野牛零或语法文件一个出现

Question

我需要解析一个JSON对象一样，但{"f": 1, "i": 2, "g": 5, ...}定期不像JSON对象，输入可以在对象具有零个或一个...

所以，这是错了对象{"f": 1, "f": 1, "i": 2, ...}，因为它有“f两次”的关键。

而且，这个对象很好{"i": 2}，因为它只是关键“我”，它不会出现一次以上。

这是我试过的。我知道它不起作用，但我不知道如何设定它是正确的。

RuleMemberList 
    : RuleMember 
     {{$$ = {}; $$[$1[0]] = $1[1];}} 
    | RuleMemberList ',' RuleMember 
     {$$ = $1; $1[$3[0]] = $3[1];} 
    ; 

RuleMember 
    : I ':' RuleString 
      {$$ = [$1, $3];} 
    | G ':' RuleString 
      {$$ = [$1, $3];} 
    | F ':' RuleFinder 
      {$$ = [$1, $3];} 
    | A ':' RuleAction 
      {$$ = [$1, $3];} 
    | T ':' RuleTarget 
      {$$ = [$1, $3];} 
    | P ':' RuleNumber 
      {$$ = [$1, $3];} 
    | C ':' RuleChance 
      {$$ = [$1, $3];} 
    | L ':' RuleLayers 
      {$$ = [$1, $3];} 
    | R ':' RuleString 
      {$$ = [$1, $3];} 
    | E ':' RuleEvents 
      {$$ = [$1, $3];} 
    | B ':' RuleBinds 
      {$$ = [$1, $3];} 
    ; 

我可以将它定义为零或某种情况吗？

Answer 1

将元素添加到地图时检查重复项。例如：

| RuleMemberList ',' RuleMember 
    { $$ = $1; 
     if ($3[0] in $1) 
     error("duplicate key ", $3[0], " in map"); 
     else 
     $1[$3[0]] = $3[1];} 
;