From e92e98805c1bc2389c21739e997bae1585e2a119 Mon Sep 17 00:00:00 2001
From: Vinnie Falco <vinnie.falco@gmail.com>
Date: Mon, 3 Jul 2023 08:30:02 -0700
Subject: [PATCH] feat: Array::emplace_back

---
 include/mrdox/Support/Dom.hpp | 52 ++++++++++++++++++++++
 source/Support/Dom.cpp        | 84 ++++++++++++++++++++++-------------
 2 files changed, 105 insertions(+), 31 deletions(-)

diff --git a/include/mrdox/Support/Dom.hpp b/include/mrdox/Support/Dom.hpp
index d35c7efc1..bbd15cac7 100644
--- a/include/mrdox/Support/Dom.hpp
+++ b/include/mrdox/Support/Dom.hpp
@@ -124,6 +124,13 @@ class MRDOX_DECL
     */
     value_type at(size_type i) const;
 
+    /** Append an element to the end of the array.
+
+        If the array is read-only, an exception
+        is thrown.
+    */
+    void emplace_back(value_type value);
+
     /** Return a diagnostic string.
     */
     friend
@@ -162,6 +169,46 @@ class MRDOX_DECL
     /** Return the i-th element, without bounds checking.
     */
     virtual value_type get(size_type i) const = 0;
+
+    /** Append an element to the end of the array.
+
+        The default implementation throws an exception,
+        making the array effectively read-only.
+    */
+    virtual void emplace_back(value_type value);
+};
+
+//------------------------------------------------
+//
+// DefaultArrayImpl
+//
+//------------------------------------------------
+
+/** The default array implementation.
+
+    This implementation is backed by a simple
+    vector and allows appending.
+*/
+class MRDOX_DECL
+    DefaultArrayImpl : public ArrayImpl
+{
+public:
+    /// @copydoc Array::value_type
+    using value_type = Array::value_type;
+
+    /// @copydoc Array::size_type
+    using size_type = Array::size_type;
+
+    /** The type of storage used by the default implementation.
+    */
+    using storage_type = std::vector<value_type>;
+
+    size_type size() const override;
+    value_type get(size_type i) const override;
+    void emplace_back(value_type value) override;
+
+private:
+    std::vector<value_type> elements_;
 };
 
 /** Return a new array using a custom implementation.
@@ -923,6 +970,11 @@ inline auto Array::at(std::size_t i) const -> value_type
     Error("out of range").Throw();
 }
 
+inline void Array::emplace_back(value_type value)
+{
+    impl_->emplace_back(std::move(value));
+}
+
 //------------------------------------------------
 
 inline bool Object::empty() const
diff --git a/source/Support/Dom.cpp b/source/Support/Dom.cpp
index 9ab859ad9..0018fb5d8 100644
--- a/source/Support/Dom.cpp
+++ b/source/Support/Dom.cpp
@@ -27,34 +27,6 @@ static_assert(std::ranges::random_access_range<Object>);
 //
 //------------------------------------------------
 
-namespace {
-
-class DefaultArrayImpl : public ArrayImpl
-{
-    std::vector<Value> v_;
-
-public:
-    std::size_t
-    size() const noexcept override
-    {
-        return v_.size();
-    }
-
-    Value get(std::size_t i) const override
-    {
-        MRDOX_ASSERT(i < v_.size());
-        return v_[i];
-    }
-};
-
-} // (anon)
-
-//------------------------------------------------
-//
-// Array
-//
-//------------------------------------------------
-
 Array::
 ~Array() = default;
 
@@ -97,19 +69,60 @@ toString(
     return s;
 }
 
+//------------------------------------------------
+//
+// ArrayImpl
+//
 //------------------------------------------------
 
 ArrayImpl::
 ~ArrayImpl() = default;
 
+void
+ArrayImpl::
+emplace_back(
+    value_type value)
+{
+    Error("Array is const").Throw();
+}
+
 //------------------------------------------------
 //
-// Object
+// DefaultArrayImpl
 //
 //------------------------------------------------
 
-ObjectImpl::
-~ObjectImpl() = default;
+auto
+DefaultArrayImpl::
+size() const ->
+    size_type
+{
+    return elements_.size();
+}
+
+auto
+DefaultArrayImpl::
+get(
+    size_type i) const ->
+        value_type
+{
+    MRDOX_ASSERT(i < elements_.size());
+    return elements_[i];
+}
+
+void
+DefaultArrayImpl::
+emplace_back(
+    value_type value)
+{
+    elements_.emplace_back(std::move(value));
+}
+
+//------------------------------------------------
+//
+// Object
+//
+//------------------------------------------------
 
 Object::
 ~Object() = default;
@@ -169,6 +182,15 @@ toString(
     return s;
 }
 
+//------------------------------------------------
+//
+// ObjectImpl
+//
+//------------------------------------------------
+
+ObjectImpl::
+~ObjectImpl() = default;
+
 //------------------------------------------------
 //
 // DefaultObjectImpl