Solidity邮件正则合约编译报错：Expected ',' but got identifier求助

错误原因分析 #

编译报错ParserError: Expected ',' but got identifier出现在cur = state(cur).func(uint c);行，核心问题有两个：

1. 结构体函数类型声明不匹配且语法错误：结构体State中func的类型声明为function (byte) internal pure returns (uint)，但实际所有状态处理函数（s1-s10）接收的是uint8参数，且Solidity 0.5.x要求函数类型的参数列表必须严格匹配，不能有语法冗余。
2. 函数调用时不必要的类型转换：调用func时对uint8类型的c做uint转换，既多余又触发语法解析错误。

修正步骤 #

1. 修正结构体函数类型 #

将State结构体中的func类型改为与实际函数匹配的uint8参数类型：

struct State {
  bool accepts;
  function(uint8) internal pure returns (uint) func;
}

2. 修正函数调用语句 #

在matches函数中，直接传递uint8类型的c参数，去掉多余的类型转换：

cur = state(cur).func(c);

完整修正后的合约代码 #

// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.4.22 <0.9.0;

library EmailRegex {
  struct State {
    bool accepts;
    function(uint8) internal pure returns (uint) func;
  }

  function state(uint  id) internal pure returns (State memory) {
    if (id == 1) {
      return State(false, s1);
    }
    if (id == 2) {
      return State(false, s2);
    }
    if (id == 3) {
      return State(false, s3);
    }
    if (id == 4) {
      return State(false, s4);
    }
    if (id == 5) {
      return State(false, s5);
    }
    if (id == 6) {
      return State(false, s6);
    }
    if (id == 7) {
      return State(false, s7);
    }
    if (id == 8) {
      return State(false, s8);
    }
    if (id == 9) {
      return State(true, s9);
    }
    if (id == 10) {
      return State(true, s10);
    }
    // 添加默认返回，避免无匹配时的编译警告
    return State(false, s1);
  }

  function matches(string memory input) public pure returns (bool) {
    uint cur = 1;

    for (uint i = 0; i < bytes(input).length; i++) {
      uint8 c = uint8(bytes(input)[i]);

      cur = state(cur).func(c);
      if (cur == 0) {
        return false;
      }
    }

    return state(cur).accepts;
  }

  function s1(uint8  c) internal pure returns (uint) {
    if (c == 37 || c == 43 || c == 45 || c == 46 || c == 57 || c >= 65 && c <= 90 || c == 95 || c >= 97 && c <= 122) {
      return 2;
    }

    return 0;
  }

  function s2(uint8  c)  internal pure  returns (uint) {
    if (c == 37 || c == 43 || c == 45 || c == 46 || c >= 48 && c <= 57 || c >= 65 && c <= 90 || c == 95 || c >= 97 && c <= 122) {
      return 3;
    }
    if (c == 64) {
      return 4;
    }

    return 0;
  }

  function s3(uint8  c)  internal pure returns (uint) {
    if (c == 37 || c == 43 || c == 45 || c == 46 || c >= 48 && c <= 57 || c >= 65 && c <= 90 || c == 95 || c >= 97 && c <= 122) {
      return 3;
    }
    if (c == 64) {
      return 4;
    }

    return 0;
  }

  function s4(uint8  c) internal pure returns (uint) {
    if (c >= 46 && c <= 47 || c >= 48 && c <= 57 || c >= 58 && c <= 64 || c >= 65 && c <= 90 || c >= 91 && c <= 95 || c >= 97 && c <= 122) {
      return 5;
    }

    return 0;
  }

  function s5(uint8  c) internal pure returns (uint) {
    if (c == 46) {
      return 6;
    }
    if (c == 47 || c >= 48 && c <= 57 || c >= 58 && c <= 64 || c >= 65 && c <= 90 || c >= 91 && c <= 95 || c >= 97 && c <= 122) {
      return 7;
    }

    return 0;
  }

  function s6(uint8  c) internal pure returns (uint) {
    if (c == 46) {
      return 6;
    }
    if (c == 47 || c >= 48 && c <= 57 || c >= 58 && c <= 64 || c >= 91 && c <= 95) {
      return 7;
    }
    if (c >= 65 && c <= 90 || c >= 97 && c <= 122) {
      return 8;
    }

    return 0;
  }

  function s7(uint8  c) internal pure returns (uint) {
    if (c == 46) {
      return 6;
    }
    if (c == 47 || c >= 48 && c <= 57 || c >= 58 && c <= 64 || c >= 65 && c <= 90 || c >= 91 && c <= 95 || c >= 97 && c <= 122) {
      return 7;
    }

    return 0;
  }

  function s8(uint8  c) internal pure returns (uint) {
    if (c == 46) {
      return 6;
    }
    if (c == 47 || c >= 48 && c <= 57 || c >= 58 && c <= 64 || c >= 91 && c <= 95) {
      return 7;
    }
    if (c >= 65 && c <= 90 || c >= 97 && c <= 122) {
      return 9;
    }

    return 0;
  }

  function s9(uint8  c) internal pure returns (uint) {
    if (c == 46) {
      return 6;
    }
    if (c == 47 || c >= 48 && c <= 57 || c >= 58 && c <= 64 || c >= 91 && c <= 95) {
      return 7;
    }
    if (c >= 65 && c <= 90 || c >= 97 && c <= 122) {
      return 10;
    }

    return 0;
  }

  function s10(uint8  c) internal pure returns (uint) {
    if (c == 46) {
      return 6;
    }
    if (c == 47 || c >= 48 && c <= 57 || c >= 58 && c <= 64 || c >= 91 && c <= 95) {
      return 7;
    }
    if (c >= 65 && c <= 90 || c >= 97 && c <= 122) {
      return 10;
    }

    return 0;
  }
}

验证 #

将修正后的代码替换原合约，使用你当前的环境（Truffle v5.5.21、Solidity v0.5.16）编译，即可通过编译。

内容的提问来源于stack exchange，提问作者user14487732