Method tokenize

calc/calc.ts:32–87

(expr: string)

    "*": { precedence: 2 },
    "/": { precedence: 2 },
  };

  private static tokenize(expr: string): string[] {
    const cleaned = expr.replace(/\s+/g, "");
    if (!cleaned) {
      throw new Error("表达式为空");
    }
    if (!/^[0-9+\-*/().]+$/.test(cleaned)) {
      throw new Error("表达式包含不支持的字符");
    }

    const tokens: string[] = [];
    let current = "";

    const pushCurrent = () => {
      if (!current) return;
      if (!this.isNumber(current)) {
        throw new Error(`无效的数字: ${current}`);
      }
      tokens.push(current);
      current = "";
    };

    const isUnaryPosition = (index: number) =>
      index === 0 || cleaned[index - 1] === "(" || cleaned[index - 1] in this.operators;

    for (let i = 0; i < cleaned.length; i++) {
      const char = cleaned[i];

      if (/[0-9.]/.test(char)) {
        current += char;
        continue;
      }

      pushCurrent();

      if ((char === "-" || char === "+") && isUnaryPosition(i)) {
        if (char === "-") {
          if (i + 1 < cleaned.length && cleaned[i + 1] === "(") {
            tokens.push("-1");
            tokens.push("*");
            continue;
          }
          current = "-";
        }
        continue;
      }

      if (!(char in this.operators) && char !== "(" && char !== ")") {
        throw new Error(`未知操作符: ${char}`);
      }

      tokens.push(char);
    }

    pushCurrent();
    return tokens;
  }