From a5418218f8252e70bb8d1ef0f64e0e73b7793607 Mon Sep 17 00:00:00 2001
From: Rafael Vuijk <r.vuijk@sownet.nl>
Date: Sat, 24 Oct 2026 06:12:59 +0000
Subject: [PATCH] Register the notebook LaTeX formatters by reflection, and
 drop polyfill.io

AngouriMath's extension.dib, the C# script NuGet loads with the package, began
`using AngouriMath;`. An F# notebook loads it into the C# kernel, which has no
reference to AngouriMath, so the first output of every F# notebook was
CS0246. It now finds ILatexizeable, EDecimal, EInteger and ERational among the
loaded assemblies and registers its formatters on those types, which works
from either kernel. Measured in the binder/Dockerfile image with the packages
packed locally: from F#, the script loads and says so, and derivative "x" "x^3"
is 3 x^2 in LaTeX; from C#, an entity and an ERational render as before.

And both this script and AngouriMath.Interactive's F# extension put
<script src='https://polyfill.io/...'> into every HTML output, a domain taken
over in 2024 and used to serve malicious code. MathJax 3 needs no polyfill in
a current browser; the line is gone, from the tests' expected HTML too.

Fixes https://github.com/asc-community/AngouriMath/issues/2109.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012sonx8iAspMiwRwokT1Ura
---
 Sources/AngouriMath/extension.dib             | 48 +++++++++----------
 .../InteractiveWrapperUnitTests/HtmlOutput.fs |  3 --
 .../KernelExtension.fs                        |  1 -
 3 files changed, 24 insertions(+), 28 deletions(-)

diff --git a/Sources/AngouriMath/extension.dib b/Sources/AngouriMath/extension.dib
index 2b597c221..20b1d6e95 100644
--- a/Sources/AngouriMath/extension.dib
+++ b/Sources/AngouriMath/extension.dib
@@ -1,36 +1,36 @@
 #!csharp
 
-using AngouriMath;
-using AngouriMath.Extensions;
-using Microsoft.DotNet.Interactive;
+// The LaTeX formatters, registered by reflection rather than against AngouriMath's types: an F# notebook loads
+// this script into the C# kernel, which has no reference to AngouriMath, and `using AngouriMath;` there was a
+// compile error at the top of every F# notebook. https://github.com/asc-community/AngouriMath/issues/2109
+using System;
+using System.Linq;
 using Microsoft.DotNet.Interactive.Formatting;
 
-static void RegisterLatex<T>(Func<T, string> latexer)
-{
-    Formatter.Register<T>(
-        t => $"$${latexer(t)}$$", 
-        "text/latex");
+static Type FindType(string assembly, string name)
+    => AppDomain.CurrentDomain.GetAssemblies().FirstOrDefault(a => a.GetName().Name == assembly)?.GetType(name);
 
-    Formatter.Register<T>(
-        t => $@"
-<script src='https://polyfill.io/v3/polyfill.min.js?features=es6'></script>
+static void RegisterLatex(Type type, Func<object, string> latexer)
+{
+    Formatter.Register(type, (o, writer) => writer.Write($"$${latexer(o)}$$"), "text/latex");
+    Formatter.Register(type, (o, writer) => writer.Write($@"
 <script id='MathJax-script' async src='https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js'></script>
-\[{latexer(t)}\]",
-        "text/html"
-    );
-
-    Formatter.SetPreferredMimeTypesFor(typeof(T), "text/latex");
+\[{latexer(o)}\]"), "text/html");
+    Formatter.SetPreferredMimeTypesFor(type, "text/latex");
 }
 
-Formatter.SetPreferredMimeTypesFor(typeof(PeterO.Numbers.EDecimal), "text/plain");
-Formatter.Register<PeterO.Numbers.EDecimal>(o => o.ToString(), "text/plain");
+foreach (var name in new[] { "PeterO.Numbers.EDecimal", "PeterO.Numbers.EInteger" })
+    if (FindType("Numbers", name) is { } plain)
+    {
+        Formatter.SetPreferredMimeTypesFor(plain, "text/plain");
+        Formatter.Register(plain, (o, writer) => writer.Write(o.ToString()), "text/plain");
+    }
 
-Formatter.SetPreferredMimeTypesFor(typeof(PeterO.Numbers.EInteger), "text/plain");
-Formatter.Register<PeterO.Numbers.EInteger>(o => o.ToString(), "text/plain");
+if (FindType("AngouriMath", "AngouriMath.Core.ILatexizeable") is { } latexizeable
+    && latexizeable.GetMethod("Latexize", Type.EmptyTypes) is { } latexize)
+    RegisterLatex(latexizeable, o => (string)latexize.Invoke(o, null));
 
-RegisterLatex<AngouriMath.Core.ILatexizeable>(o => o.Latexize());
-
-RegisterLatex<PeterO.Numbers.ERational>(o => $@"\frac{{{o.Numerator}}}{{{o.Denominator}}}");
+if (FindType("Numbers", "PeterO.Numbers.ERational") is { } rational)
+    RegisterLatex(rational, o => $@"\frac{{{rational.GetProperty("Numerator").GetValue(o)}}}{{{rational.GetProperty("Denominator").GetValue(o)}}}");
 
 "Extensions for LaTeX loaded!"
-
diff --git a/Sources/Tests/InteractiveWrapperUnitTests/HtmlOutput.fs b/Sources/Tests/InteractiveWrapperUnitTests/HtmlOutput.fs
index e7d9673aa..17a7869e4 100644
--- a/Sources/Tests/InteractiveWrapperUnitTests/HtmlOutput.fs
+++ b/Sources/Tests/InteractiveWrapperUnitTests/HtmlOutput.fs
@@ -18,7 +18,6 @@ let ``Latex with magic ILatexizeable html`` () =
     let entity = parsed "x / 2"
     let html = entity.ToDisplayString("text/html")
     Assert.Equal(@"
-<script src='https://polyfill.io/v3/polyfill.min.js?features=es6'></script>
 <script id='MathJax-script' async src='https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js'></script>
 \[\frac{x}{2}\]", html)
 
@@ -29,7 +28,6 @@ let ``Latex with magic ERational for html`` () =
     let entity = (("2 / 3" |> asNumber) :?> Entity.Number.Rational).ERational
     let html = entity.ToDisplayString("text/html")
     Assert.Equal(@"
-<script src='https://polyfill.io/v3/polyfill.min.js?features=es6'></script>
 <script id='MathJax-script' async src='https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js'></script>
 \[\frac{2}{3}\]", html)
 
@@ -40,7 +38,6 @@ let ``Latex with magic ERational multi-char for html`` () =
     let entity = (("23 / 36" |> asNumber) :?> Entity.Number.Rational).ERational
     let html = entity.ToDisplayString("text/html")
     Assert.Equal(@"
-<script src='https://polyfill.io/v3/polyfill.min.js?features=es6'></script>
 <script id='MathJax-script' async src='https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js'></script>
 \[\frac{23}{36}\]", html)
 
diff --git a/Sources/Wrappers/AngouriMath.Interactive/KernelExtension.fs b/Sources/Wrappers/AngouriMath.Interactive/KernelExtension.fs
index e7dd23f72..b12e0af82 100644
--- a/Sources/Wrappers/AngouriMath.Interactive/KernelExtension.fs
+++ b/Sources/Wrappers/AngouriMath.Interactive/KernelExtension.fs
@@ -20,7 +20,6 @@ type KernelExtension() =
 
             // register text/html
             (fun o -> $@"
-<script src='https://polyfill.io/v3/polyfill.min.js?features=es6'></script>
 <script id='MathJax-script' async src='https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js'></script>
 \[{latexizer o}\]")
             |> (fun f -> new Func<'a, string>(f))