LibWeb/CSS: Implement CSSMathClamp

As the final CSSMathFoo class, this makes the serialization test finally
run instead of crashing.

Libraries/LibWeb/CSS/CSSMathClamp.cpp

@@ -0,0 +1,105 @@
+/*
+ * Copyright (c) 2025, Sam Atkins <sam@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include "CSSMathClamp.h"
+#include <LibWeb/Bindings/CSSMathClampPrototype.h>
+#include <LibWeb/Bindings/Intrinsics.h>
+#include <LibWeb/CSS/CSSMathNegate.h>
+#include <LibWeb/CSS/CSSNumericArray.h>
+#include <LibWeb/WebIDL/DOMException.h>
+#include <LibWeb/WebIDL/ExceptionOr.h>
+
+namespace Web::CSS {
+
+GC_DEFINE_ALLOCATOR(CSSMathClamp);
+
+GC::Ref<CSSMathClamp> CSSMathClamp::create(JS::Realm& realm, NumericType type, GC::Ref<CSSNumericValue> lower, GC::Ref<CSSNumericValue> value, GC::Ref<CSSNumericValue> upper)
+{
+    return realm.create<CSSMathClamp>(realm, move(type), move(lower), move(value), move(upper));
+}
+
+// https://drafts.css-houdini.org/css-typed-om-1/#dom-cssmathclamp-cssmathclamp
+WebIDL::ExceptionOr<GC::Ref<CSSMathClamp>> CSSMathClamp::construct_impl(JS::Realm& realm, CSSNumberish lower, CSSNumberish value, CSSNumberish upper)
+{
+    // The CSSMathClamp(lower, value, upper) constructor must, when called, perform the following steps:
+    // 1. Replace lower, value, and upper with the result of rectifying a numberish value for each.
+    auto lower_rectified = rectify_a_numberish_value(realm, lower);
+    auto value_rectified = rectify_a_numberish_value(realm, value);
+    auto upper_rectified = rectify_a_numberish_value(realm, upper);
+
+    // 2. Let type be the result of adding the types of lower, value, and upper. If type is failure, throw a TypeError.
+    auto type = lower_rectified->type()
+                    .added_to(value_rectified->type())
+                    .map([&](auto& type) { return type.added_to(upper_rectified->type()); });
+    if (!type.has_value()) {
+        return WebIDL::SimpleException { WebIDL::SimpleExceptionType::TypeError, "Cannot create a CSSMathClamp with values of incompatible types"sv };
+    }
+
+    // 3. Return a new CSSMathClamp whose lower, value, and upper internal slots are set to lower, value, and upper, respectively.
+    return CSSMathClamp::create(realm, type->release_value(), move(lower_rectified), move(value_rectified), move(upper_rectified));
+}
+
+CSSMathClamp::CSSMathClamp(JS::Realm& realm, NumericType type, GC::Ref<CSSNumericValue> lower, GC::Ref<CSSNumericValue> value, GC::Ref<CSSNumericValue> upper)
+    : CSSMathValue(realm, Bindings::CSSMathOperator::Clamp, move(type))
+    , m_lower(move(lower))
+    , m_value(move(value))
+    , m_upper(move(upper))
+{
+}
+
+CSSMathClamp::~CSSMathClamp() = default;
+
+void CSSMathClamp::initialize(JS::Realm& realm)
+{
+    WEB_SET_PROTOTYPE_FOR_INTERFACE(CSSMathClamp);
+    Base::initialize(realm);
+}
+
+void CSSMathClamp::visit_edges(Visitor& visitor)
+{
+    Base::visit_edges(visitor);
+    visitor.visit(m_lower);
+    visitor.visit(m_value);
+    visitor.visit(m_upper);
+}
+
+// https://drafts.css-houdini.org/css-typed-om-1/#serialize-a-cssmathvalue
+String CSSMathClamp::serialize_math_value(Nested, Parens) const
+{
+    // AD-HOC: The spec is missing serialization rules for CSSMathClamp: https://github.com/w3c/css-houdini-drafts/issues/1152
+    StringBuilder s;
+    s.append("clamp("sv);
+    s.append(m_lower->to_string({ .nested = true, .parenless = true }));
+    s.append(", "sv);
+    s.append(m_value->to_string({ .nested = true, .parenless = true }));
+    s.append(", "sv);
+    s.append(m_upper->to_string({ .nested = true, .parenless = true }));
+    s.append(")"sv);
+    return s.to_string_without_validation();
+}
+
+// https://drafts.css-houdini.org/css-typed-om-1/#dom-cssmathclamp-lower
+GC::Ref<CSSNumericValue> CSSMathClamp::lower() const
+{
+    // AD-HOC: No spec definition.
+    return m_lower;
+}
+
+// https://drafts.css-houdini.org/css-typed-om-1/#dom-cssmathclamp-value
+GC::Ref<CSSNumericValue> CSSMathClamp::value() const
+{
+    // AD-HOC: No spec definition.
+    return m_value;
+}
+
+// https://drafts.css-houdini.org/css-typed-om-1/#dom-cssmathclamp-upper
+GC::Ref<CSSNumericValue> CSSMathClamp::upper() const
+{
+    // AD-HOC: No spec definition.
+    return m_upper;
+}
+
+}