feat: add VariableRefs tracking on Motion and Feedrate

Adds Dictionary<string,string> VariableRefs to Motion (cleared on Rotate/Offset) and string VariableRef to Feedrate, with deep-copy Clone() support, so post processors can emit variable references instead of literal coordinate values.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

OpenNest.Core/CNC/ArcMove.cs

@@ -1,4 +1,5 @@
-using OpenNest.Geometry;
+using System.Collections.Generic;
+using OpenNest.Geometry;
 
 namespace OpenNest.CNC
 {
@@ -66,7 +67,8 @@ namespace OpenNest.CNC
             return new ArcMove(EndPoint, CenterPoint, Rotation)
             {
                 Layer = Layer,
-                Suppressed = Suppressed
+                Suppressed = Suppressed,
+                VariableRefs = VariableRefs != null ? new Dictionary<string, string>(VariableRefs) : null
             };
         }
 

OpenNest.Core/CNC/Feedrate.cs

@@ -17,6 +17,8 @@
 
         public double Value { get; set; }
 
+        public string VariableRef { get; set; }
+
         public CodeType Type
         {
             get { return CodeType.SetFeedrate; }
@@ -24,7 +26,7 @@
 
         public ICode Clone()
         {
-            return new Feedrate(Value);
+            return new Feedrate(Value) { VariableRef = VariableRef };
         }
 
         public override string ToString()

OpenNest.Core/CNC/LinearMove.cs

@@ -1,4 +1,5 @@
-using OpenNest.Geometry;
+using System.Collections.Generic;
+using OpenNest.Geometry;
 
 namespace OpenNest.CNC
 {
@@ -32,7 +33,8 @@ namespace OpenNest.CNC
             return new LinearMove(EndPoint)
             {
                 Layer = Layer,
-                Suppressed = Suppressed
+                Suppressed = Suppressed,
+                VariableRefs = VariableRefs != null ? new Dictionary<string, string>(VariableRefs) : null
             };
         }
 

OpenNest.Core/CNC/Motion.cs

@@ -1,4 +1,5 @@
-using OpenNest.Geometry;
+using System.Collections.Generic;
+using OpenNest.Geometry;
 
 namespace OpenNest.CNC
 {
@@ -14,6 +15,8 @@ namespace OpenNest.CNC
 
         public bool Suppressed { get; set; }
 
+        public Dictionary<string, string> VariableRefs { get; set; }
+
         protected Motion()
         {
             Feedrate = CNC.Feedrate.UseDefault;
@@ -22,21 +25,25 @@ namespace OpenNest.CNC
         public virtual void Rotate(double angle)
         {
             EndPoint = EndPoint.Rotate(angle);
+            VariableRefs = null;
         }
 
         public virtual void Rotate(double angle, Vector origin)
         {
             EndPoint = EndPoint.Rotate(angle, origin);
+            VariableRefs = null;
         }
 
         public virtual void Offset(double x, double y)
         {
             EndPoint = new Vector(EndPoint.X + x, EndPoint.Y + y);
+            VariableRefs = null;
         }
 
         public virtual void Offset(Vector voffset)
         {
             EndPoint += voffset;
+            VariableRefs = null;
         }
 
         public abstract CodeType Type { get; }

OpenNest.Core/CNC/RapidMove.cs

@@ -1,4 +1,5 @@
-using OpenNest.Geometry;
+using System.Collections.Generic;
+using OpenNest.Geometry;
 
 namespace OpenNest.CNC
 {
@@ -28,7 +29,8 @@ namespace OpenNest.CNC
         {
             return new RapidMove(EndPoint)
             {
-                Suppressed = Suppressed
+                Suppressed = Suppressed,
+                VariableRefs = VariableRefs != null ? new Dictionary<string, string>(VariableRefs) : null
             };
         }
 

OpenNest.Tests/CNC/ProgramVariableTests.cs

@@ -0,0 +1,104 @@
+using System.Collections.Generic;
+using OpenNest.CNC;
+using OpenNest.Geometry;
+
+namespace OpenNest.Tests.CNC;
+
+public class ProgramVariableTests
+{
+    [Fact]
+    public void LinearMove_VariableRefs_NullByDefault()
+    {
+        var move = new LinearMove(1.0, 2.0);
+        Assert.Null(move.VariableRefs);
+    }
+
+    [Fact]
+    public void LinearMove_Clone_CopiesVariableRefs()
+    {
+        var move = new LinearMove(1.0, 2.0);
+        move.VariableRefs = new Dictionary<string, string> { { "X", "width" } };
+        var clone = (LinearMove)move.Clone();
+        Assert.NotSame(move.VariableRefs, clone.VariableRefs);
+        Assert.Equal("width", clone.VariableRefs["X"]);
+    }
+
+    [Fact]
+    public void LinearMove_Clone_NullRefs_StaysNull()
+    {
+        var move = new LinearMove(1.0, 2.0);
+        var clone = (LinearMove)move.Clone();
+        Assert.Null(clone.VariableRefs);
+    }
+
+    [Fact]
+    public void ArcMove_Clone_CopiesVariableRefs()
+    {
+        var move = new ArcMove(1, 0, 0.5, 0);
+        move.VariableRefs = new Dictionary<string, string> { { "I", "radius" } };
+        var clone = (ArcMove)move.Clone();
+        Assert.NotSame(move.VariableRefs, clone.VariableRefs);
+        Assert.Equal("radius", clone.VariableRefs["I"]);
+    }
+
+    [Fact]
+    public void RapidMove_Clone_CopiesVariableRefs()
+    {
+        var move = new RapidMove(5.0, 0);
+        move.VariableRefs = new Dictionary<string, string> { { "X", "start_x" } };
+        var clone = (RapidMove)move.Clone();
+        Assert.NotSame(move.VariableRefs, clone.VariableRefs);
+        Assert.Equal("start_x", clone.VariableRefs["X"]);
+    }
+
+    [Fact]
+    public void Feedrate_VariableRef_NullByDefault()
+    {
+        var f = new Feedrate(100.0);
+        Assert.Null(f.VariableRef);
+    }
+
+    [Fact]
+    public void Feedrate_Clone_CopiesVariableRef()
+    {
+        var f = new Feedrate(100.0) { VariableRef = "cut_speed" };
+        var clone = (Feedrate)f.Clone();
+        Assert.Equal("cut_speed", clone.VariableRef);
+    }
+
+    [Fact]
+    public void Motion_Rotate_ClearsVariableRefs()
+    {
+        var move = new LinearMove(1.0, 0);
+        move.VariableRefs = new Dictionary<string, string> { { "X", "width" } };
+        move.Rotate(System.Math.PI / 2);
+        Assert.Null(move.VariableRefs);
+    }
+
+    [Fact]
+    public void Motion_Offset_ClearsVariableRefs()
+    {
+        var move = new LinearMove(1.0, 0);
+        move.VariableRefs = new Dictionary<string, string> { { "X", "width" } };
+        move.Offset(5.0, 0);
+        Assert.Null(move.VariableRefs);
+    }
+
+    [Fact]
+    public void ArcMove_Rotate_ClearsVariableRefs()
+    {
+        var move = new ArcMove(1, 0, 0.5, 0);
+        move.VariableRefs = new Dictionary<string, string> { { "I", "radius" } };
+        move.Rotate(System.Math.PI / 2);
+        Assert.Null(move.VariableRefs);
+    }
+
+    [Fact]
+    public void ArcMove_Offset_ClearsVariableRefs()
+    {
+        var move = new ArcMove(1, 0, 0.5, 0);
+        move.VariableRefs = new Dictionary<string, string> { { "I", "radius" } };
+        move.Offset(5.0, 0);
+        Assert.Null(move.VariableRefs);
+    }
+}