A decent union type with common fields and variants

2 files changed, 69 insertions, 78 deletions

diff --git a/core/_preload.odin b/core/_preload.odin
index c61049290..c1014fa95 100644
--- a/core/_preload.odin
+++ b/core/_preload.odin
@@ -14,22 +14,11 @@
 
 // IMPORTANT NOTE(bill): Do not change the order of any of this data
 // The compiler relies upon this _exact_ order
-Type_Info_Record :: struct #ordered {
-	types:        []^Type_Info,
-	names:        []string,
-	offsets:      []int,    // offsets may not be used in tuples
-	size:         int, // in bytes
-	align:        int, // in bytes
-	packed:       bool,
-	ordered:      bool,
-	custom_align: bool,
-}
 Type_Info_Enum_Value :: raw_union {
 	f: f64,
 	i: i64,
 }
-
-// NOTE(bill): This much the same as the compiler's
+// NOTE(bill): This must match the compiler's
 Calling_Convention :: enum {
 	ODIN = 0,
 	C    = 1,
@@ -37,67 +26,17 @@ Calling_Convention :: enum {
 	FAST = 3,
 }
 
-/*
-Type_Info :: union {
-	Named: struct #ordered {
-		name: string,
-		base: ^Type_Info, // This will _not_ be a Type_Info.Named
-	},
-	Integer: struct #ordered {
-		size:   int, // in bytes
-		signed: bool,
-	},
-	Float: struct #ordered {
-		size: int, // in bytes
-	},
-	String:  struct #ordered {},
-	Boolean: struct #ordered {},
-	Any:     struct #ordered {},
-	Pointer: struct #ordered {
-		elem: ^Type_Info, // nil -> rawptr
-	},
-	Procedure: struct #ordered {
-		params:     ^Type_Info, // Type_Info.Tuple
-		results:    ^Type_Info, // Type_Info.Tuple
-		variadic:   bool,
-		convention: Calling_Convention,
-	},
-	Array: struct #ordered {
-		elem:      ^Type_Info,
-		elem_size: int,
-		count:     int,
-	},
-	Dynamic_Array: struct #ordered {
-		elem:      ^Type_Info,
-		elem_size: int,
-	},
-	Slice: struct #ordered {
-		elem:      ^Type_Info,
-		elem_size: int,
-	},
-	Vector: struct #ordered {
-		elem:      ^Type_Info,
-		elem_size: int,
-		count:     int,
-		align:     int,
-	},
-	Tuple:     Type_Info_Record, // Only really used for procedures
-	Struct:    Type_Info_Record,
-	Union:     Type_Info_Record,
-	Raw_Union: Type_Info_Record,
-	Enum: struct #ordered {
-		base:   ^Type_Info,
-		names:  []string,
-		values: []Type_Info_Enum_Value,
-	},
-	Map: struct #ordered {
-		key:              ^Type_Info,
-		value:            ^Type_Info,
-		generated_struct: ^Type_Info,
-		count:            int, // == 0 if dynamic
-	},
+Type_Info_Record :: struct #ordered {
+	types:        []^Type_Info,
+	names:        []string,
+	offsets:      []int,    // offsets may not be used in tuples
+	size:         int, // in bytes
+	align:        int, // in bytes
+	packed:       bool,
+	ordered:      bool,
+	custom_align: bool,
 }
-*/
+
 Type_Info :: union {
 	Named{name: string, base: ^Type_Info},
 	Integer{size: int, signed: bool},
@@ -124,8 +63,18 @@ Type_Info :: union {
 	Vector       {elem: ^Type_Info, elem_size, count, align: int},
 	Tuple        {using record: Type_Info_Record}, // Only really used for procedures
 	Struct       {using record: Type_Info_Record},
-	Union        {using record: Type_Info_Record},
 	Raw_Union    {using record: Type_Info_Record},
+	Union{
+		common_fields: struct {
+			types:        []^Type_Info,
+			names:        []string,
+			offsets:      []int,    // offsets may not be used in tuples
+		},
+		variant_names: []string,
+		variant_types: []^Type_Info,
+		size:          int,
+		align:         int,
+	},
 	Enum{
 		base:   ^Type_Info,
 		names:  []string,
@@ -142,7 +91,7 @@ Type_Info :: union {
 
 // // NOTE(bill): only the ones that are needed (not all types)
 // // This will be set by the compiler
-// immutable __type_infos: []Type_Info;
+__type_infos: []Type_Info;
 
 type_info_base :: proc(info: ^Type_Info) -> ^Type_Info {
 	if info == nil {
diff --git a/core/fmt.odin b/core/fmt.odin
index d340bbe5d..54fbfa7f3 100644
--- a/core/fmt.odin
+++ b/core/fmt.odin
@@ -215,11 +215,36 @@ buffer_write_type :: proc(buf: ^Buffer, ti: ^Type_Info) {
 
 	case Union:
 		buffer_write_string(buf, "union {");
-		for name, i in info.names {
+		cf := info.common_fields;
+		total_count := 0;
+		for name, i in cf.names {
+			if i > 0 {
+				buffer_write_string(buf, ", ");
+			}
 			buffer_write_string(buf, name);
 			buffer_write_string(buf, ": ");
-			buffer_write_type(buf, info.types[i]);
-			buffer_write_byte(buf, ',');
+			buffer_write_type(buf, cf.types[i]);
+			total_count += 1;
+		}
+		for name, i in info.variant_names {
+			if i > 0 || total_count > 0 {
+				buffer_write_string(buf, ", ");
+			}
+			buffer_write_string(buf, name);
+			buffer_write_byte(buf, '{');
+			defer buffer_write_byte(buf, '}');
+
+			variant_type := type_info_base(info.variant_types[i]);
+			variant := union_cast(^Struct)variant_type;
+
+			for j in cf.names.count..<variant.names.count {
+				if j > 0 {
+					buffer_write_byte(buf, ',');
+				}
+				buffer_write_string(buf, variant.names[j]);
+				buffer_write_string(buf, ": ");
+				buffer_write_type(buf, variant.types[j]);
+			}
 		}
 		buffer_write_string(buf, "}");
 
@@ -687,6 +712,9 @@ fmt_enum :: proc(fi: ^Fmt_Info, v: any, verb: rune) {
 						break;
 					}
 				}
+			} else if e.values.count == 0 {
+				buffer_write_string(fi.buf, "");
+				ok = true;
 			} else {
 				for it, idx in e.values {
 					if it.f == f {
@@ -864,7 +892,21 @@ fmt_value :: proc(fi: ^Fmt_Info, v: any, verb: rune) {
 		}
 
 	case Union:
-		buffer_write_string(fi.buf, "(union)");
+		buffer_write_byte(fi.buf, '{');
+		defer buffer_write_byte(fi.buf, '}');
+
+		cf := info.common_fields;
+
+		for _, i in cf.names {
+			if i > 0 {
+				buffer_write_string(fi.buf, ", ");
+			}
+			buffer_write_string(fi.buf, cf.names[i]);
+			buffer_write_string(fi.buf, " = ");
+			data := cast(^byte)v.data + cf.offsets[i];
+			fmt_value(fi, any{cf.types[i], cast(rawptr)data}, 'v');
+		}
+
 	case Raw_Union:
 		buffer_write_string(fi.buf, "(raw_union)");