Made a number of fields ReadOnly that are never mutated

OSCADSharp/OSCADSharp/DataBinding/BindableBoolean.cs

@@ -31,7 +31,7 @@ namespace OSCADSharp.DataBinding
             this.bindings.Synonym("innervalue", propertyName);
         }
 
-        private string boundProperty = null;
+        private readonly string boundProperty = null;
 
         internal bool IsBound { get; set; } = false;
         public void Bind(string property, Variable variable)

OSCADSharp/OSCADSharp/DataBinding/Bindings.cs

@@ -11,7 +11,7 @@ namespace OSCADSharp.DataBinding
     {
         #region Fields
         private Dictionary<string, Binding> bindings = new Dictionary<string, Binding>();
-        private Dictionary<string, string> propertyNametoOpenSCADFieldMappings = new Dictionary<string, string>();
+        private readonly Dictionary<string, string> propertyNametoOpenSCADFieldMappings = new Dictionary<string, string>();
         private Dictionary<string, string> synonyms = new Dictionary<string, string>();
         #endregion
 

OSCADSharp/OSCADSharp/DataBinding/Variables.cs

@@ -17,7 +17,7 @@ namespace OSCADSharp.DataBinding
         /// top of OpenSCAD scripts
         /// </summary>
         public static Variables Global { get; set; } = new Variables();
-        private ConcurrentDictionary<string, Variable> variables = new ConcurrentDictionary<string, Variable>();
+        private readonly ConcurrentDictionary<string, Variable> variables = new ConcurrentDictionary<string, Variable>();
 
         /// <summary>
         /// Adds a variable to the collection

OSCADSharp/OSCADSharp/IO/OutputSettings.cs

@@ -31,7 +31,7 @@ namespace OSCADSharp.IO
         /// </summary>
         private class OpenSCADPathFinder
         {
-            private string[] possibleFilePaths = new string[]
+            private readonly string[] possibleFilePaths = new string[]
             {
             @"C:\Program Files (x86)\OpenSCAD\openscad.exe",
             @"C:\Program Files\OpenSCAD\openscad.exe"

OSCADSharp/OSCADSharp/OSCADObject.AbstractTransforms.cs

@@ -15,7 +15,7 @@ namespace OSCADSharp
         /// <summary>
         /// An object that's mirrored on a plane
         /// </summary>
-        internal class MirroredObject : SingleStatementObject
+        private class MirroredObject : SingleStatementObject
         {
             /// <summary>
             /// The normal vector of a plane intersecting the origin of the object,
@@ -133,7 +133,7 @@ namespace OSCADSharp
         /// <summary>
         /// Creates an object that's the convex hull of child objects
         /// </summary>
-        internal class HulledObject : MultiStatementObject
+        private class HulledObject : MultiStatementObject
         {
             internal HulledObject(IEnumerable<OSCADObject> children) : base("hull()", children)
             {
@@ -145,7 +145,7 @@ namespace OSCADSharp
         /// <summary>
         /// Creates an object that's the minkowski sum of child objects
         /// </summary>
-        internal class MinkowskiedObject : MultiStatementObject
+        private class MinkowskiedObject : MultiStatementObject
         {
 
             internal MinkowskiedObject(IEnumerable<OSCADObject> children) : base("minkowski()", children)

OSCADSharp/OSCADSharp/OSCADObject.BaseTransform.cs

@@ -18,7 +18,7 @@ namespace OSCADSharp
         /// </summary>
         internal class MultiStatementObject : OSCADObject
         {
-            private string outerStatement;
+            private readonly string outerStatement;
 
             internal MultiStatementObject(string outerStatement, IEnumerable<OSCADObject> children)
             {

OSCADSharp/OSCADSharp/OSCADObject.cs

@@ -20,7 +20,7 @@ namespace OSCADSharp
     public abstract partial class OSCADObject : IBindable
     {
         #region Attributes
-        private int id = Ids.Get();
+        private readonly int id = Ids.Get();
 
         /// <summary>
         /// The unique Id of the object

OSCADSharp/OSCADSharp/Spatial/Matrix.cs

@@ -14,7 +14,7 @@ namespace OSCADSharp.Spatial
     internal class Matrix
     {
         #region Fields/Properties
-        private double[] values;
+        private readonly double[] values;
 
         internal int ColumnCount { get; private set; }
         internal int RowCount { get; private set; }

OSCADSharp/OSCADSharp/Utility/Ids.cs

@@ -12,7 +12,7 @@ namespace OSCADSharp.Utility
     internal static class Ids
     {
         private static int globalId = 0;
-        private static object idLockObject = new object();
+        private readonly static object idLockObject = new object();
 
         /// <summary>
         /// Gets a unique auto-incrementing integer id

OSCADSharp/OSCADSharp/Utility/SingleBlockFormatter.cs

@@ -13,9 +13,9 @@ namespace OSCADSharp.Utility
     /// </summary>
     internal class SingleBlockFormatter
     {
-        private string outerCode;
-        private string innerCode;
-        private string indentationAmount = "    ";
+        private readonly string outerCode;
+        private readonly string innerCode;
+        private readonly string indentationAmount = "    ";
 
         internal SingleBlockFormatter(string outerCode, string innerCode)
         {

OSCADSharp/OSCADSharp/Utility/StatementBuilder.cs

@@ -14,7 +14,7 @@ namespace OSCADSharp.Utility
     internal class StatementBuilder
     {
         private StringBuilder SB { get; set; } = new StringBuilder();
-        private Bindings bindings = null;
+        private readonly Bindings bindings = null;
         
         internal StatementBuilder(Bindings bindings)
         {