add mir.variant and mir.rc (#224)

Author: 9il

doc/Makefile

@@ -36,10 +36,11 @@ PACKAGE_mir = \
 	small_string \
 	small_array \
 	polynomial \
-	format\
-	parse\
-	appender\
-	exception\
+	format \
+	parse \
+	appender \
+	exception \
+	variant \
 
 PACKAGE_mir_algorithm = iteration setops
 PACKAGE_mir_array = allocation

index.d

@@ -23,6 +23,7 @@ $(BOOKTABLE ,
     $(TR $(TDNW $(MREF mir,math,constant)) $(TD Math constants))
     $(TR $(TDNW $(MREF mir,polynomial)) $(TD Polynomial ref-counted structure))
     $(LEADINGROW Reference counting)
+    $(TR $(TDNW $(MREF mir,rc)) $(TD Reference counting package and RC conversion utilities.))
     $(TR $(TDNW $(MREF mir,rc,array)) $(TD Thread safe reference count array and the iterator to adopt it to ndslice.))
     $(TR $(TDNW $(MREF mir,rc,ptr)) $(TD Thread safe reference count pointer with polymorphism support for strucs and objects.))
     $(TR $(TDNW $(MREF mir,rc,slim_ptr)) $(TD Thread safe reference count pointer for strucs and objects.))
@@ -40,6 +41,7 @@ $(BOOKTABLE ,
     $(LEADINGROW Interconnection with other languages)
     $(TR $(TDNW $(MREF mir,ndslice,connect,cpython)) $(TD Utilities for $(HTTPS docs.python.org/3/c-api/buffer.html, Python Buffer Protocol)))
     $(LEADINGROW Accessories)
+    $(TR $(TDNW $(MREF mir,variant)) $(TD Variant Type (aka Algebraic Type) with clever member access))
     $(TR $(TDNW $(MREF mir,exception)) $(TD @nogc MirException with formatting))
     $(TR $(TDNW $(MREF mir,format)) $(TD @nogc Formatting Utilities))
     $(TR $(TDNW $(MREF mir,parse)) $(TD @nogc Parsing Utilities))

meson.build

@@ -67,6 +67,7 @@ mir_algorithm_src = [
     'source/mir/small_array.d',
     'source/mir/small_string.d',
     'source/mir/type_info.d',
+    'source/mir/variant.d',
 ]
 
 mir_algorithm_lib = library(meson.project_name(),

source/mir/rc/array.d

@@ -9,12 +9,12 @@ import mir.rc.context;
 import mir.type_info;
 import std.traits;
 
-private static immutable allocationExcMsg = "mir_rcarray: out of memory error.";
+package static immutable allocationExcMsg = "mir_rcarray: out of memory error.";
 
 version (D_Exceptions)
 {
     import core.exception: OutOfMemoryError;
-    private static immutable allocationError = new OutOfMemoryError(allocationExcMsg);
+    package static immutable allocationError = new OutOfMemoryError(allocationExcMsg);
 }
 
 /++
@@ -27,16 +27,16 @@ The implementation never adds roots into the GC.
 struct mir_rcarray(T)
 {
     ///
-    private T* _payload;
-    private ref inout(mir_rc_context) context() inout scope return pure nothrow @nogc @trusted @property
+    package T* _payload;
+    package ref inout(mir_rc_context) context() inout scope return pure nothrow @nogc @trusted @property
     {
         assert(_payload);
         return (cast(inout(mir_rc_context)*)_payload)[-1];
     }
-    private void _reset() { _payload = null; }
+    package void _reset() { _payload = null; }
 
-    private alias ThisTemplate = .mir_rcarray;
-    private alias _thisPtr = _payload;
+    package alias ThisTemplate = .mir_rcarray;
+    package alias _thisPtr = _payload;
 
     ///
     void proxySwap(ref typeof(this) rhs) pure nothrow @nogc @safe
@@ -176,11 +176,11 @@ struct mir_rcarray(T)
 
     static if (isImplicitlyConvertible!(const T, T))
         static if (isImplicitlyConvertible!(const Unqual!T, T))
-            private alias V = const Unqual!T;
+            package alias V = const Unqual!T;
         else
-            private alias V = const T;
+            package alias V = const T;
     else
-        private alias V = T;
+        package alias V = T;
 
 }
 
@@ -215,7 +215,7 @@ unittest
     static assert(is(typeof(fs) == Slice!(double*)));
 }
 
-private template LikeArray(Range)
+package template LikeArray(Range)
 {
     static if (__traits(identifier, Range) == "mir_slice")
     {

source/mir/rc/package.d

@@ -1,10 +1,153 @@
 /++
 $(H1 Thread-safe reference-counted arrays and pointers)
 
-Publicly imports $(MREF mir,rc,array) and $(MREF mir,rc,ptr).
+Mir provides two kinds of ref-counting pointers and two kinds of ref-counted arrays.
+
+The first kind pointer is `RCPtr`, which consists of a pointer to the context and pointer to the value.`RCPtr` supports structural and object polymorphism. It allows getting members with the same context as the root.
+The second kind is `SlimRCPtr`, which consist only from a pointer to the value. The context for `SlimRCPtr`is computed using a fixed-length memory shift from the pointer to the value.
+`SlimRCPtr` can be converted to an `RCPtr` and to an `RCArray` of the one element.
+
+`RCArray` is an array type without range primitives. It's length can't be reduced after construction.In the other hand, `Slice!(RCI!(T))` is an ndslice with all random-access range primitives.`RCI` is an iterator, which consists of `RCArray` and the pointer to the current element.
+`RCArray!T` can be converted or moved to `Slice!(RCI!(T))` using `.asSlice` or `.moveToSlice` methods respectively.
+
+$(RED `RCArray!T` aliases itself to a common D array slice. This feature may cause a segmentation fault in safe code if used without DIP1000.)
+
+`RCPtr!T` can be constructed from an element index and `RCArray!T` / `Slice!(RCI!(T))`.
+
+The package publicly imports $(MREF mir,rc,array), $(MREF mir,rc,ptr), and $(MREF mir,rc,slim_ptr).
+
+See_also: $(MREF mir,ndslice).
 +/
 module mir.rc;
 
 public import mir.rc.array;
 public import mir.rc.ptr;
 public import mir.rc.slim_ptr;
+
+import mir.ndslice.slice;
+
+/++
+Returns: shared pointer constructed from the slim shared pointer.
+
+The function has zero computation cost.
++/
+RCPtr!F toRCPtr(F)(return SlimRCPtr!F contextAndValue) @trusted
+{
+    typeof(return) ret;
+    ret._value = contextAndValue._value;
+    ret._context = &contextAndValue.context();
+    contextAndValue._value = null;
+    return ret;
+}
+
+///
+version(mir_test)
+@safe pure @nogc nothrow
+unittest
+{
+    import core.lifetime: move;
+    struct S
+    {
+        double e;
+    }
+    struct C
+    {
+        int i;
+        S s;
+    }
+
+    auto a = createSlimRC!C(10, S(3));
+    auto s = a.move.toRCPtr.shareMember!"s";
+    assert(s._counter == 1);
+    assert(s.e == 3);
+}
+
+/++
+Returns: shared pointer constructed with the `array`'s context and the value points to `array[index]`.
+
+The function has zero computation cost.
++/
+RCPtr!F toRCPtrAt(F)(return RCArray!F array, size_t index) @trusted
+    if (!is(R == class) && !is(R == interface))
+in {
+    assert(index < array.length, "toRCPtrAt: index should be less then array.length");
+}
+body {
+    typeof(return) ret;
+    ret._value = array._payload + index;
+    ret._context = &array.context();
+    array._payload = null;
+    return ret;
+}
+
+///
+version(mir_test)
+@safe pure @nogc nothrow
+unittest
+{
+    struct S { double e; }
+
+    auto a = RCArray!S(10);
+    a[3].e = 4;
+
+    auto s = a.toRCPtrAt(3);
+
+    assert(s._counter == 2);
+    assert(s.e == 4);
+}
+
+/// ditto
+RCPtr!F toRCPtrAt(F)(return Slice!(RCI!F) array, size_t index) @trusted
+    if (!is(R == class) && !is(R == interface))
+in {
+    assert(index < array.length, "toRCPtrAt: index should be less then array.length");
+}
+body {
+    typeof(return) ret;
+    ret._value = array._iterator._iterator + index;
+    ret._context = &array._iterator._array.context();
+    array._iterator._array._payload = null;
+    return ret;
+}
+
+///
+version(mir_test)
+@safe pure @nogc nothrow
+unittest
+{
+    struct S { double e; }
+
+    auto a = RCArray!S(10).asSlice[5 .. $];
+    a[3].e = 4;
+
+    auto s = a.toRCPtrAt(3);
+
+    assert(s._counter == 2);
+    assert(s.e == 4);
+}
+
+/++
+Returns: RC array length of one constructed from the slim shared pointer.
+
+The function has zero computation cost.
++/
+RCArray!F toRCArray(F)(return SlimRCPtr!F context) @trusted
+{
+    typeof(return) ret;
+    ret._payload = context._value;
+    context._value = null;
+    return ret;
+}
+
+///
+version(mir_test)
+@safe pure @nogc nothrow
+unittest
+{
+    struct S { double e; }
+
+    auto a = createSlimRC!S(4).toRCArray;
+    assert(a._counter == 1);
+    assert(a.length == 1);
+    assert(a[0].e == 4);
+}

source/mir/rc/ptr.d

@@ -9,13 +9,13 @@ import mir.rc.context;
 import mir.type_info;
 import std.traits;
 
-private static immutable allocationExcMsg = "mir_rcptr: out of memory error.";
-private static immutable getExcMsg = "mir_rcptr: trying to use null value.";
+package static immutable allocationExcMsg = "mir_rcptr: out of memory error.";
+package static immutable getExcMsg = "mir_rcptr: trying to use null value.";
 
 version (D_Exceptions)
 {
     import core.exception: OutOfMemoryError, InvalidMemoryOperationError;
-    private static immutable allocationError = new OutOfMemoryError(allocationExcMsg);
+    package static immutable allocationError = new OutOfMemoryError(allocationExcMsg);
 }
 
 /++
@@ -34,17 +34,17 @@ struct mir_rcptr(T)
 
     ///
     static if (is(T == class) || is(T == interface))
-        private Unqual!T _value;
+        package Unqual!T _value;
     else
-        private T* _value;
-    private mir_rc_context* _context;
+        package T* _value;
+    package mir_rc_context* _context;
 
-    private ref inout(mir_rc_context) context() inout scope return @trusted @property
+    package ref inout(mir_rc_context) context() inout scope return @trusted @property
     {
         return *_context;
     }
 
-    private void _reset()
+    package void _reset()
     {
         _value = null;
         _context = null;
@@ -55,7 +55,7 @@ struct mir_rcptr(T)
         return cast(inout(void)*) _value;
     }
 
-    private alias ThisTemplate = .mir_rcptr;
+    package alias ThisTemplate = .mir_rcptr;
 
     /// ditto
     alias opUnary(string op : "*") = _get_value;
@@ -122,7 +122,7 @@ struct mir_rcptr(T)
 
     static if (!is(T == interface) && !__traits(isAbstractClass, T))
     {
-        private this(Args...)(auto ref Args args)
+        package this(Args...)(auto ref Args args)
         {
             () @trusted {
                 _context = mir_rc_create(mir_get_type_info!T, 1, mir_get_payload_ptr!T);
@@ -146,28 +146,30 @@ struct mir_rcptr(T)
 alias RCPtr = mir_rcptr;
 
 /++
+Returns: shared pointer of the member and the context from the current pointer. 
 +/
 auto shareMember(string member, T, Args...)(return mir_rcptr!T context, auto ref Args args)
 {
+    import core.lifetime: move;
     void foo(A)(auto ref A) {}
     static if (args.length)
     {
         // breaks safaty
         if (false) foo(__traits(getMember, context._get_value, member)(forward!args));
-        return (()@trusted => createRCWithContext(context, __traits(getMember, context._get_value, member)(forward!args)))();
+        return (()@trusted => createRCWithContext(__traits(getMember, context._get_value, member)(forward!args), context.move))();
     }
     else
     {
         // breaks safaty
         if (false) foo(__traits(getMember, context._get_value, member));
-        return (()@trusted => createRCWithContext(context, __traits(getMember, context._get_value, member)))();
+        return (()@trusted => createRCWithContext(__traits(getMember, context._get_value, member), context.move))();
     }
 }
 
 /++
 Returns: shared pointer constructed with current context. 
 +/
-@system .mir_rcptr!R createRCWithContext(R, F)(return const mir_rcptr!F context, return R value)
+@system .mir_rcptr!R createRCWithContext(R, F)(return R value, return const mir_rcptr!F context)
     if (is(R == class) || is(R == interface))
 {
     typeof(return) ret;
@@ -179,7 +181,7 @@ Returns: shared pointer constructed with current context.
 }
 
 ///ditto
-@system .mir_rcptr!R createRCWithContext(R, F)(return const mir_rcptr!F context, return ref R value)
+@system .mir_rcptr!R createRCWithContext(R, F)(return ref R value, return const mir_rcptr!F context)
     if (!is(R == class) && !is(R == interface))
 {
     typeof(return) ret;
@@ -197,21 +199,24 @@ Provides polymorphism abilities for classes and structures with `alias this` syn
 mir_rcptr!R castTo(R, T)(return mir_rcptr!T context) @trusted
     if (isImplicitlyConvertible!(T, R))
 {
-    return createRCWithContext(context, cast(R)context._get_value);
+    import core.lifetime: move;
+    return createRCWithContext(cast(R)context._get_value, move(context));
 }
 
 /// ditto
-mir_rcptr!(const R) castTo(R, T)(return const mir_rcptr!T context) @trusted const
+mir_rcptr!(const R) castTo(R, T)(return const mir_rcptr!T context) @trusted
     if (isImplicitlyConvertible!(const T, const R))
 {
-    return createRCWithContext(*cast(mir_rcptr!T*)&context, cast(const R)context._get_value);
+    import core.lifetime: move;
+    return createRCWithContext(cast(const R)context._get_value, move(*cast(mir_rcptr!T*)&context));
 }
 
 /// ditto
-mir_rcptr!(immutable R) castTo(R, T)(return immutable mir_rcptr!T context) @trusted immutable
+mir_rcptr!(immutable R) castTo(R, T)(return immutable mir_rcptr!T context) @trusted
     if (isImplicitlyConvertible!(immutable T, immutable R))
 {
-    return createRCWithContext(*cast(mir_rcptr!T*)&context, cast(immutable R)context._get_value);
+    import core.lifetime: move;
+    return createRCWithContext(cast(immutable R)context._get_value, move(*cast(mir_rcptr!T*)&context));
 }
 
 
@@ -302,7 +307,7 @@ unittest
 
 version(unittest):
 
-private struct _test_unpure_system_dest_s__ {
+package struct _test_unpure_system_dest_s__ {
     static int numStructs;
     int i;