warn("Assign1: missing LBRAC"); }
| LBRAC error RBRAC { warn("Assign1: Invalid array index"); }
Expr : SUB Expr %prec UMINUS {Y_DEBUG_PRINT("Expr-1-UMINUS Expr"); }
| ABANG Expr {Y_DEBUG_PRINT("Expr-2-ANABG Expr"); }
| Expr Binop Expr {Y_DEBUG_PRINT("Expr-3-Expr-Binop-Expr"); }
| Expr Relop Expr {Y_DEBUG_PRINT("Expr-4-Expr-Binop-Expr"); }
| Expr Logop Expr {Y_DEBUG_PRINT("Expr-5-Expr-Logop-Expr"); }
| ID {Y_DEBUG_PRINT("Expr-6-ID"); }
| ID LPAR RPAR {Y_DEBUG_PRINT("Expr-ID-LPAR-RPAR");}
| ID LPAR Expr Expr2 RPAR {Y_DEBUG_PRINT("Expr-ID-LPAR-Expr-Expr2-RPAR");}
| ID LBRAC Expr RBRAC {Y_DEBUG_PRINT("Expr-ID-LBRAC-Expr-RBRAC");}
| LPAR Expr RPAR {Y_DEBUG_PRINT("Expr-7-LPARN-Expr-RPARN");}
| INTCON { Y_DEBUG_PRINT("Expr-8-INTCON"); }
| CHARCON { Y_DEBUG_PRINT("Expr-9-CHARCON"); }
| STRINGCON { Y_DEBUG_PRINT("Expr-10-STRINGCON"); }
| Array {Y_DEBUG_PRINT("Expr-11-Array"); }
| error {warn("Expr: invalid expression "); }
/*top is for no expression 2*/
Expr2: {Y_DEBUG_PRINT("Expr2-Empty");}
| COMMA Expr {Y_DEBUG_PRINT("Expr2-COMMA-Expr");}
/*recursively looks for another expression in function call (exp1,exp2,exp3,...*/
| COMMA Expr Expr2 {Y_DEBUG_PRINT("Expr2-COMMA-Expr-Expr2");}
Array :
ID LBRAC Expr RBRAC {Y_DEBUG_PRINT("Array-1-ID-LBRAC-Expr-RBRAC"); }
| ID error RBRAC {warn( "Array: invalid array expression"); }
Binop : ADD {Y_DEBUG_PRINT("Binop-1-ADD"); }
| SUB {Y_DEBUG_PRINT("Binop-2-SUB"); }
| MUL {Y_DEBUG_PRINT("Binop-3-MUL"); }
| DIV {Y_DEBUG_PRINT("Binop-4-DIV"); }
Logop : ANDCOM {Y_DEBUG_PRINT("Logop-1-ANDCOM"); }
| ORCOMP {Y_DEBUG_PRINT("Logop-2-ORCOMP"); }
Relop : EQUALS { Y_DEBUG_PRINT("Relop-1-EQUALS"); }
| NOTEQU { Y_DEBUG_PRINT("Relop-2-NOTEQU"); }
| LESEQU { Y_DEBUG_PRINT("Relop-3-LESEQU"); }
| GREEQU { Y_DEBUG_PRINT("Relop-4-GREEQU"); }
| GREATE { Y_DEBUG_PRINT("Relop-5-GREATE"); }
| LESSTH { Y_DEBUG_PRINT("Relop-6-LESSTH"); }
%%
main()
{
int result = yyparse();
if (lex_state==1) {
yyerror("End of file within a comment");
}
if (lex_state==2) {
yyerror("End of file within a string");
}
return result;
}
int yywrap(){
return 1;
}
yyerror(const char *s)
{
fprintf(stderr, "%s on line %d\n",s,input_line_no);
}
warn(char *s)
{
fprintf(stderr, "%s\n", s);
}
По сути, это должен быть лексический анализатор и парсерная часть компилятора.Я пытаюсь разобрать код из-за правил C- грамматики.Я попытался добавить правило конца файла в Lexer, но оно просто выдало ту же ошибку, что и раньше, поэтому я не думаю, что это проблема.
Есть ли способ узнать, прошел ли Lexerправильные токены парсеру?
Кроме того, мне сказали проверить файл y.output, чтобы увидеть, как исправить ошибки сдвига / уменьшения для моего синтаксического анализатора, но я посмотрел на файл и не знаю, как сказатьгде ошибки.
Я знаю, что, вероятно, есть много проблем с моим кодом Yacc, но в настоящее время я просто пытаюсь исправить эту единственную ошибку, чтобы я мог работать с другими.Спасибо за любую помощь, спасибо.