From b19edf9579813b1ac2e5430155fb10a2aff49318 Mon Sep 17 00:00:00 2001
From: Friedrich von Never <friedrich@fornever.me>
Date: Mon, 2 Jan 2023 23:08:54 +0100
Subject: [PATCH] (#63) TexEnvironment: convert to a public record

---
 src/WpfMath/Atoms/StyledAtom.cs |   7 +-
 src/WpfMath/TexEnvironment.cs   | 132 +++++++-------------------------
 2 files changed, 32 insertions(+), 107 deletions(-)

diff --git a/src/WpfMath/Atoms/StyledAtom.cs b/src/WpfMath/Atoms/StyledAtom.cs
index 938c12ca..e8b632b5 100644
--- a/src/WpfMath/Atoms/StyledAtom.cs
+++ b/src/WpfMath/Atoms/StyledAtom.cs
@@ -26,9 +26,10 @@ public Atom WithPreviousAtom(DummyAtom? previousAtom) =>
 
         protected override Box CreateBoxCore(TexEnvironment environment)
         {
-            var newEnvironment = environment.Clone();
-            if (this.Foreground != null)
-                newEnvironment.Foreground = this.Foreground;
+            var newEnvironment = environment with
+            {
+                Foreground = this.Foreground ?? environment.Foreground
+            };
             var childBox = this.RowAtom.CreateBox(newEnvironment);
             if (Background != null)
                 childBox.Background = Background;
diff --git a/src/WpfMath/TexEnvironment.cs b/src/WpfMath/TexEnvironment.cs
index 49f6b42b..4f7dede6 100644
--- a/src/WpfMath/TexEnvironment.cs
+++ b/src/WpfMath/TexEnvironment.cs
@@ -1,115 +1,39 @@
 using System.Windows.Media;
 
-namespace WpfMath
+namespace WpfMath;
+
+/// <summary>Specifies current graphical parameters used to create boxes.</summary>
+public sealed record TexEnvironment(
+    TexStyle Style,
+    ITeXFont MathFont,
+    ITeXFont TextFont,
+    Brush? Background = null,
+    Brush? Foreground = null)
 {
-    /// <summary>Specifies current graphical parameters used to create boxes.</summary>
-    public sealed class TexEnvironment
-    {
-        // ID of font that was last used.
-        private int lastFontId = TexFontUtilities.NoFontId;
-
-        internal TexEnvironment(
-            TexStyle style,
-            ITeXFont mathFont,
-            ITeXFont textFont,
-            Brush? background = null,
-            Brush? foreground = null)
-        {
-            if (style == TexStyle.Display || style == TexStyle.Text ||
-                style == TexStyle.Script || style == TexStyle.ScriptScript)
-                this.Style = style;
-            else
-                this.Style = TexStyle.Display;
-
-            this.MathFont = mathFont;
-            TextFont = textFont;
-            this.Background = background;
-            this.Foreground = foreground;
-        }
-
-        internal TexStyle Style
-        {
-            get;
-            private set;
-        }
-
-        internal ITeXFont MathFont
-        {
-            get;
-            private set;
-        }
-
-        internal ITeXFont TextFont { get; }
-
-        internal Brush? Background
-        {
-            get;
-            set;
-        }
+    // ID of font that was last used.
+    private int lastFontId = TexFontUtilities.NoFontId;
 
-        internal Brush? Foreground
-        {
-            get;
-            set;
-        }
-
-        internal int LastFontId
-        {
-            get { return this.lastFontId == TexFontUtilities.NoFontId ? this.MathFont.GetMuFontId() : this.lastFontId; }
-            set { this.lastFontId = value; }
-        }
-
-        internal TexEnvironment GetCrampedStyle()
-        {
-            var newEnvironment = Clone();
-            newEnvironment.Style = (int)this.Style % 2 == 1 ? this.Style : this.Style + 1;
-            return newEnvironment;
-        }
-
-        internal TexEnvironment GetNumeratorStyle()
-        {
-            var newEnvironment = Clone();
-            newEnvironment.Style = this.Style + 2 - 2 * ((int)this.Style / 6);
-            return newEnvironment;
-        }
+    internal int LastFontId
+    {
+        get { return this.lastFontId == TexFontUtilities.NoFontId ? this.MathFont.GetMuFontId() : this.lastFontId; }
+        set { this.lastFontId = value; }
+    }
 
-        internal TexEnvironment GetDenominatorStyle()
-        {
-            var newEnvironment = Clone();
-            newEnvironment.Style = (TexStyle)(2 * ((int)this.Style / 2) + 1 + 2 - 2 * ((int)this.Style / 6));
-            return newEnvironment;
-        }
+    internal TexEnvironment GetCrampedStyle() =>
+        this with { Style = (int)this.Style % 2 == 1 ? this.Style : this.Style + 1 };
 
-        internal TexEnvironment GetRootStyle()
-        {
-            var newEnvironment = Clone();
-            newEnvironment.Style = TexStyle.ScriptScript;
-            return newEnvironment;
-        }
+    internal TexEnvironment GetNumeratorStyle() =>
+        this with { Style = this.Style + 2 - 2 * ((int)this.Style / 6) };
 
-        internal TexEnvironment GetSubscriptStyle()
-        {
-            var newEnvironment = Clone();
-            newEnvironment.Style = (TexStyle)(2 * ((int)this.Style / 4) + 4 + 1);
-            return newEnvironment;
-        }
+    internal TexEnvironment GetDenominatorStyle() =>
+        this with { Style = (TexStyle)(2 * ((int)this.Style / 2) + 1 + 2 - 2 * ((int)this.Style / 6)) };
 
-        internal TexEnvironment GetSuperscriptStyle()
-        {
-            var newEnvironment = Clone();
-            newEnvironment.Style = (TexStyle)(2 * ((int)this.Style / 4) + 4 + ((int)this.Style % 2));
-            return newEnvironment;
-        }
+    internal TexEnvironment GetRootStyle() =>
+        this with { Style = TexStyle.ScriptScript };
 
-        internal TexEnvironment Clone()
-        {
-            return new TexEnvironment(Style, MathFont, TextFont, Background, Foreground);
-        }
+    internal TexEnvironment GetSubscriptStyle() =>
+        this with { Style = (TexStyle)(2 * ((int)this.Style / 4) + 4 + 1) };
 
-        internal void Reset()
-        {
-            this.Background = null;
-            this.Foreground = null;
-        }
-    }
+    internal TexEnvironment GetSuperscriptStyle() =>
+        this with { Style = (TexStyle)(2 * ((int)this.Style / 4) + 4 + (int)this.Style % 2) };
 }