chore: initial git load of code space

src/Strata.SqlTools.Rules/Rule/Expression/Comparison.cs

@@ -0,0 +1,64 @@
+using System.Diagnostics;
+
+namespace Strata.SqlTools.Rules.Rule.Expression;
+
+/// <summary>
+/// Represents a comparison operation between two expressions.
+/// </summary>
+[DebuggerDisplay("{Left} {Type} {Right}")]
+public abstract class Comparison : BoolExpr, IBinary
+{
+    /// <summary>
+    /// Gets the left operand of the comparison.
+    /// </summary>
+    public Expression Left { get; }
+
+    /// <summary>
+    /// Gets the right operand of the comparison.
+    /// </summary>
+    public Expression Right { get; }
+
+    /// <summary>
+    /// Gets the type of comparison operation.
+    /// </summary>
+    public abstract Type Type { get; }
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="Comparison"/> class.
+    /// </summary>
+    /// <param name="left">The left operand.</param>
+    /// <param name="right">The right operand.</param>
+    protected Comparison(Expression left, Expression right)
+    {
+        Left = left;
+        Right = right;
+    }
+
+    /// <summary>
+    /// Creates a new comparison expression with updated operands.
+    /// </summary>
+    /// <param name="left">The new left operand.</param>
+    /// <param name="right">The new right operand.</param>
+    /// <returns>A new comparison expression or this instance if operands are unchanged.</returns>
+    public Expression Update(Expression left, Expression right)
+    {
+        if (ReferenceEquals(left, Left) && ReferenceEquals(right, Right))
+        {
+            return this;
+        }
+
+        return Create(left, right, Type);
+    }
+
+    private static Comparison Create(Expression left, Expression right, Type Type)
+    {
+        return Type switch
+        {
+            Type.Equal => new Equal(left, right),
+            Type.NotEqual => new NotEqual(left, right),
+            Type.GreaterThan => new GreaterThan(left, right),
+
+            _ => throw new NotImplementedException("not yet")
+        };
+    }
+}