up

src/Policy/StellaOps.PolicyDsl/SourceLocation.cs

@@ -0,0 +1,97 @@
+using System.Diagnostics.CodeAnalysis;
+
+namespace StellaOps.PolicyDsl;
+
+/// <summary>
+/// Represents a precise source location within a policy DSL document.
+/// </summary>
+public readonly struct SourceLocation : IEquatable<SourceLocation>, IComparable<SourceLocation>
+{
+    public SourceLocation(int offset, int line, int column)
+    {
+        if (offset < 0)
+        {
+            throw new ArgumentOutOfRangeException(nameof(offset));
+        }
+
+        if (line < 1)
+        {
+            throw new ArgumentOutOfRangeException(nameof(line));
+        }
+
+        if (column < 1)
+        {
+            throw new ArgumentOutOfRangeException(nameof(column));
+        }
+
+        Offset = offset;
+        Line = line;
+        Column = column;
+    }
+
+    public int Offset { get; }
+
+    public int Line { get; }
+
+    public int Column { get; }
+
+    public override string ToString() => $"(L{Line}, C{Column})";
+
+    public bool Equals(SourceLocation other) =>
+        Offset == other.Offset && Line == other.Line && Column == other.Column;
+
+    public override bool Equals([NotNullWhen(true)] object? obj) =>
+        obj is SourceLocation other && Equals(other);
+
+    public override int GetHashCode() => HashCode.Combine(Offset, Line, Column);
+
+    public int CompareTo(SourceLocation other) => Offset.CompareTo(other.Offset);
+
+    public static bool operator ==(SourceLocation left, SourceLocation right) => left.Equals(right);
+
+    public static bool operator !=(SourceLocation left, SourceLocation right) => !left.Equals(right);
+
+    public static bool operator <(SourceLocation left, SourceLocation right) => left.CompareTo(right) < 0;
+
+    public static bool operator <=(SourceLocation left, SourceLocation right) => left.CompareTo(right) <= 0;
+
+    public static bool operator >(SourceLocation left, SourceLocation right) => left.CompareTo(right) > 0;
+
+    public static bool operator >=(SourceLocation left, SourceLocation right) => left.CompareTo(right) >= 0;
+}
+
+/// <summary>
+/// Represents a start/end location pair within a policy DSL source document.
+/// </summary>
+public readonly struct SourceSpan : IEquatable<SourceSpan>
+{
+    public SourceSpan(SourceLocation start, SourceLocation end)
+    {
+        if (start.Offset > end.Offset)
+        {
+            throw new ArgumentException("Start must not be after end.", nameof(start));
+        }
+
+        Start = start;
+        End = end;
+    }
+
+    public SourceLocation Start { get; }
+
+    public SourceLocation End { get; }
+
+    public override string ToString() => $"{Start}->{End}";
+
+    public bool Equals(SourceSpan other) => Start.Equals(other.Start) && End.Equals(other.End);
+
+    public override bool Equals([NotNullWhen(true)] object? obj) => obj is SourceSpan other && Equals(other);
+
+    public override int GetHashCode() => HashCode.Combine(Start, End);
+
+    public static SourceSpan Combine(SourceSpan first, SourceSpan second)
+    {
+        var start = first.Start <= second.Start ? first.Start : second.Start;
+        var end = first.End >= second.End ? first.End : second.End;
+        return new SourceSpan(start, end);
+    }
+}