EVIL tagged union hackjob

1 files changed, 102 insertions, 0 deletions

diff --git a/src/include/tagged_enum.hpp b/src/include/tagged_enum.hpp
new file mode 100644
index 00000000..07bd5881
--- /dev/null
+++ b/src/include/tagged_enum.hpp
@@ -0,0 +1,102 @@
+
+#define TE_DATANAME(name)   Data_##name
+#define ENUM_CONS(__tag, __type) \
+    static self_t make_##__tag(__type v) \
+    {\
+        self_t  ret;\
+        ret.m_tag = __tag;\
+        new (ret.m_data) __type( ::std::move(v) ); \
+        return ::std::move(ret); \
+    }\
+    bool is_##__tag() const { return m_tag == __tag; } \
+    const __type& as_##__tag() const { return reinterpret_cast<const __type&>(m_data); } \
+    __type& as_##__tag() { return reinterpret_cast<__type&>(m_data); } \
+    __type unwrap_##__tag() { return ::std::move(reinterpret_cast<__type&>(m_data)); } \
+
+#define TE_CONS(name, _) ENUM_CONS(name, TE_DATANAME(name))
+#define TE_CONS2(a, b)  TE_CONS a TE_CONS b
+#define TE_CONS3(a, ...)  TE_CONS a TE_CONS2(__VA_ARGS__)
+#define TE_CONS4(a, ...)  TE_CONS a TE_CONS3(__VA_ARGS__)
+#define TE_CONS5(a, ...)  TE_CONS a TE_CONS4(__VA_ARGS__)
+#define TE_CONS6(a, ...)  TE_CONS a TE_CONS5(__VA_ARGS__)
+
+// Sizes of structures
+#define TE_SO(name, _)   sizeof(TE_DATANAME(name))
+#define MAX2(a, b)  (a < b ? b : a)
+#define MAXS2(a, b)  (TE_SO a < TE_SO b ? TE_SO b : TE_SO a)
+#define MAXS3(a, b, c)   MAX2(MAXS2(a, b), TE_SO c)
+#define MAXS4(a, b, c, d)   MAX2(MAXS2(a, b), MAXS2(c, d))
+#define MAXS5(a, b, c, d, e)   MAX2(MAXS3(a, b, c), MAXS2(d, e))
+#define MAXS6(a, b, c, d, e, f)  MAX2(MAXS3(a, b, c), MAXS3(d, e, f))
+
+// Type definitions
+#define TE_EXP(...)  __VA_ARGS__
+#define TE_TYPEDEF(name, content)    struct TE_DATANAME(name) { TE_EXP content };
+#define TE_TYPEDEF2(_1, _2) TE_TYPEDEF _1 TE_TYPEDEF _2
+#define TE_TYPEDEF3(_1, ...) TE_TYPEDEF _1 TE_TYPEDEF2(__VA_ARGS__)
+#define TE_TYPEDEF4(_1, ...) TE_TYPEDEF _1 TE_TYPEDEF3(__VA_ARGS__)
+#define TE_TYPEDEF5(_1, ...) TE_TYPEDEF _1 TE_TYPEDEF4(__VA_ARGS__)
+#define TE_TYPEDEF6(_1, ...) TE_TYPEDEF _1 TE_TYPEDEF5(__VA_ARGS__)
+
+#define TE_TAG(name, _)  name,
+#define TE_TAG2(_1,_2)  TE_TAG _1 TE_TAG _2
+#define TE_TAG3(_1,...) TE_TAG _1 TE_TAG2(__VA_ARGS__)
+#define TE_TAG4(_1,...) TE_TAG _1 TE_TAG3(__VA_ARGS__)
+#define TE_TAG5(_1,...) TE_TAG _1 TE_TAG4(__VA_ARGS__)
+#define TE_TAG6(_1,...) TE_TAG _1 TE_TAG5(__VA_ARGS__)
+
+#define TE_DEST_CASE(tag, _)  case tag: as_##tag().~TE_DATANAME(tag)(); break;
+#define TE_DEST_CASE2(_1,_2)   TE_DEST_CASE _1 TE_DEST_CASE _2
+#define TE_DEST_CASE3(_1, ...) TE_DEST_CASE _1 TE_DEST_CASE2(__VA_ARGS__)
+#define TE_DEST_CASE4(_1, ...) TE_DEST_CASE _1 TE_DEST_CASE3(__VA_ARGS__)
+#define TE_DEST_CASE5(_1, ...) TE_DEST_CASE _1 TE_DEST_CASE4(__VA_ARGS__)
+#define TE_DEST_CASE6(_1, ...) TE_DEST_CASE _1 TE_DEST_CASE5(__VA_ARGS__)
+
+#define TE_MOVE_CASE(tag, _)  case tag: new(m_data) TE_DATANAME(tag)(x.unwrap_##tag()); break;
+#define TE_MOVE_CASE2(_1,_2)   TE_MOVE_CASE _1 TE_MOVE_CASE _2
+#define TE_MOVE_CASE3(_1, ...) TE_MOVE_CASE _1 TE_MOVE_CASE2(__VA_ARGS__)
+#define TE_MOVE_CASE4(_1, ...) TE_MOVE_CASE _1 TE_MOVE_CASE3(__VA_ARGS__)
+#define TE_MOVE_CASE5(_1, ...) TE_MOVE_CASE _1 TE_MOVE_CASE4(__VA_ARGS__)
+#define TE_MOVE_CASE6(_1, ...) TE_MOVE_CASE _1 TE_MOVE_CASE5(__VA_ARGS__)
+
+// Macro to obtain a numbered macro for argument counts
+#define TE_GM(SUF,_1,_2,_3,_4,_5,_6,COUNT,...) SUF##COUNT
+
+#define MAXS(...)          TE_GM(MAXS        ,__VA_ARGS__,6,5,4,3,2)(__VA_ARGS__)
+#define TE_TYPEDEFS(...)   TE_GM(TE_TYPEDEF  ,__VA_ARGS__,6,5,4,3,2)(__VA_ARGS__)
+#define TE_TAGS(...)       TE_GM(TE_TAG      ,__VA_ARGS__,6,5,4,3,2)(__VA_ARGS__)
+#define TE_DEST_CASES(...) TE_GM(TE_DEST_CASE,__VA_ARGS__,6,5,4,3,2)(__VA_ARGS__)
+#define TE_MOVE_CASES(...) TE_GM(TE_MOVE_CASE,__VA_ARGS__,6,5,4,3,2)(__VA_ARGS__)
+#define TE_CONSS(...)      TE_GM(TE_CONS     ,__VA_ARGS__,6,5,4,3,2)(__VA_ARGS__)
+
+#define TAGGED_ENUM(_name, _def, ...) \
+class _name { \
+    typedef _name self_t; \
+    TE_TYPEDEFS(__VA_ARGS__) \
+    enum Tag { \
+        TE_TAGS(__VA_ARGS__)\
+    } m_tag; \
+    char m_data[MAXS(__VA_ARGS__)]; \
+public:\
+    _name(): m_tag(_def) {}\
+    _name(_name&& x): m_tag(x.m_tag) { x.m_tag = _def; switch(m_tag) {  TE_MOVE_CASES(__VA_ARGS__) } } \
+    ~_name() { switch(m_tag) { TE_DEST_CASES(__VA_ARGS__) } } \
+    TE_CONSS(__VA_ARGS__) \
+}
+
+#define ENUM3(_name, _def, _t1, _v1, _t2, _v2, _t3, _v3)\
+    TAGGED_ENUM(_name, _def,\
+        (_t1, _v1), \
+        (_t2, _v2), \
+        (_t3, _v3) \
+        )
+
+/*
+    ENUM5(Inner, Any,
+        Any, bool,
+        Tuple, ::std::vector<Pattern>,
+        TupleStruct, struct { Path path; ::std::vector<Pattern> sub_patterns; },
+        Value, ::std::unique_ptr<ExprNode>,
+        Range, struct { ::std::unique_ptr<ExprNode> left; ::std::unique_ptr<ExprNode> right; }
+        )   m_contents;
+*/