♻️ Replaced with own calculator

lib/calculator.dart

@@ -0,0 +1,539 @@
+// === 在 abstract class Expr 中添加声明 ===
+import 'dart:math' show sqrt, cos, sin, tan;
+
+abstract class Expr {
+  Expr simplify();
+
+  /// 新增：对表达式进行“求值/数值化”——尽可能把可算的部分算出来
+  Expr evaluate();
+
+  @override
+  String toString();
+
+  MulExpr operator *(Expr other) => MulExpr(this, other);
+  AddExpr operator +(Expr other) => AddExpr(this, other);
+  SubExpr operator -(Expr other) => SubExpr(this, other);
+  DivExpr operator /(Expr other) => DivExpr(this, other);
+}
+
+// === IntExpr ===
+class IntExpr extends Expr {
+  final int value;
+  IntExpr(this.value);
+
+  @override
+  Expr simplify() => this;
+
+  @override
+  Expr evaluate() => this;
+
+  @override
+  String toString() => value.toString();
+}
+
+// === DoubleExpr ===
+class DoubleExpr extends Expr {
+  final double value;
+  DoubleExpr(this.value);
+
+  @override
+  Expr simplify() => this;
+
+  @override
+  Expr evaluate() => this;
+
+  @override
+  String toString() => value.toString();
+}
+
+// === FractionExpr.evaluate ===
+class FractionExpr extends Expr {
+  final int numerator;
+  final int denominator;
+
+  FractionExpr(this.numerator, this.denominator) {
+    if (denominator == 0) throw Exception("分母不能为0");
+  }
+
+  @override
+  Expr simplify() {
+    int g = _gcd(numerator.abs(), denominator.abs());
+    int n = numerator ~/ g;
+    int d = denominator ~/ g;
+
+    // 分母负数转移到分子
+    if (d < 0) {
+      n = -n;
+      d = -d;
+    }
+
+    if (d == 1) return IntExpr(n); // 化简成整数
+    return FractionExpr(n, d);
+  }
+
+  @override
+  Expr evaluate() => simplify();
+
+  @override
+  String toString() => "$numerator/$denominator";
+}
+
+// === AddExpr.evaluate: 把可算的合并（整数、分数、以及同类 sqrt 项） ===
+class AddExpr extends Expr {
+  final Expr left, right;
+  AddExpr(this.left, this.right);
+
+  @override
+  Expr simplify() {
+    var l = left.simplify();
+    var r = right.simplify();
+
+    if (l is FractionExpr && r is FractionExpr) {
+      return FractionExpr(
+        l.numerator * r.denominator + r.numerator * l.denominator,
+        l.denominator * r.denominator,
+      ).simplify();
+    }
+    if (l is IntExpr && r is FractionExpr) {
+      return FractionExpr(
+        l.value * r.denominator + r.numerator,
+        r.denominator,
+      ).simplify();
+    }
+    if (l is FractionExpr && r is IntExpr) {
+      return FractionExpr(
+        l.numerator + r.value * l.denominator,
+        l.denominator,
+      ).simplify();
+    }
+
+    return AddExpr(l, r);
+  }
+
+  @override
+  Expr evaluate() {
+    var l = left.evaluate();
+    var r = right.evaluate();
+
+    // 纯整数相加 -> 整数
+    if (l is IntExpr && r is IntExpr) {
+      return IntExpr(l.value + r.value);
+    }
+
+    // 分数相加 / 分数与整数相加
+    if (l is FractionExpr && r is FractionExpr) {
+      return FractionExpr(
+        l.numerator * r.denominator + r.numerator * l.denominator,
+        l.denominator * r.denominator,
+      ).simplify();
+    }
+    if (l is IntExpr && r is FractionExpr) {
+      return FractionExpr(
+        l.value * r.denominator + r.numerator,
+        r.denominator,
+      ).simplify();
+    }
+    if (l is FractionExpr && r is IntExpr) {
+      return FractionExpr(
+        l.numerator + r.value * l.denominator,
+        l.denominator,
+      ).simplify();
+    }
+
+    // 合并同类的 sqrt 项: a*sqrt(X) + b*sqrt(X) = (a+b)*sqrt(X)
+    var a = _asSqrtTerm(l);
+    var b = _asSqrtTerm(r);
+    if (a != null && b != null && a.inner.toString() == b.inner.toString()) {
+      return MulExpr(IntExpr(a.coef + b.coef), SqrtExpr(a.inner)).simplify();
+    }
+
+    return AddExpr(l, r);
+  }
+
+  @override
+  String toString() => "($left + $right)";
+}
+
+// === SubExpr.evaluate 类似 AddExpr，但做减法 ===
+class SubExpr extends Expr {
+  final Expr left, right;
+  SubExpr(this.left, this.right);
+
+  @override
+  Expr simplify() {
+    var l = left.simplify();
+    var r = right.simplify();
+
+    if (l is IntExpr && r is IntExpr) {
+      return IntExpr(l.value - r.value);
+    }
+    if (l is FractionExpr && r is FractionExpr) {
+      return FractionExpr(
+        l.numerator * r.denominator - r.numerator * l.denominator,
+        l.denominator * r.denominator,
+      ).simplify();
+    }
+    return SubExpr(l, r);
+  }
+
+  @override
+  Expr evaluate() {
+    var l = left.evaluate();
+    var r = right.evaluate();
+
+    if (l is IntExpr && r is IntExpr) {
+      return IntExpr(l.value - r.value);
+    }
+    if (l is FractionExpr && r is FractionExpr) {
+      return FractionExpr(
+        l.numerator * r.denominator - r.numerator * l.denominator,
+        l.denominator * r.denominator,
+      ).simplify();
+    }
+    if (l is IntExpr && r is FractionExpr) {
+      return FractionExpr(
+        l.value * r.denominator - r.numerator,
+        r.denominator,
+      ).simplify();
+    }
+    if (l is FractionExpr && r is IntExpr) {
+      return FractionExpr(
+        l.numerator - r.value * l.denominator,
+        l.denominator,
+      ).simplify();
+    }
+
+    // 处理同类 sqrt 项: a*sqrt(X) - b*sqrt(X) = (a-b)*sqrt(X)
+    var a = _asSqrtTerm(l);
+    var b = _asSqrtTerm(r);
+    if (a != null && b != null && a.inner.toString() == b.inner.toString()) {
+      return MulExpr(IntExpr(a.coef - b.coef), SqrtExpr(a.inner)).simplify();
+    }
+
+    return SubExpr(l, r);
+  }
+
+  @override
+  String toString() => "($left - $right)";
+}
+
+// === MulExpr.evaluate ===
+class MulExpr extends Expr {
+  final Expr left, right;
+  MulExpr(this.left, this.right);
+
+  @override
+  Expr simplify() {
+    var l = left.simplify();
+    var r = right.simplify();
+
+    if (l is IntExpr && l.value == 1) return r;
+    if (r is IntExpr && r.value == 1) return l;
+    if (l is IntExpr && l.value == -1) return SubExpr(IntExpr(0), r).simplify();
+    if (r is IntExpr && r.value == -1) return SubExpr(IntExpr(0), l).simplify();
+
+    if (l is IntExpr && r is IntExpr) {
+      return IntExpr(l.value * r.value);
+    }
+    if (l is FractionExpr && r is IntExpr) {
+      return FractionExpr(l.numerator * r.value, l.denominator).simplify();
+    }
+    if (l is IntExpr && r is FractionExpr) {
+      return FractionExpr(l.value * r.numerator, r.denominator).simplify();
+    }
+    if (l is FractionExpr && r is FractionExpr) {
+      return FractionExpr(
+        l.numerator * r.numerator,
+        l.denominator * r.denominator,
+      ).simplify();
+    }
+    if (l is SqrtExpr && r is FractionExpr) {
+      return FractionExpr(1, r.denominator).simplify() *
+          MulExpr(l, IntExpr(r.numerator)).simplify();
+    }
+
+    return MulExpr(l, r);
+  }
+
+  @override
+  Expr evaluate() {
+    var l = left.evaluate();
+    var r = right.evaluate();
+
+    if (l is IntExpr && l.value == 1) return r;
+    if (r is IntExpr && r.value == 1) return l;
+    if (l is IntExpr && l.value == -1) return SubExpr(IntExpr(0), r).simplify();
+    if (r is IntExpr && r.value == -1) return SubExpr(IntExpr(0), l).simplify();
+
+    if (l is IntExpr && r is IntExpr) {
+      return IntExpr(l.value * r.value);
+    }
+    if (l is FractionExpr && r is IntExpr) {
+      return FractionExpr(l.numerator * r.value, l.denominator).simplify();
+    }
+    if (l is IntExpr && r is FractionExpr) {
+      return FractionExpr(l.value * r.numerator, r.denominator).simplify();
+    }
+    if (l is FractionExpr && r is FractionExpr) {
+      return FractionExpr(
+        l.numerator * r.numerator,
+        l.denominator * r.denominator,
+      ).simplify();
+    }
+
+    // sqrt * sqrt: sqrt(a)*sqrt(a) = a
+    if (l is SqrtExpr &&
+        r is SqrtExpr &&
+        l.inner.toString() == r.inner.toString()) {
+      return l.inner.simplify();
+    }
+
+    // int * sqrt -> 保留形式，之后 simplify() 再处理约分
+    if ((l is IntExpr && r is SqrtExpr) || (l is SqrtExpr && r is IntExpr)) {
+      return MulExpr(l, r).simplify();
+    }
+
+    return MulExpr(l, r);
+  }
+
+  @override
+  String toString() => "($left * $right)";
+}
+
+// === DivExpr.evaluate ===
+class DivExpr extends Expr {
+  final Expr left, right;
+  DivExpr(this.left, this.right);
+
+  @override
+  Expr simplify() {
+    var l = left.simplify();
+    var r = right.simplify();
+
+    if (l is IntExpr && r is IntExpr) {
+      return FractionExpr(l.value, r.value).simplify();
+    }
+    if (l is FractionExpr && r is IntExpr) {
+      return FractionExpr(l.numerator, l.denominator * r.value).simplify();
+    }
+    if (l is IntExpr && r is FractionExpr) {
+      return FractionExpr(l.value * r.denominator, r.numerator).simplify();
+    }
+    if (l is FractionExpr && r is FractionExpr) {
+      return FractionExpr(
+        l.numerator * r.denominator,
+        l.denominator * r.numerator,
+      ).simplify();
+    }
+    if (l is MulExpr &&
+        l.left is IntExpr &&
+        l.right is SqrtExpr &&
+        r is IntExpr) {
+      int coeff = (l.left as IntExpr).value;
+      int denom = r.value;
+      int g = _gcd(coeff.abs(), denom.abs());
+      return MulExpr(
+        IntExpr(coeff ~/ g),
+        DivExpr(l.right, IntExpr(denom ~/ g)).simplify(),
+      ).simplify();
+    }
+    return DivExpr(l, r);
+  }
+
+  @override
+  Expr evaluate() {
+    var l = left.evaluate();
+    var r = right.evaluate();
+
+    if (l is IntExpr && r is IntExpr) {
+      return FractionExpr(l.value, r.value).simplify();
+    }
+    if (l is FractionExpr && r is IntExpr) {
+      return FractionExpr(l.numerator, l.denominator * r.value).simplify();
+    }
+    if (l is IntExpr && r is FractionExpr) {
+      return FractionExpr(l.value * r.denominator, r.numerator).simplify();
+    }
+    if (l is FractionExpr && r is FractionExpr) {
+      return FractionExpr(
+        l.numerator * r.denominator,
+        l.denominator * r.numerator,
+      ).simplify();
+    }
+
+    // handle (k * sqrt(X)) / d 约分
+    if (l is MulExpr &&
+        l.left is IntExpr &&
+        l.right is SqrtExpr &&
+        r is IntExpr) {
+      int coeff = (l.left as IntExpr).value;
+      int denom = r.value;
+      int g = _gcd(coeff.abs(), denom.abs());
+      return MulExpr(
+        IntExpr(coeff ~/ g),
+        DivExpr(l.right, IntExpr(denom ~/ g)).evaluate(),
+      ).evaluate();
+    }
+
+    return DivExpr(l, r);
+  }
+
+  @override
+  String toString() => "($left / $right)";
+}
+
+// === SqrtExpr.evaluate ===
+class SqrtExpr extends Expr {
+  final Expr inner;
+  SqrtExpr(this.inner);
+
+  @override
+  Expr simplify() {
+    var i = inner.simplify();
+    if (i is IntExpr) {
+      int n = i.value;
+      int root = sqrt(n).floor();
+      if (root * root == n) {
+        return IntExpr(root); // 完全平方数
+      }
+      // 尝试拆分 sqrt，比如 sqrt(8) = 2*sqrt(2)
+      for (int k = root; k > 1; k--) {
+        if (n % (k * k) == 0) {
+          return MulExpr(
+            IntExpr(k),
+            SqrtExpr(IntExpr(n ~/ (k * k))),
+          ).simplify();
+        }
+      }
+    }
+    return SqrtExpr(i);
+  }
+
+  @override
+  Expr evaluate() {
+    var i = inner.evaluate();
+    if (i is IntExpr) {
+      int n = i.value;
+      int root = sqrt(n).floor();
+      if (root * root == n) return IntExpr(root);
+      // 拆平方因子并返回 k * sqrt(remain)
+      for (int k = root; k > 1; k--) {
+        if (n % (k * k) == 0) {
+          return MulExpr(
+            IntExpr(k),
+            SqrtExpr(IntExpr(n ~/ (k * k))),
+          ).evaluate();
+        }
+      }
+    }
+    return SqrtExpr(i);
+  }
+
+  @override
+  String toString() => "sqrt($inner)";
+}
+
+// === CosExpr ===
+class CosExpr extends Expr {
+  final Expr inner;
+  CosExpr(this.inner);
+
+  @override
+  Expr simplify() => CosExpr(inner.simplify());
+
+  @override
+  Expr evaluate() {
+    var i = inner.evaluate();
+    if (i is IntExpr) {
+      return DoubleExpr(cos(i.value.toDouble()));
+    }
+    if (i is FractionExpr) {
+      return DoubleExpr(cos(i.numerator / i.denominator));
+    }
+    if (i is DoubleExpr) {
+      return DoubleExpr(cos(i.value));
+    }
+    return CosExpr(i);
+  }
+
+  @override
+  String toString() => "cos($inner)";
+}
+
+// === SinExpr ===
+class SinExpr extends Expr {
+  final Expr inner;
+  SinExpr(this.inner);
+
+  @override
+  Expr simplify() => SinExpr(inner.simplify());
+
+  @override
+  Expr evaluate() {
+    var i = inner.evaluate();
+    if (i is IntExpr) {
+      return DoubleExpr(sin(i.value.toDouble()));
+    }
+    if (i is FractionExpr) {
+      return DoubleExpr(sin(i.numerator / i.denominator));
+    }
+    if (i is DoubleExpr) {
+      return DoubleExpr(sin(i.value));
+    }
+    return SinExpr(i);
+  }
+
+  @override
+  String toString() => "sin($inner)";
+}
+
+// === TanExpr ===
+class TanExpr extends Expr {
+  final Expr inner;
+  TanExpr(this.inner);
+
+  @override
+  Expr simplify() => TanExpr(inner.simplify());
+
+  @override
+  Expr evaluate() {
+    var i = inner.evaluate();
+    if (i is IntExpr) {
+      return DoubleExpr(tan(i.value.toDouble()));
+    }
+    if (i is FractionExpr) {
+      return DoubleExpr(tan(i.numerator / i.denominator));
+    }
+    if (i is DoubleExpr) {
+      return DoubleExpr(tan(i.value));
+    }
+    return TanExpr(i);
+  }
+
+  @override
+  String toString() => "tan($inner)";
+}
+
+// === 辅助：识别 a * sqrt(X) 形式 ===
+class _SqrtTerm {
+  final int coef;
+  final Expr inner;
+  _SqrtTerm(this.coef, this.inner);
+}
+
+_SqrtTerm? _asSqrtTerm(Expr e) {
+  if (e is SqrtExpr) return _SqrtTerm(1, e.inner);
+  if (e is MulExpr) {
+    // 可能为 Int * Sqrt or Sqrt * Int
+    if (e.left is IntExpr && e.right is SqrtExpr) {
+      return _SqrtTerm((e.left as IntExpr).value, (e.right as SqrtExpr).inner);
+    }
+    if (e.right is IntExpr && e.left is SqrtExpr) {
+      return _SqrtTerm((e.right as IntExpr).value, (e.left as SqrtExpr).inner);
+    }
+  }
+  return null;
+}
+
+/// 辗转相除法求 gcd
+int _gcd(int a, int b) => b == 0 ? a : _gcd(b, a % b);

lib/parser.dart

@@ -0,0 +1,111 @@
+import 'package:simple_math_calc/calculator.dart';
+
+class Parser {
+  final String input;
+  int pos = 0;
+
+  Parser(this.input);
+
+  bool get isEnd => pos >= input.length;
+  String get current => isEnd ? '' : input[pos];
+
+  void eat() => pos++;
+
+  void skipSpaces() {
+    while (!isEnd && input[pos] == ' ') {
+      eat();
+    }
+  }
+
+  Expr parse() => parseAdd();
+
+  Expr parseAdd() {
+    var expr = parseMul();
+    skipSpaces();
+    while (!isEnd && (current == '+' || current == '-')) {
+      var op = current;
+      eat();
+      var right = parseMul();
+      expr = op == '+' ? AddExpr(expr, right) : SubExpr(expr, right);
+      skipSpaces();
+    }
+    return expr;
+  }
+
+  Expr parseMul() {
+    var expr = parseAtom();
+    skipSpaces();
+    while (!isEnd && (current == '*' || current == '/')) {
+      var op = current;
+      eat();
+      var right = parseAtom();
+      if (op == '*') {
+        expr = MulExpr(expr, right);
+      } else {
+        expr = DivExpr(expr, right);
+      }
+      skipSpaces();
+    }
+    return expr;
+  }
+
+  Expr parseAtom() {
+    skipSpaces();
+    if (current == '(') {
+      eat();
+      var expr = parse();
+      if (current != ')') throw Exception("缺少 )");
+      eat();
+      return expr;
+    }
+
+    if (input.startsWith("sqrt", pos)) {
+      pos += 4;
+      if (current != '(') throw Exception("sqrt 缺少 (");
+      eat();
+      var inner = parse();
+      if (current != ')') throw Exception("sqrt 缺少 )");
+      eat();
+      return SqrtExpr(inner);
+    }
+
+    if (input.startsWith("cos", pos)) {
+      pos += 3;
+      if (current != '(') throw Exception("cos 缺少 (");
+      eat();
+      var inner = parse();
+      if (current != ')') throw Exception("cos 缺少 )");
+      eat();
+      return CosExpr(inner);
+    }
+
+    if (input.startsWith("sin", pos)) {
+      pos += 3;
+      if (current != '(') throw Exception("sin 缺少 (");
+      eat();
+      var inner = parse();
+      if (current != ')') throw Exception("sin 缺少 )");
+      eat();
+      return SinExpr(inner);
+    }
+
+    if (input.startsWith("tan", pos)) {
+      pos += 3;
+      if (current != '(') throw Exception("tan 缺少 (");
+      eat();
+      var inner = parse();
+      if (current != ')') throw Exception("tan 缺少 )");
+      eat();
+      return TanExpr(inner);
+    }
+
+    // 解析整数
+    var buf = '';
+    while (!isEnd && RegExp(r'\d').hasMatch(current)) {
+      buf += current;
+      eat();
+    }
+    if (buf.isEmpty) throw Exception("无法解析: $current");
+    return IntExpr(int.parse(buf));
+  }
+}

lib/solver.dart

@@ -1,8 +1,8 @@
 import 'dart:math';
-import 'package:flutter/foundation.dart'; // For kDebugMode
-import 'package:math_expressions/math_expressions.dart';
 import 'package:rational/rational.dart';
 import 'models/calculation_step.dart';
+import 'calculator.dart';
+import 'parser.dart';
 
 /// 帮助解析一元一次方程 ax+b=cx+d 的辅助类
 class LinearEquationParts {
@@ -43,9 +43,6 @@ class SolverService {
     try {
       return _solveSimpleExpression(input); // 使用原始输入以保留运算符
     } catch (e) {
-      if (kDebugMode) {
-        print(e);
-      }
       throw Exception('无法识别的格式。请检查您的方程或表达式。');
     }
   }
@@ -76,9 +73,30 @@ class SolverService {
     // 预处理输入，将三角函数的参数从度转换为弧度
     String processedInput = _convertTrigToRadians(input);
 
-    GrammarParser p = GrammarParser();
-    Expression exp = p.parse(processedInput);
-    final result = RealEvaluator().evaluate(exp).toDouble();
+    try {
+      // 使用自定义解析器解析表达式
+      final parser = Parser(processedInput);
+      final expr = parser.parse();
+
+      // 对表达式进行求值
+      final evaluatedExpr = expr.evaluate();
+
+      // 获取数值结果 - 需要正确进行类型转换
+      double result;
+      if (evaluatedExpr is IntExpr) {
+        result = evaluatedExpr.value.toDouble();
+      } else if (evaluatedExpr is DoubleExpr) {
+        result = evaluatedExpr.value;
+      } else if (evaluatedExpr is FractionExpr) {
+        result = evaluatedExpr.numerator / evaluatedExpr.denominator;
+      } else {
+        // 如果无法完全求值为数值，尝试简化并转换为字符串
+        final simplified = evaluatedExpr.simplify();
+        return CalculationResult(
+          steps: steps,
+          finalAnswer: '\$\$${simplified.toString()}\$\$',
+        );
+      }
 
       // 尝试将结果格式化为几倍根号的形式
       final formattedResult = _formatSqrtResult(result);
@@ -87,6 +105,9 @@ class SolverService {
         steps: steps,
         finalAnswer: '\$\$$formattedResult\$\$',
       );
+    } catch (e) {
+      throw Exception('无法解析表达式: $input');
+    }
   }
 
   /// 2. 求解一元一次方程
@@ -714,21 +735,28 @@ ${b1}y &= ${c1 - a1 * x.toDouble()}
       if (factorMulMatch != null) {
         final factor1 = factorMulMatch.group(1)!;
         final factor2 = factorMulMatch.group(2)!;
+        print('Expanding: ($factor1) * ($factor2)');
+
         final coeffs1 = _parsePolynomial(factor1);
         final coeffs2 = _parsePolynomial(factor2);
+        print('Coeffs1: $coeffs1, Coeffs2: $coeffs2');
 
         final a = coeffs1[1] ?? 0;
         final b = coeffs1[0] ?? 0;
         final c = coeffs2[1] ?? 0;
         final d = coeffs2[0] ?? 0;
+        print('a=$a, b=$b, c=$c, d=$d');
 
         final newA = a * c;
         final newB = a * d + b * c;
         final newC = b * d;
+        print('newA=$newA, newB=$newB, newC=$newC');
 
         final expanded =
             '${newA}x^2${newB >= 0 ? '+' : ''}${newB}x${newC >= 0 ? '+' : ''}$newC';
-        result = result.replaceFirst(factorMulMatch.group(0)!, '($expanded)');
+        print('Expanded result: $expanded');
+
+        result = result.replaceFirst(factorMulMatch.group(0)!, expanded);
         iterationCount++;
         continue;
       }
@@ -762,7 +790,11 @@ ${b1}y &= ${c1 - a1 * x.toDouble()}
         final newC = termB * factorB;
 
         final expanded =
-            '${newA}x^2${newB >= 0 ? '+' : ''}${newB}x${newC >= 0 ? '+' : ''}$newC';
+            '${newA == 1
+                ? ''
+                : newA == -1
+                ? '-'
+                : newA}x^2${newB >= 0 ? '+' : ''}${newB}x${newC >= 0 ? '+' : ''}$newC';
         result = result.replaceFirst(termFactorMatch.group(0)!, '($expanded)');
         iterationCount++;
         continue;
@@ -776,6 +808,54 @@ ${b1}y &= ${c1 - a1 * x.toDouble()}
       throw Exception('表达式展开过于复杂，请简化输入。');
     }
 
+    // 检查是否为方程（包含等号），如果是的话，将右边的常数项移到左边
+    if (result.contains('=')) {
+      final parts = result.split('=');
+      if (parts.length == 2) {
+        final leftSide = parts[0];
+        final rightSide = parts[1];
+
+        // 解析左边的多项式
+        final leftCoeffs = _parsePolynomial(leftSide);
+        final rightCoeffs = _parsePolynomial(rightSide);
+
+        // 计算标准形式 ax^2 + bx + c = 0 的系数
+        // A = B 转换为 A - B = 0，所以右边的系数要取相反数
+        final a = (leftCoeffs[2] ?? 0) - (rightCoeffs[2] ?? 0);
+        final b = (leftCoeffs[1] ?? 0) - (rightCoeffs[1] ?? 0);
+        final c = (leftCoeffs[0] ?? 0) - (rightCoeffs[0] ?? 0);
+
+        // 构建标准形式的方程
+        String standardForm = '';
+        if (a != 0) {
+          standardForm +=
+              '${a == 1
+                  ? ''
+                  : a == -1
+                  ? '-'
+                  : a}x^2';
+        }
+        if (b != 0) {
+          standardForm += b > 0 ? '+${b}x' : '${b}x';
+        }
+        if (c != 0) {
+          standardForm += c > 0 ? '+$c' : '$c';
+        }
+
+        // 移除开头的加号
+        if (standardForm.startsWith('+')) {
+          standardForm = standardForm.substring(1);
+        }
+
+        // 如果所有系数都为0，则方程恒成立
+        if (standardForm.isEmpty) {
+          standardForm = '0';
+        }
+
+        result = '$standardForm=0';
+      }
+    }
+
     return result;
   }
 
@@ -796,13 +876,24 @@ ${b1}y &= ${c1 - a1 * x.toDouble()}
 
   Map<int, double> _parsePolynomial(String side) {
     final coeffs = <int, double>{};
+
+    // 如果输入包含括号，去掉括号
+    var cleanSide = side;
+    if (cleanSide.startsWith('(') && cleanSide.endsWith(')')) {
+      cleanSide = cleanSide.substring(1, cleanSide.length - 1);
+    }
+
     // 扩展模式以支持 sqrt 函数
     final pattern = RegExp(
       r'([+-]?(?:\d*\.?\d*|sqrt\(\d+\)))x(?:\^(\d+))?|([+-]?(?:\d*\.?\d*|sqrt\(\d+\)))',
     );
-    var s = side.startsWith('+') || side.startsWith('-') ? side : '+$side';
+    var s = cleanSide.startsWith('+') || cleanSide.startsWith('-')
+        ? cleanSide
+        : '+$cleanSide';
 
     for (final match in pattern.allMatches(s)) {
+      if (match.group(0)!.isEmpty) continue; // Skip empty matches
+
       if (match.group(3) != null) {
         // 常数项
         final constStr = match.group(3)!;
@@ -893,26 +984,31 @@ ${b1}y &= ${c1 - a1 * x.toDouble()}
     if (a == 0) return null;
     int ac = a * c;
     int absAc = ac.abs();
+
+    // Try all divisors of abs(ac) and consider both positive and negative factors
     for (int d = 1; d <= sqrt(absAc).toInt(); d++) {
       if (absAc % d == 0) {
         int d1 = d;
         int d2 = absAc ~/ d;
-        List<int> signs1 = ac >= 0 ? [1, -1] : [1, -1];
-        List<int> signs2 = ac >= 0 ? [1, -1] : [1, -1];
-        for (int s1 in signs1) {
-          for (int s2 in signs2) {
-            int m = s1 * d1;
-            int n = s2 * d2;
-            if (check(m, n, b)) return formatFactor(m, n, a);
-            m = s1 * d1;
-            n = s2 * (-d2);
-            if (check(m, n, b)) return formatFactor(m, n, a);
-            m = s1 * (-d1);
-            n = s2 * d2;
-            if (check(m, n, b)) return formatFactor(m, n, a);
-            m = s1 * (-d1);
-            n = s2 * (-d2);
-            if (check(m, n, b)) return formatFactor(m, n, a);
+
+        // Try all sign combinations for the factors
+        // We need m * n = ac and m + n = b
+        List<int> signCombinations = [1, -1];
+
+        for (int sign1 in signCombinations) {
+          for (int sign2 in signCombinations) {
+            int m = sign1 * d1;
+            int n = sign2 * d2;
+            if (m + n == b && m * n == ac) {
+              return formatFactor(m, n, a);
+            }
+
+            // Also try the swapped version
+            m = sign1 * d2;
+            n = sign2 * d1;
+            if (m + n == b && m * n == ac) {
+              return formatFactor(m, n, a);
+            }
           }
         }
       }
@@ -1109,10 +1205,11 @@ ${b1}y &= ${c1 - a1 * x.toDouble()}
     for (int i = 0; i < s.length; i++) {
       final char = s[i];
 
-      if (char == '(')
+      if (char == '(') {
         parenDepth++;
-      else if (char == ')')
+      } else if (char == ')') {
         parenDepth--;
+      }
 
       // Only split on + or - when not inside parentheses
       if (parenDepth == 0 && (char == '+' || char == '-') && i > start) {

pubspec.lock

@@ -1,6 +1,22 @@
 # Generated by pub
 # See https://dart.dev/tools/pub/glossary#lockfile
 packages:
+  _fe_analyzer_shared:
+    dependency: transitive
+    description:
+      name: _fe_analyzer_shared
+      sha256: da0d9209ca76bde579f2da330aeb9df62b6319c834fa7baae052021b0462401f
+      url: "https://pub.dev"
+    source: hosted
+    version: "85.0.0"
+  analyzer:
+    dependency: transitive
+    description:
+      name: analyzer
+      sha256: "974859dc0ff5f37bc4313244b3218c791810d03ab3470a579580279ba971a48d"
+      url: "https://pub.dev"
+    source: hosted
+    version: "7.7.1"
   ansicolor:
     dependency: transitive
     description:
@@ -57,6 +73,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.0.4"
+  cli_config:
+    dependency: transitive
+    description:
+      name: cli_config
+      sha256: ac20a183a07002b700f0c25e61b7ee46b23c309d76ab7b7640a028f18e4d99ec
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.2.0"
   cli_util:
     dependency: transitive
     description:
@@ -81,6 +105,22 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.19.1"
+  convert:
+    dependency: transitive
+    description:
+      name: convert
+      sha256: b30acd5944035672bc15c6b7a8b47d773e41e2f17de064350988c5d02adb1c68
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.1.2"
+  coverage:
+    dependency: transitive
+    description:
+      name: coverage
+      sha256: "5da775aa218eaf2151c721b16c01c7676fbfdd99cebba2bf64e8b807a28ff94d"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.15.0"
   crypto:
     dependency: transitive
     description:
@@ -121,6 +161,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.1.4"
+  file:
+    dependency: transitive
+    description:
+      name: file
+      sha256: a3b4f84adafef897088c160faf7dfffb7696046cb13ae90b508c2cbc95d3b8d4
+      url: "https://pub.dev"
+    source: hosted
+    version: "7.0.1"
   flutter:
     dependency: "direct main"
     description: flutter
@@ -176,14 +224,30 @@ packages:
     description: flutter
     source: sdk
     version: "0.0.0"
+  frontend_server_client:
+    dependency: transitive
+    description:
+      name: frontend_server_client
+      sha256: f64a0333a82f30b0cca061bc3d143813a486dc086b574bfb233b7c1372427694
+      url: "https://pub.dev"
+    source: hosted
+    version: "4.0.0"
+  glob:
+    dependency: transitive
+    description:
+      name: glob
+      sha256: c3f1ee72c96f8f78935e18aa8cecced9ab132419e8625dc187e1c2408efc20de
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.1.3"
   go_router:
     dependency: "direct main"
     description:
       name: go_router
-      sha256: f02fd7d2a4dc512fec615529824fdd217fecb3a3d3de68360293a551f21634b3
+      sha256: eb059dfe59f08546e9787f895bd01652076f996bcbf485a8609ef990419ad227
       url: "https://pub.dev"
     source: hosted
-    version: "14.8.1"
+    version: "16.2.1"
   google_fonts:
     dependency: "direct main"
     description:
@@ -208,6 +272,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.5.0"
+  http_multi_server:
+    dependency: transitive
+    description:
+      name: http_multi_server
+      sha256: aa6199f908078bb1c5efb8d8638d4ae191aac11b311132c3ef48ce352fb52ef8
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.2.2"
   http_parser:
     dependency: transitive
     description:
@@ -224,6 +296,22 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "4.5.4"
+  io:
+    dependency: transitive
+    description:
+      name: io
+      sha256: dfd5a80599cf0165756e3181807ed3e77daf6dd4137caaad72d0b7931597650b
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.0.5"
+  js:
+    dependency: transitive
+    description:
+      name: js
+      sha256: "53385261521cc4a0c4658fd0ad07a7d14591cf8fc33abbceae306ddb974888dc"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.7.2"
   json_annotation:
     dependency: transitive
     description:
@@ -312,6 +400,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.16.0"
+  mime:
+    dependency: transitive
+    description:
+      name: mime
+      sha256: "41a20518f0cb1256669420fdba0cd90d21561e560ac240f26ef8322e45bb7ed6"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.0.0"
   nested:
     dependency: transitive
     description:
@@ -320,6 +416,22 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.0.0"
+  node_preamble:
+    dependency: transitive
+    description:
+      name: node_preamble
+      sha256: "6e7eac89047ab8a8d26cf16127b5ed26de65209847630400f9aefd7cd5c730db"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.0.2"
+  package_config:
+    dependency: transitive
+    description:
+      name: package_config
+      sha256: f096c55ebb7deb7e384101542bfba8c52696c1b56fca2eb62827989ef2353bbc
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.2.0"
   path:
     dependency: transitive
     description:
@@ -408,6 +520,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.1.8"
+  pool:
+    dependency: transitive
+    description:
+      name: pool
+      sha256: "20fe868b6314b322ea036ba325e6fc0711a22948856475e2c2b6306e8ab39c2a"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.5.1"
   posix:
     dependency: transitive
     description:
@@ -424,6 +544,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "6.1.5+1"
+  pub_semver:
+    dependency: transitive
+    description:
+      name: pub_semver
+      sha256: "5bfcf68ca79ef689f8990d1160781b4bad40a3bd5e5218ad4076ddb7f4081585"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.2.0"
   rational:
     dependency: "direct main"
     description:
@@ -432,11 +560,59 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.2.3"
+  shelf:
+    dependency: transitive
+    description:
+      name: shelf
+      sha256: e7dd780a7ffb623c57850b33f43309312fc863fb6aa3d276a754bb299839ef12
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.4.2"
+  shelf_packages_handler:
+    dependency: transitive
+    description:
+      name: shelf_packages_handler
+      sha256: "89f967eca29607c933ba9571d838be31d67f53f6e4ee15147d5dc2934fee1b1e"
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.0.2"
+  shelf_static:
+    dependency: transitive
+    description:
+      name: shelf_static
+      sha256: c87c3875f91262785dade62d135760c2c69cb217ac759485334c5857ad89f6e3
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.1.3"
+  shelf_web_socket:
+    dependency: transitive
+    description:
+      name: shelf_web_socket
+      sha256: "3632775c8e90d6c9712f883e633716432a27758216dfb61bd86a8321c0580925"
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.0.0"
   sky_engine:
     dependency: transitive
     description: flutter
     source: sdk
     version: "0.0.0"
+  source_map_stack_trace:
+    dependency: transitive
+    description:
+      name: source_map_stack_trace
+      sha256: c0713a43e323c3302c2abe2a1cc89aa057a387101ebd280371d6a6c9fa68516b
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.1.2"
+  source_maps:
+    dependency: transitive
+    description:
+      name: source_maps
+      sha256: "190222579a448b03896e0ca6eca5998fa810fda630c1d65e2f78b3f638f54812"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.10.13"
   source_span:
     dependency: transitive
     description:
@@ -477,6 +653,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.2.2"
+  test:
+    dependency: "direct dev"
+    description:
+      name: test
+      sha256: "65e29d831719be0591f7b3b1a32a3cda258ec98c58c7b25f7b84241bc31215bb"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.26.2"
   test_api:
     dependency: transitive
     description:
@@ -485,6 +669,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "0.7.6"
+  test_core:
+    dependency: transitive
+    description:
+      name: test_core
+      sha256: "80bf5a02b60af04b09e14f6fe68b921aad119493e26e490deaca5993fef1b05a"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.6.11"
   tuple:
     dependency: transitive
     description:
@@ -613,6 +805,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "15.0.2"
+  watcher:
+    dependency: transitive
+    description:
+      name: watcher
+      sha256: "5bf046f41320ac97a469d506261797f35254fa61c641741ef32dacda98b7d39c"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.1.3"
   web:
     dependency: transitive
     description:
@@ -621,6 +821,30 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.1.1"
+  web_socket:
+    dependency: transitive
+    description:
+      name: web_socket
+      sha256: "34d64019aa8e36bf9842ac014bb5d2f5586ca73df5e4d9bf5c936975cae6982c"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.0.1"
+  web_socket_channel:
+    dependency: transitive
+    description:
+      name: web_socket_channel
+      sha256: d645757fb0f4773d602444000a8131ff5d48c9e47adfe9772652dd1a4f2d45c8
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.0.3"
+  webkit_inspection_protocol:
+    dependency: transitive
+    description:
+      name: webkit_inspection_protocol
+      sha256: "87d3f2333bb240704cd3f1c6b5b7acd8a10e7f0bc28c28dcf14e782014f4a572"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.2.1"
   xdg_directories:
     dependency: transitive
     description:

pubspec.yaml

@@ -37,8 +37,8 @@ dependencies:
   math_expressions: ^3.1.0
   latext: ^0.5.1
   google_fonts: ^6.3.1
-  go_router: ^14.2.0
-  url_launcher: ^6.3.0
+  go_router: ^16.2.1
+  url_launcher: ^6.3.2
   rational: ^2.2.3
 
 dev_dependencies:
@@ -53,6 +53,7 @@ dev_dependencies:
   flutter_lints: ^6.0.0
   flutter_native_splash: ^2.4.6
   flutter_launcher_icons: ^0.14.4
+  test: ^1.26.2
 
 # For information on the generic Dart part of this file, see the
 # following page: https://dart.dev/tools/pub/pubspec

test/calculator_test.dart

@@ -0,0 +1,104 @@
+import 'package:simple_math_calc/parser.dart';
+import 'package:test/test.dart';
+
+void main() {
+  group('整数', () {
+    test('加法', () {
+      var expr = Parser("2 + 3").parse();
+      expect(expr.evaluate().toString(), "5");
+    });
+
+    test('乘法', () {
+      var expr = Parser("4 * 5").parse();
+      expect(expr.evaluate().toString(), "20");
+    });
+  });
+
+  group('分数', () {
+    test('简单分数', () {
+      var expr = Parser("1/2").parse();
+      expect(expr.evaluate().toString(), "1/2");
+    });
+
+    test('分数加法', () {
+      var expr = Parser("1/2 + 3/4").parse();
+      expect(expr.evaluate().toString().replaceAll(' ', ''), "5/4");
+    });
+
+    test('分数与整数相乘', () {
+      var expr = Parser("2 * 3/4").parse();
+      expect(expr.evaluate().toString(), "3/2");
+    });
+  });
+
+  group('开平方', () {
+    test('完全平方数', () {
+      var expr = Parser("sqrt(9)").parse();
+      expect(expr.evaluate().toString(), "3");
+    });
+
+    test('非完全平方数', () {
+      var expr = Parser("sqrt(8)").parse();
+      expect(expr.simplify().toString().replaceAll(' ', ''), "(2*sqrt(2))");
+    });
+  });
+
+  group('组合表达式', () {
+    test('sqrt + 整数', () {
+      var expr = Parser("2 + sqrt(9)").parse();
+      expect(expr.simplify().toString().replaceAll(' ', ''), "(2+3)");
+    });
+
+    test('分数 + sqrt', () {
+      var expr = Parser("sqrt(8)/4 + 1/2").parse();
+      expect(
+        expr.evaluate().toString().replaceAll(' ', ''),
+        "((sqrt(2)/2)+1/2)",
+      );
+    });
+  });
+
+  group('加减除优先级', () {
+    test('减法', () {
+      var expr = Parser("5 - 2").parse();
+      expect(expr.evaluate().toString(), "3");
+    });
+
+    test('除法', () {
+      var expr = Parser("6 / 3").parse();
+      expect(expr.evaluate().toString(), "2");
+    });
+
+    test('加法和乘法优先级', () {
+      var expr = Parser("1 + 2 * 3").parse();
+      expect(expr.evaluate().toString(), "7");
+    });
+
+    test('加减混合', () {
+      var expr = Parser("10 - 3 + 2").parse();
+      expect(expr.evaluate().toString(), "9");
+    });
+
+    test('括号优先级', () {
+      var expr = Parser("(1 + 2) * 3").parse();
+      expect(expr.evaluate().toString(), "9");
+    });
+  });
+
+  group('三角函数', () {
+    test('cos(0)', () {
+      var expr = Parser("cos(0)").parse();
+      expect(expr.evaluate().toString(), "1.0");
+    });
+
+    test('sin(0)', () {
+      var expr = Parser("sin(0)").parse();
+      expect(expr.evaluate().toString(), "0.0");
+    });
+
+    test('tan(0)', () {
+      var expr = Parser("tan(0)").parse();
+      expect(expr.evaluate().toString(), "0.0");
+    });
+  });
+}

test/core_test.dart

@@ -0,0 +1,62 @@
+import 'package:test/test.dart';
+import 'package:simple_math_calc/calculator.dart';
+import 'package:simple_math_calc/parser.dart';
+
+void main() {
+  group('解析器测试', () {
+    test('简单加法', () {
+      final parser = Parser('2 + 3');
+      final expr = parser.parse();
+      final result = expr.evaluate();
+      expect(result.toString(), '5');
+    });
+
+    test('乘法和加法优先级', () {
+      final parser = Parser('2 + 3 * 4');
+      final expr = parser.parse();
+      final result = expr.evaluate();
+      expect(result.toString(), '14');
+    });
+
+    test('括号优先级', () {
+      final parser = Parser('(2 + 3) * 4');
+      final expr = parser.parse();
+      final result = expr.evaluate();
+      expect(result.toString(), '20');
+    });
+
+    test('除法', () {
+      final parser = Parser('10 / 2');
+      final expr = parser.parse();
+      final result = expr.evaluate();
+      expect(result.toString(), '5');
+    });
+
+    test('平方根', () {
+      final parser = Parser('sqrt(9)');
+      final expr = parser.parse();
+      final result = expr.evaluate();
+      expect(result.toString(), '3');
+    });
+  });
+
+  group('计算器测试', () {
+    test('分数简化', () {
+      final fraction = FractionExpr(4, 8);
+      final simplified = fraction.simplify();
+      expect(simplified.toString(), '1/2');
+    });
+
+    test('分数加法', () {
+      final expr = AddExpr(FractionExpr(1, 2), FractionExpr(1, 4));
+      final result = expr.evaluate();
+      expect(result.toString(), '3/4');
+    });
+
+    test('分数乘法', () {
+      final expr = MulExpr(FractionExpr(1, 2), FractionExpr(2, 3));
+      final result = expr.evaluate();
+      expect(result.toString(), '1/3');
+    });
+  });
+}

test/solver_test.dart

@@ -0,0 +1,58 @@
+import 'package:flutter/widgets.dart';
+import 'package:test/test.dart';
+import 'package:simple_math_calc/solver.dart';
+
+void main() {
+  group('求解器测试', () {
+    final solver = SolverService();
+
+    test('简单表达式求值', () {
+      final result = solver.solve('2 + 3 * 4');
+      expect(result.finalAnswer, contains('14'));
+    });
+
+    test('简单方程求解', () {
+      final result = solver.solve('2x + 3 = 7');
+      expect(result.finalAnswer, contains('x = 2'));
+    });
+
+    test('二次方程求解', () {
+      final result = solver.solve('x^2 - 5x + 6 = 0');
+      debugPrint(result.finalAnswer);
+      expect(
+        result.finalAnswer.contains('x_1 = 2') &&
+            result.finalAnswer.contains('x_2 = 3'),
+        true,
+      );
+    });
+
+    test('三角函数求值', () {
+      final result = solver.solve('sin(30)');
+      debugPrint(result.finalAnswer);
+      expect(result.finalAnswer.contains(r'\frac{1}{2}'), true);
+    });
+
+    test('带括号的复杂表达式', () {
+      final result = solver.solve('(2 + 3) * 4');
+      expect(result.finalAnswer, contains('20'));
+    });
+
+    test('括号展开的二次方程', () {
+      final result = solver.solve('(x+8)(x+1)=-12');
+      debugPrint('Result for (x+8)(x+1)=-12: ${result.finalAnswer}');
+      // 这个方程应该被识别为一元二次方程，正确解应该是 x = -4 或 x = -5
+      expect(
+        result.steps.any((step) => step.title == '整理方程'),
+        true,
+        reason: '方程应被识别为一元二次方程并进行整理',
+      );
+      expect(
+        (result.finalAnswer.contains('-4') &&
+                result.finalAnswer.contains('-5')) ||
+            result.finalAnswer.contains('x = -4') ||
+            result.finalAnswer.contains('x = -5'),
+        true,
+      );
+    });
+  });
+}

test_expand.dart

@@ -0,0 +1,21 @@
+import 'lib/solver.dart';
+
+void main() {
+  final solver = SolverService();
+
+  // Test the problematic case
+  final input = '(x+8)(x+1)=-12';
+  print('Input: $input');
+
+  try {
+    final result = solver.solve(input);
+    print('Result: ${result.finalAnswer}');
+    print('Steps:');
+    for (final step in result.steps) {
+      print('Step ${step.stepNumber}: ${step.title}');
+      print('  Formula: ${step.formula}');
+    }
+  } catch (e) {
+    print('Error: $e');
+  }
+}