我试图为Csimple构建一个编译器。当我运行命令 “cc -o test y.tab.c -ll -L.y”我遇到了一道错误。 我很茫然。 我知道我的yacc文件解析得不好， 但首先我需要它运行所以我可以看到输出。 yacc文件中间的行“％{”出现错误。
法：
func gestureRecognizer(gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWithGestureRecognizer otherGestureRecognizer: UIGestureRecognizer) -> Bool {
return true
}
YACC：
%option yylineno
%pointer
%{
#include <stdlib.h>
#include <string.h>
void yyerror(const char *);
%}
low \_
identifier {letters}{digit}*{low}{letters}|{letters}
stringERR {doubleQuotes}{doubleQuotes}+|{doubleQuotes}
charERR {singleQuotes}+{digits}*{letters}*{singleQuotes}+
ERR {charERR}|{stringERR}
type boolean|string|char|integer|intptr|charptr|var
dbland "&&"
devide "/"
assign "="
equal "=="
greater ">"
lesser "<"
greaterequal ">="
lesserequal "<="
minus "-"
plus "+"
not "!"
notequal "!="
or "||"
multiply "*"
power "^"
AND "&"
literBool true|false
letter [a-z]|[A-Z]
letters {letter}+
singleQuotes '
literChar {singleQuotes}{letter}{singleQuotes}
digit [0-9]
digitZero 0
octalDigit [1-7]
octal {digitZero}{octalDigit}{digitZero}*{octalDigit}*
digits {digit}+
digitNoZero[1-9]
decimal {digit}|{digitNoZero}{digits}
hexLetter A|B|C|D|E|F
hex 0(x|X){digit}+{hexLetter}*|0(x|X){digit}*{hexLetter}+
letterB b
digitOne 1
binaryInt ({digitZero}|{digitOne})+{letterB}
integer {binaryInt}|{hex}|{octal}|{decimal}
doubleQuotes \"
ltrlString {doubleQuotes}{letters}*{decimal}*{hex}*{octal}*{binaryInt}*{dbland}*{devide}*{assign}*{equal}*{greater}*{lesser}*{greaterequal}*{lesserequal}*{minus}*{plus}*{not}*{notequal}*{or}*{multiply}*{AND}*{power}*{doubleQuotes}
comment {backslash}{parcent}{space}*({letters}*{space}*{identifier}*{space}*{decimal}*{space}*{hex}*{space}*{octal}*{space}*{binaryInt}*{space}*{dbland}*{devide}*{assign}*{equal}*{greater}*{lesser}*{greaterequal}*{lesserequal}*{minus}*{p$us}*{plus}*{not}*{notequal}*{or}*{multiply}*{AND}*{power}*{ltrlString}*)*{space}{parcent}{backslash}
colon ":"
openSq "["
closeSq "]"
semicolon ";"
parcent "%"
space " "
comma ","
backslash "/"
clos ")"
opn "("
charptr charptr
pointer {colon}{space}{charptr}|"="{space}"&"{identifier}
pointerErr "&"{identifier}|{charptr}
ELSE "else"{space}*
statif "if"{space}*
whileLoop "while"{space}*
returnState "return"{space}*
func "procedure"{space}*
%%
{dbland} return dbland;
{devide} return devide;
{assign} return assign;
{equal} return equal;
{greater} return greater;
{greaterequal} return greaterequal;
{lesserequal} return lesserequal;
{minus} return minus;
{plus} return plus;
{not} return not;
{notequal} return notequal;
{or} return or;
{multiply} return multiply;
{power} return power;
{AND} return AND;
{literBool} return literBool;
{literChar} return literChar;
{decimal} return decimal;
{hex} return hex;
{octal} return octal;
{binaryInt} return binaryInt;
{ltrlString} return ltrlString
{type} return type;
{identifier} return identifier;
{ERR} return ERR;
{comment} return comment;
{pointer} return pointer;
{pointerErr} return pointerErr;
{statif} return statif;
{ELSE} return ELSE;
{whileLoop} return whileLoop;
{returnState} return returnState;
{func} return func;
{semicolon} return semicolon;
{comma} return comma;
[\*\(\)\.\+\-\%] { return *yytext; }
[0-9][0-9]* { return 'n'; }
[ \t\n] ; /* skip whitespace */
%%
int yywrap(void) {
return 1;
}
执行：
%token low identifier stringERR charERR ERR type operator literBool letter
%token dbland literChar decimal hex octal integer
%token binaryInt ltrString comment pointer pointerErr
%token statif ELSE whileLoop returnState func comma semicolon
%token EOL LPAREN RPAREN UMINUS
%left equal greater notequal lesser greaterequal lesserequal
%left '|' %left '&' %left SHIFT /* << >> */
%left minus plus
%left multiply devide '%' MOD %left power
%left not or AND comma
%nonassoc UMINUS
%%
s: BLOCK;
BLOCK: expr|logicOp|varible_declaration|ifExp|whileExp|procExp|semicolon;
expr: exp{printtree($1);}
exp:
identifier {$$=mknode(yytext,NULL,NULL);}
| LPAREN expr RPAREN {$$=$2;}
| exp plus exp {$$= mknode("+" $1,$3);}
| exp minus exp {$$= mknode("-" $1, $3);}
| exp multiply exp {$$=mknode("*" $1, $3);}
| exp devide exp {$$=mknode("/" $1, $3);}
| "-" exp %prec UMINUS {-$2}
varible_declaration: var{printtree($1);}
var : "VAR" identifier_list ":" typet ";" {$$ = mknode("var", $2, $4);}
typet:
integer{$$ = mknode(yytext,NULL,NULL);}
|binaryInt {$$ = mknode(yytext,NULL,NULL);}
|type {$$ = mknode(yytext,NULL,NULL);}
identifier_list: identifier_list comma identifier_list
{$$= mknode(",",$1, $3);}
|identifier {$$ = mknode(yytext,NULL,NULL);}
logicOp: op{printtree($1);}
op:exp equal exp {$$ = mknode("==",$1,$3);}
|exp notequal exp {$$ = mknode("!=",$1,$3);}
|exp or exp {$$ = mknode("||",$1,$3);}
|exp AND exp {$$ = mknode("&&",$1,$3);}
|exp greater exp {$$ = mknode(">",$1,$3);}
|exp greaterequal exp {$$ = mknode(">=",$1,$3);}
|exp lesser exp {$$ = mknode("<",$1,$3);}
|exp lesserequal exp {$$ = mknode("<=",$1,$3);}
ifExp: if{printtree($1);}
if:statif '(' logicOp ')' '{' BLOCK '}' ELSE '{' BLOCK '}' {$$ = mknode("if",$3,mknode("else",$6,$10));}
|statif '(' logicOp ')' '{' BLOCK '}' {$$=mknode("if",$3,$6);}
whileExp: while{printtree($1)}
while:whileLoop '(' logicOp ')' '{' BLOCK '}' {$$=mknode("while",$3,$6);}
procExp: proc{printtree($1)}
proc:func identifier '(' identifier_list ')' returnState type '{' BLOCK '}' {$$ = mknode("procedure",$2,"TODO");}
%%
%{
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define YYDEBUG 1
int yylex(void);
void yyerror(const char *);
tyepdef struct node{char * token;
struct node *left;
struct node *right;
}node;
node * mknode(char * token , node * left,node * right);
void printtree(node * tree);
%}
#define yySType struct node *
#include "lex.yy.c"
main()
{ return yyparse(); }
nose * mknode(char * token,node * left, node * right)
{
node * newnode = (node*)malloc(sizeof(node));
char 8 newstr = (char*)malloc(sizeof(token)+1);
strcpy("newstr,token");
newnode->left=left;
newnode->right=right;
newnode->token=newstr;
}return newnode;
void printtree(node * tree)
{
printf("%s\n",tree->token);
if (tree->left) printtree(tree->left);
if (tree->right) printtree(tree->left);
}
extern int yylineno;
void yyerror(const char *s)
{
fprintf(stderr, "%s at line %d\n", s, yylineno);
return;
}
这就是故障发生的地方。
正如我所说，我得到了很多错误，但第一个错误 test.y：60：错误：预期标识符或'（''''''''''''''''''''''''''
答案 0 :(得分：0)
像%{这样的Yacc指令只能出现在yacc文件的FIRST部分（第一个%%之前），除了少数几个可以在第二个{第一个{之前} {1}}）。第三部分（在第二个%%之后）只是将 verbatim 复制到输出y.tab.c文件中，因此除了C代码之外不能有任何其他内容。
看起来您只想在输出中使用该代码，因此只需删除第三部分中的%%和%{行。然后，只需检查从编译器获得的每个错误或警告（并执行使用%}）并找出他们说的内容以及如何解决它们。