feat: render long noexcept specifications as noexcept(see-below)

include/mrdocs/Support/Handlebars.hpp

@@ -1300,6 +1300,18 @@ MRDOCS_DECL
 bool
 ne_fn(dom::Array const& args);
 
+/** "gt" helper function
+
+    The "gt" helper returns true if the first argument compares
+    greater than the second, via @ref dom::Value's `operator<=>`.
+
+    @param args The two values to compare.
+    @return True if the first value is greater than the second.
+*/
+MRDOCS_DECL
+bool
+gt_fn(dom::Array const& args);
+
 /** "not" helper function
 
     The "not" helper returns true if not all of the values are truthy.

share/mrdocs/addons/generator/adoc/partials/symbol.adoc.hbs

@@ -167,6 +167,16 @@
 | {{> symbol/qualified-name . }}
 {{/each}}
 |===
+{{/if}}
+{{/if}}
+{{! noexcept specification - only when the operand is long enough to
+    be rendered as noexcept(see-below) in the signature. Short
+    operands are shown inline and need no separate section. }}
+{{#if symbol.noexcept}}
+{{#if (gt (len symbol.noexcept) 50)}}
+{{#> markup/dynamic-level-h }}`noexcept` Specification{{/markup/dynamic-level-h~}}
+`noexcept` when `{{slice symbol.noexcept 9 (sub (len symbol.noexcept) 1)}}`.
+
 {{/if}}
 {{/if}}
 {{! Exceptions }}

share/mrdocs/addons/generator/common/partials/symbol/signature/function.hbs

@@ -31,7 +31,13 @@
 {{~#if isConst}} const{{/if~}}
 {{#if isVolatile}} volatile{{/if~}}
 {{#if refQualifier}} {{refQualifier}}{{/if~}}
-{{#if noexcept}} {{noexcept}}{{/if~}}
+{{~#if noexcept~}}
+    {{~! Specs with operands longer than 40 characters (full string > 50,
+         accounting for the "noexcept(" and ")" wrappers) are rendered as
+         `noexcept(see-below)` plus a dedicated specification section;
+         shorter ones are shown inline. ~}}
+    {{~#if (gt (len noexcept) 50)}} noexcept({{#>markup/em}}see-below{{/markup/em}}){{else}} {{noexcept}}{{/if~}}
+{{~/if~}}
 {{#if (eq funcClass "normal")}}{{>type/declarator-suffix returnType}}{{/if~}}
 {{#if requires}}
 

share/mrdocs/addons/generator/common/partials/type/declarator-suffix.hbs

@@ -37,8 +37,10 @@
     {{~#if cv-qualifiers}} {{cv-qualifiers}}{{/if~}}
     {{! Refqualifiers as "&" or "&&" ~}}
     {{#if (eq refQualifier "lvalue")}} &{{else if (eq refQualifier "rvalue")}} &&{{/if~}}
-    {{! Exception spec as literal string ~}}
-    {{#if exceptionSpec}} {{exceptionSpec}}{{/if~}}
+    {{! noexcept specification with "see-below" placeholder for long operands ~}}
+    {{~#if exceptionSpec~}}
+        {{~#if (gt (len exceptionSpec) 50)}} noexcept({{#>markup/em}}see-below{{/markup/em}}){{else}} {{exceptionSpec}}{{/if~}}
+    {{~/if~}}
     {{! Declarator suffix of the return type ~}}
     {{~>type/declarator-suffix returnType link-components-impl=link-components-impl~}}
 {{/if}}

share/mrdocs/addons/generator/html/partials/symbol.html.hbs

@@ -231,6 +231,17 @@
 {{/if}}
 </div>
 
+{{/if}}
+{{! noexcept specification - only when the operand is long enough to
+    be rendered as noexcept(see-below) in the signature. Short
+    operands are shown inline and need no separate section. }}
+{{#if symbol.noexcept}}
+{{#if (gt (len symbol.noexcept) 50)}}
+<div>
+{{#> markup/dynamic-level-h level=2 }}<code>noexcept</code> Specification{{/markup/dynamic-level-h~}}
+<p><code>noexcept</code> when <code>{{slice symbol.noexcept 9 (sub (len symbol.noexcept) 1)}}</code>.</p>
+</div>
+{{/if}}
 {{/if}}
 {{! Exceptions }}
 {{#if symbol.doc.exceptions}}

src/lib/Support/Handlebars.cpp

@@ -3835,6 +3835,7 @@ registerAntoraHelpers(Handlebars& hbs)
     hbs.registerHelper("and", dom::makeVariadicInvocable(and_fn));
     hbs.registerHelper("detag", dom::makeInvocable(detag_fn));
     hbs.registerHelper("eq", dom::makeVariadicInvocable(eq_fn));
+    hbs.registerHelper("gt", dom::makeVariadicInvocable(gt_fn));
     hbs.registerHelper("increment", dom::makeInvocable(increment_fn));
     hbs.registerHelper("ne", dom::makeVariadicInvocable(ne_fn));
     hbs.registerHelper("not", dom::makeVariadicInvocable(not_fn));
@@ -3847,6 +3848,7 @@ registerLogicalHelpers(Handlebars& hbs)
 {
     hbs.registerHelper("and", dom::makeVariadicInvocable(and_fn));
     hbs.registerHelper("eq", dom::makeVariadicInvocable(eq_fn));
+    hbs.registerHelper("gt", dom::makeVariadicInvocable(gt_fn));
     hbs.registerHelper("ne", dom::makeVariadicInvocable(ne_fn));
     hbs.registerHelper("not", dom::makeVariadicInvocable(not_fn));
     hbs.registerHelper("or", dom::makeVariadicInvocable(or_fn));
@@ -3909,6 +3911,18 @@ ne_fn(dom::Array const& args) {
     return !eq_fn(args);
 }
 
+// Greater-than comparison via `operator<=>` on `dom::Value`.
+bool
+gt_fn(dom::Array const& args) {
+    // args carries trailing options, so we need at least two real
+    // arguments plus that one.
+    if (args.size() < 3)
+    {
+        return false;
+    }
+    return args.get(0) > args.get(1);
+}
+
 bool
 not_fn(dom::Array const& args) {
     std::size_t const n = args.size();

src/test/lib/Metadata/NoexceptInfo.cpp

@@ -0,0 +1,118 @@
+//
+// Licensed under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// Copyright (c) 2026 Gennaro Prota (gennaro.prota@gmail.com)
+//
+// Official repository: https://github.com/cppalliance/mrdocs
+//
+
+#include <mrdocs/Dom/String.hpp>
+#include <mrdocs/Metadata/Specifiers/NoexceptInfo.hpp>
+#include <test_suite/test_suite.hpp>
+
+namespace mrdocs {
+namespace {
+
+// Helpers to build the specs in one line per test.
+
+NoexceptInfo
+makeNoexcept(
+    bool const implicit,
+    NoexceptKind const kind,
+    std::string operand = {})
+{
+    NoexceptInfo info;
+    info.Implicit = implicit;
+    info.Kind = kind;
+    info.Operand = std::move(operand);
+    return info;
+}
+
+// ------------------------------------------------------------------
+
+struct NoexceptInfoTest
+{
+    // -- toString(NoexceptInfo) ----------------------------------
+
+    void test_noexcept_implicit_is_skipped()
+    {
+        NoexceptInfo const info = makeNoexcept(true, NoexceptKind::True);
+        BOOST_TEST(toString(info).get() == "");
+    }
+
+    void test_noexcept_implicit_shown_when_requested()
+    {
+        NoexceptInfo const info = makeNoexcept(true, NoexceptKind::True);
+        BOOST_TEST(toString(info, false, true).get() == "noexcept");
+    }
+
+    void test_noexcept_dependent_empty_operand()
+    {
+        NoexceptInfo const info = makeNoexcept(false, NoexceptKind::Dependent);
+        BOOST_TEST(toString(info).get() == "");
+    }
+
+    void test_noexcept_dependent_with_operand()
+    {
+        NoexceptInfo const info = makeNoexcept(
+            false, NoexceptKind::Dependent, "sizeof(T) > 4");
+        BOOST_TEST(toString(info).get() == "noexcept(sizeof(T) > 4)");
+    }
+
+    void test_noexcept_false_resolved_drops_operand()
+    {
+        NoexceptInfo const info = makeNoexcept(
+            false, NoexceptKind::False, "false");
+        BOOST_TEST(toString(info, true).get() == "");
+    }
+
+    void test_noexcept_false_with_operand()
+    {
+        NoexceptInfo const info = makeNoexcept(
+            false, NoexceptKind::False, "false");
+        BOOST_TEST(toString(info).get() == "noexcept(false)");
+    }
+
+    void test_noexcept_true_resolved_drops_operand()
+    {
+        NoexceptInfo const info = makeNoexcept(
+            false, NoexceptKind::True, "true");
+        BOOST_TEST(toString(info, true).get() == "noexcept");
+    }
+
+    void test_noexcept_true_empty_operand()
+    {
+        NoexceptInfo const info = makeNoexcept(false, NoexceptKind::True);
+        BOOST_TEST(toString(info).get() == "noexcept");
+    }
+
+    void test_noexcept_true_with_operand()
+    {
+        NoexceptInfo const info = makeNoexcept(
+            false, NoexceptKind::True, "true");
+        BOOST_TEST(toString(info).get() == "noexcept(true)");
+    }
+
+    // -- runner --------------------------------------------------
+
+    void run()
+    {
+        test_noexcept_implicit_is_skipped();
+        test_noexcept_implicit_shown_when_requested();
+        test_noexcept_dependent_empty_operand();
+        test_noexcept_dependent_with_operand();
+        test_noexcept_false_resolved_drops_operand();
+        test_noexcept_false_with_operand();
+        test_noexcept_true_resolved_drops_operand();
+        test_noexcept_true_empty_operand();
+        test_noexcept_true_with_operand();
+    }
+};
+
+} // (unnamed)
+
+TEST_SUITE(NoexceptInfoTest, "clang.mrdocs.Metadata.NoexceptInfo");
+
+} // mrdocs

test-files/golden-tests/symbols/function/noexcept.adoc

@@ -0,0 +1,159 @@
+= Reference
+:mrdocs:
+
+[#index]
+== Global namespace
+
+=== Functions
+
+[cols=1]
+|===
+| Name
+| link:#f1[`f1`] 
+| link:#f2[`f2`] 
+| link:#f3[`f3`] 
+| link:#f4[`f4`] 
+| link:#f5[`f5`] 
+| link:#f6[`f6`] 
+|===
+
+=== Variables
+
+[cols=1]
+|===
+| Name
+| link:#is_nothrow_move_assignable_v[`is_nothrow_move_assignable_v`] 
+| link:#is_nothrow_move_constructible_v[`is_nothrow_move_constructible_v`] 
+| link:#is_nothrow_swappable_v[`is_nothrow_swappable_v`] 
+|===
+
+[#f1]
+== f1
+
+=== Synopsis
+
+Declared in `<noexcept.cpp>`
+
+[source,cpp,subs="verbatim,replacements,macros,-callouts"]
+----
+void
+f1() noexcept;
+----
+
+[#f2]
+== f2
+
+=== Synopsis
+
+Declared in `<noexcept.cpp>`
+
+[source,cpp,subs="verbatim,replacements,macros,-callouts"]
+----
+void
+f2() noexcept(true);
+----
+
+[#f3]
+== f3
+
+=== Synopsis
+
+Declared in `<noexcept.cpp>`
+
+[source,cpp,subs="verbatim,replacements,macros,-callouts"]
+----
+void
+f3() noexcept(false);
+----
+
+[#f4]
+== f4
+
+=== Synopsis
+
+Declared in `<noexcept.cpp>`
+
+[source,cpp,subs="verbatim,replacements,macros,-callouts"]
+----
+template<typename T>
+void
+f4(T&) noexcept(is_nothrow_swappable_v<T>);
+----
+
+[#f5]
+== f5
+
+=== Synopsis
+
+Declared in `<noexcept.cpp>`
+
+[source,cpp,subs="verbatim,replacements,macros,-callouts"]
+----
+template<typename T>
+void
+f5(
+    T a,
+    T b) noexcept(noexcept(a + b));
+----
+
+[#f6]
+== f6
+
+=== Synopsis
+
+Declared in `<noexcept.cpp>`
+
+[source,cpp,subs="verbatim,replacements,macros,-callouts"]
+----
+template<typename T>
+void
+f6(
+    T&,
+    T&) noexcept(_see-below_);
+----
+
+=== `noexcept` Specification
+
+`noexcept` when `is_nothrow_move_constructible_v<T> && is_nothrow_move_assignable_v<T>`.
+
+[#is_nothrow_move_assignable_v]
+== is_nothrow_move_assignable_v
+
+=== Synopsis
+
+Declared in `<noexcept.cpp>`
+
+[source,cpp,subs="verbatim,replacements,macros,-callouts"]
+----
+template<typename T>
+inline constexpr bool is_nothrow_move_assignable_v = false;
+----
+
+[#is_nothrow_move_constructible_v]
+== is_nothrow_move_constructible_v
+
+=== Synopsis
+
+Declared in `<noexcept.cpp>`
+
+[source,cpp,subs="verbatim,replacements,macros,-callouts"]
+----
+template<typename T>
+inline constexpr bool is_nothrow_move_constructible_v = false;
+----
+
+[#is_nothrow_swappable_v]
+== is_nothrow_swappable_v
+
+=== Synopsis
+
+Declared in `<noexcept.cpp>`
+
+[source,cpp,subs="verbatim,replacements,macros,-callouts"]
+----
+template<typename T>
+inline constexpr bool is_nothrow_swappable_v = false;
+----
+
+
+[.small]#Created with https://www.mrdocs.com[MrDocs]#