From 87d07523d8b563813043f169d166143bbcb36c34 Mon Sep 17 00:00:00 2001
From: Vinnie Falco <vinnie.falco@gmail.com>
Date: Thu, 15 Jun 2023 05:46:49 -0700
Subject: [PATCH] chore: better bitcoding for doc nodes

---
 include/mrdox/Metadata/Javadoc.hpp | 147 +++++++++++++++++------------
 source/-XML/XMLWriter.cpp          |   4 +-
 source/-XML/XMLWriter.hpp          |   2 +-
 source/-adoc/AdocWriter.cpp        |   4 +-
 source/-adoc/AdocWriter.hpp        |   2 +-
 source/AST/AnyBlock.hpp            |  50 +++-------
 source/AST/BitcodeWriter.cpp       | 110 ++++++++-------------
 source/AST/ParseJavadoc.cpp        |   2 +-
 8 files changed, 148 insertions(+), 173 deletions(-)

diff --git a/include/mrdox/Metadata/Javadoc.hpp b/include/mrdox/Metadata/Javadoc.hpp
index 23a11c822..1ce692667 100644
--- a/include/mrdox/Metadata/Javadoc.hpp
+++ b/include/mrdox/Metadata/Javadoc.hpp
@@ -97,17 +97,24 @@ struct Node
 
     virtual ~Node() = default;
 
-    bool operator==(const Node&)
-        const noexcept = default;
-
-    virtual bool equals(
-        const Node& other) const noexcept
+    bool operator==(const Node&)const noexcept = default;
+    virtual bool equals(const Node& other) const noexcept
     {
         return kind == other.kind;
     }
 };
 
-/** A string of plain text.
+//------------------------------------------------
+//
+// Text nodes
+//
+//------------------------------------------------
+
+/** A Node containing a string of text.
+
+    There will be no newlines in the text. Otherwise,
+    this would be represented as multiple text nodes
+    within a Paragraph node.
 */
 struct Text : Node
 {
@@ -117,15 +124,13 @@ struct Text : Node
 
     explicit
     Text(
-        String string_ = String())
+        String string_ = String()) noexcept
         : Node(Kind::text)
         , string(std::move(string_))
     {
     }
 
-    bool operator==(const Text&)
-        const noexcept = default;
-
+    bool operator==(const Text&) const noexcept = default;
     bool equals(const Node& other) const noexcept override
     {
         return kind == other.kind &&
@@ -144,31 +149,35 @@ struct Text : Node
 
 /** A piece of style text.
 */
-struct StyledText : Text
+struct Styled : Text
 {
     Style style;
 
     static constexpr Kind static_kind = Kind::styled;
 
-    StyledText(
+    Styled(
         String string_ = String(),
-        Style style_ = Style::none)
+        Style style_ = Style::none) noexcept
         : Text(std::move(string_), Kind::styled)
         , style(style_)
     {
     }
 
-    bool operator==(const StyledText&)
-        const noexcept = default;
-
-    bool equals(const Node& other) const noexcept override
+    bool operator==(Styled const&) const noexcept = default;
+    bool equals(Node const& other) const noexcept override
     {
         return kind == other.kind &&
-            *this == static_cast<const StyledText&>(other);
+            *this == static_cast<const Styled&>(other);
     }
 
 };
 
+//------------------------------------------------
+//
+// Block nodes
+//
+//------------------------------------------------
+
 /** A piece of block content
 
     The top level is a list of blocks.
@@ -220,15 +229,13 @@ struct Heading : Block
     String string;
 
     Heading(
-        String string_ = String())
+        String string_ = String()) noexcept
         : Block(Kind::heading)
         , string(std::move(string_))
     {
     }
 
-    bool operator==(const Heading&)
-        const noexcept = default;
-
+    bool operator==(Heading const&) const noexcept = default;
     bool equals(const Node& other) const noexcept override
     {
         return kind == other.kind &&
@@ -247,9 +254,7 @@ struct Paragraph : Block
     {
     }
 
-    bool operator==(const Paragraph&)
-        const noexcept = default;
-
+    bool operator==(const Paragraph&) const noexcept = default;
     bool equals(const Node& other) const noexcept override
     {
         return kind == other.kind &&
@@ -260,7 +265,7 @@ struct Paragraph : Block
     explicit
     Paragraph(
         Kind kind,
-        List<Text> children_ = {})
+        List<Text> children_ = {}) noexcept
         : Block(kind, std::move(children_))
     {
     }
@@ -277,9 +282,7 @@ struct Brief : Paragraph
     {
     }
 
-    bool operator==(const Brief&)
-        const noexcept = default;
-
+    bool operator==(const Brief&) const noexcept = default;
     bool equals(const Node& other) const noexcept override
     {
         return kind == other.kind &&
@@ -287,7 +290,7 @@ struct Brief : Paragraph
     }
 };
 
-/** Documentation for an admonition
+/** An admonition.
 */
 struct Admonition : Paragraph
 {
@@ -295,15 +298,13 @@ struct Admonition : Paragraph
 
     explicit
     Admonition(
-        Admonish style_ = Admonish::none)
+        Admonish style_ = Admonish::none) noexcept
         : Paragraph(Kind::admonition)
         , style(style_)
     {
     }
 
-    bool operator==(const Admonition&)
-        const noexcept = default;
-
+    bool operator==(const Admonition&) const noexcept = default;
     bool equals(const Node& other) const noexcept override
     {
         return kind == other.kind &&
@@ -320,14 +321,12 @@ struct Code : Paragraph
 
     static constexpr Kind static_kind = Kind::code;
 
-    Code()
+    Code() noexcept
         : Paragraph(Kind::code)
     {
     }
 
-    bool operator==(const Code&)
-        const noexcept = default;
-
+    bool operator==(const Code&) const noexcept = default;
     bool equals(const Node& other) const noexcept override
     {
         return kind == other.kind &&
@@ -366,52 +365,84 @@ struct Param : Paragraph
     }
 };
 
-/** Documentation for a template parameter
+
+/** Documentation for a function return type
 */
-struct TParam : Paragraph
+struct Returns : Paragraph
 {
-    String name;
-
-    static constexpr Kind static_kind = Kind::tparam;
+    static constexpr Kind static_kind = Kind::returns;
 
-    TParam()
-        : Paragraph(Kind::tparam)
+    Returns()
+        : Paragraph(Kind::returns)
     {
     }
 
-    bool operator==(const TParam&)
+    bool operator==(const Returns&)
         const noexcept = default;
 
     bool equals(const Node& other) const noexcept override
     {
         return kind == other.kind &&
-            *this == static_cast<const TParam&>(other);
+            *this == static_cast<const Returns&>(other);
     }
 };
-
-/** Documentation for a function return type
+/** Documentation for a template parameter
 */
-struct Returns : Paragraph
+struct TParam : Paragraph
 {
-    static constexpr Kind static_kind = Kind::returns;
+    String name;
 
-    Returns()
-        : Paragraph(Kind::returns)
+    static constexpr Kind static_kind = Kind::tparam;
+
+    TParam()
+        : Paragraph(Kind::tparam)
     {
     }
 
-    bool operator==(const Returns&)
-        const noexcept = default;
-
+    bool operator==(const TParam&) const noexcept = default;
     bool equals(const Node& other) const noexcept override
     {
         return kind == other.kind &&
-            *this == static_cast<const Returns&>(other);
+            *this == static_cast<const TParam&>(other);
     }
 };
 
 //------------------------------------------------
 
+template<class F, class... Args>
+constexpr
+auto
+visit(
+    Kind kind,
+    F&& f, Args&&... args)
+{
+    switch(kind)
+    {
+    case Kind::admonition:
+        return f.template operator()<Admonition>(std::forward<Args>(args)...);
+    case Kind::brief:
+        return f.template operator()<Brief>(std::forward<Args>(args)...);
+    case Kind::code:
+        return f.template operator()<Code>(std::forward<Args>(args)...);
+    case Kind::heading:
+        return f.template operator()<Heading>(std::forward<Args>(args)...);
+    case Kind::paragraph:
+        return f.template operator()<Paragraph>(std::forward<Args>(args)...);
+    case Kind::param:
+        return f.template operator()<Param>(std::forward<Args>(args)...);
+    case Kind::returns:
+        return f.template operator()<Returns>(std::forward<Args>(args)...);
+    case Kind::styled:
+        return f.template operator()<Styled>(std::forward<Args>(args)...);
+    case Kind::text:
+        return f.template operator()<Text>(std::forward<Args>(args)...);
+    case Kind::tparam:
+        return f.template operator()<TParam>(std::forward<Args>(args)...);
+    default:
+        return f.template operator()<void>(std::forward<Args>(args)...);
+    }
+}
+
 template<class F, class... Args>
 constexpr
 auto
@@ -443,7 +474,7 @@ visit(
         return f(static_cast<Returns const&>(node),
             std::forward<Args>(args)...);
     case Kind::styled:
-        return f(static_cast<StyledText const&>(node),
+        return f(static_cast<Styled const&>(node),
             std::forward<Args>(args)...);
     case Kind::text:
         return f(static_cast<Text const&>(node),
diff --git a/source/-XML/XMLWriter.cpp b/source/-XML/XMLWriter.cpp
index b4e9631f8..a2d105235 100644
--- a/source/-XML/XMLWriter.cpp
+++ b/source/-XML/XMLWriter.cpp
@@ -605,7 +605,7 @@ writeNode(
         writeText(static_cast<doc::Text const&>(node));
         break;
     case doc::Kind::styled:
-        writeStyledText(static_cast<doc::StyledText const&>(node));
+        writeStyledText(static_cast<doc::Styled const&>(node));
         break;
     case doc::Kind::heading:
         writeHeading(static_cast<doc::Heading const&>(node));
@@ -661,7 +661,7 @@ writeText(
 void
 XMLWriter::
 writeStyledText(
-    doc::StyledText const& node)
+    doc::Styled const& node)
 {
     tags_.write(toString(node.style), node.string);
 }
diff --git a/source/-XML/XMLWriter.hpp b/source/-XML/XMLWriter.hpp
index 8b0b10c70..229b25884 100644
--- a/source/-XML/XMLWriter.hpp
+++ b/source/-XML/XMLWriter.hpp
@@ -86,7 +86,7 @@ class XMLWriter
     void writeNode(doc::Node const& node);
     void writeBrief(doc::Paragraph const& node);
     void writeText(doc::Text const& node);
-    void writeStyledText(doc::StyledText const& node);
+    void writeStyledText(doc::Styled const& node);
     void writeHeading(doc::Heading const& node);
     void writeParagraph(doc::Paragraph const& node, llvm::StringRef tag = "");
     void writeAdmonition(doc::Admonition const& node);
diff --git a/source/-adoc/AdocWriter.cpp b/source/-adoc/AdocWriter.cpp
index f9c087b5a..718b74371 100644
--- a/source/-adoc/AdocWriter.cpp
+++ b/source/-adoc/AdocWriter.cpp
@@ -633,7 +633,7 @@ writeNode(
         writeNode(static_cast<doc::Text const&>(node));
         return;
     case doc::Kind::styled:
-        writeNode(static_cast<doc::StyledText const&>(node));
+        writeNode(static_cast<doc::Styled const&>(node));
         return;
 #if 0
     case doc::Node::block:
@@ -687,7 +687,7 @@ writeNode(
 void
 AdocWriter::
 writeNode(
-    doc::StyledText const& node)
+    doc::Styled const& node)
 {
     switch(node.style)
     {
diff --git a/source/-adoc/AdocWriter.hpp b/source/-adoc/AdocWriter.hpp
index 83ac3dc24..a0bc20e6c 100644
--- a/source/-adoc/AdocWriter.hpp
+++ b/source/-adoc/AdocWriter.hpp
@@ -114,7 +114,7 @@ class AdocWriter
     void writeNode(doc::Node const& node);
     void writeNode(doc::Block const& node);
     void writeNode(doc::Text const& node);
-    void writeNode(doc::StyledText const& node);
+    void writeNode(doc::Styled const& node);
     void writeNode(doc::Paragraph const& node);
     void writeNode(doc::Admonition const& node);
     void writeNode(doc::Code const& node);
diff --git a/source/AST/AnyBlock.hpp b/source/AST/AnyBlock.hpp
index 7b5804f7b..9949dc6b4 100644
--- a/source/AST/AnyBlock.hpp
+++ b/source/AST/AnyBlock.hpp
@@ -103,41 +103,19 @@ class JavadocNodesBlock
             doc::Kind kind{};
             if(auto err = decodeRecord(R, kind, Blob))
                 return err;
-            switch(kind)
-            {
-            case doc::Kind::text:
-                nodes.emplace_back(std::make_unique<doc::Text>());
-                return Error::success();
-            case doc::Kind::styled:
-                nodes.emplace_back(std::make_unique<doc::StyledText>());
-                return Error::success();
-            case doc::Kind::heading:
-                nodes.emplace_back(std::make_unique<doc::Heading>());
-                return Error::success();
-            case doc::Kind::paragraph:
-                nodes.emplace_back(std::make_unique<doc::Paragraph>());
-                return Error::success();
-            case doc::Kind::brief:
-                nodes.emplace_back(std::make_unique<doc::Brief>());
-                return Error::success();
-            case doc::Kind::admonition:
-                nodes.emplace_back(std::make_unique<doc::Admonition>());
-                return Error::success();
-            case doc::Kind::code:
-                nodes.emplace_back(std::make_unique<doc::Code>());
-                return Error::success();
-            case doc::Kind::returns:
-                nodes.emplace_back(std::make_unique<doc::Returns>());
-                return Error::success();
-            case doc::Kind::param:
-                nodes.emplace_back(std::make_unique<doc::Param>());
-                return Error::success();
-            case doc::Kind::tparam:
-                nodes.emplace_back(std::make_unique<doc::TParam>());
-                return Error::success();
-            default:
-                return Error("invalid kind");
-            }
+            return visit(kind,
+                [&]<class T>()
+                {
+                    if constexpr(! std::is_same_v<T, void>)
+                    {
+                        nodes.emplace_back(std::make_unique<T>());
+                        return Error::success();
+                    }
+                    else
+                    {
+                        return Error("unknown doc::Kind");
+                    }
+                });
         }
         case JAVADOC_PARAM_DIRECTION:
         {
@@ -186,7 +164,7 @@ class JavadocNodesBlock
             auto node = nodes.back().get();
             if(node->kind != doc::Kind::styled)
                 return Error("style on wrong kind");
-            static_cast<doc::StyledText*>(
+            static_cast<doc::Styled*>(
                 node)->style = style;
             return Error::success();
 
diff --git a/source/AST/BitcodeWriter.cpp b/source/AST/BitcodeWriter.cpp
index 0e3243abe..177b688f1 100644
--- a/source/AST/BitcodeWriter.cpp
+++ b/source/AST/BitcodeWriter.cpp
@@ -853,78 +853,44 @@ emitBlock(
 {
     StreamSubBlockGuard Block(Stream, BI_JAVADOC_NODE_BLOCK_ID);
     emitRecord(I.kind, JAVADOC_NODE_KIND);
-    switch(I.kind)
-    {
-    case doc::Kind::text:
-    {
-        auto const& J = static_cast<doc::Text const&>(I);
-        emitRecord(J.string, JAVADOC_NODE_STRING);
-        break;
-    }
-    case doc::Kind::styled:
-    {
-        auto const& J = static_cast<doc::StyledText const&>(I);
-        emitRecord(J.style, JAVADOC_NODE_STYLE);
-        emitRecord(J.string, JAVADOC_NODE_STRING);
-        break;
-    }
-    case doc::Kind::heading:
-    {
-        auto const& J = static_cast<doc::Heading const&>(I);
-        emitRecord(J.string, JAVADOC_NODE_STRING);
-        break;
-    }
-    case doc::Kind::paragraph:
-    {
-        auto const& J = static_cast<doc::Paragraph const&>(I);
-        emitBlock(J.children);
-        break;
-    }
-    case doc::Kind::brief:
-    {
-        auto const& J = static_cast<doc::Brief const&>(I);
-        emitBlock(J.children);
-        break;
-    }
-    case doc::Kind::admonition:
-    {
-        auto const& J = static_cast<doc::Admonition const&>(I);
-        emitRecord(J.style, JAVADOC_NODE_ADMONISH);
-        emitBlock(J.children);
-        break;
-    }
-    case doc::Kind::code:
-    {
-        auto const& J = static_cast<doc::Code const&>(I);
-        emitBlock(J.children);
-        break;
-    }
-    case doc::Kind::returns:
-    {
-        auto const& J = static_cast<doc::Returns const&>(I);
-        emitBlock(J.children);
-        break;
-    }
-    case doc::Kind::param:
-    {
-        auto const& J = static_cast<doc::Param const&>(I);
-        emitRecord(J.direction, JAVADOC_PARAM_DIRECTION);
-        emitRecord(J.name, JAVADOC_NODE_STRING);
-        emitBlock(J.children);
-        break;
-    }
-    case doc::Kind::tparam:
-    {
-        auto const& J = static_cast<doc::TParam const&>(I);
-        emitRecord(J.name, JAVADOC_NODE_STRING);
-        emitBlock(J.children);
-        break;
-    }
-    default:
-        // unknown kind
-        MRDOX_UNREACHABLE();
-        break;
-    }
+    doc::visit(I.kind,
+        [&]<class T>()
+        {
+            if constexpr(! std::is_void_v<T>)
+            {
+                auto const& J = static_cast<T const&>(I);
+
+                if constexpr(
+                        std::derived_from<T, doc::Heading> ||
+                        std::derived_from<T, doc::Text>)
+                    emitRecord(J.string, JAVADOC_NODE_STRING);
+
+                if constexpr(std::derived_from<T, doc::Admonition>)
+                    emitRecord(J.style, JAVADOC_NODE_ADMONISH);
+
+                if constexpr(std::derived_from<T, doc::Styled>)
+                    emitRecord(J.style, JAVADOC_NODE_STYLE);
+
+                if constexpr(
+                        std::derived_from<T, doc::Param>)
+                {
+                    emitRecord(J.name, JAVADOC_NODE_STRING);
+                    emitRecord(J.direction, JAVADOC_PARAM_DIRECTION);
+                }
+
+                if constexpr(std::derived_from<T, doc::TParam>)
+                {
+                    emitRecord(J.name, JAVADOC_NODE_STRING);
+                }
+
+                if constexpr(std::derived_from<T, doc::Block>)
+                    emitBlock(J.children);
+            }
+            else
+            {
+                MRDOX_UNREACHABLE();
+            }
+        });
 }
 
 void
diff --git a/source/AST/ParseJavadoc.cpp b/source/AST/ParseJavadoc.cpp
index acea7b439..c439fb685 100644
--- a/source/AST/ParseJavadoc.cpp
+++ b/source/AST/ParseJavadoc.cpp
@@ -248,7 +248,7 @@ class JavadocVisitor
 
         if(style != doc::Style::none)
             Javadoc::append(*paragraph_, std::make_unique<
-                doc::StyledText>(std::move(s), style));
+                doc::Styled>(std::move(s), style));
         else
             Javadoc::append(*paragraph_, std::make_unique<
                 doc::Text>(std::move(s)));