comptime expandable match statements

examples/programs/expand/main.bro

@@ -0,0 +1,94 @@
+Kind :: enum {
+	first
+	second
+	third
+}
+
+Pair :: struct {
+	left i32
+	right i32
+}
+
+Value :: union(enum) {
+	number i32
+	pair Pair
+	empty void
+}
+
+enum_score func(kind Kind) i32 {
+	result :: match kind {
+		.first: 1
+		expand |value|: {
+			yield match value {
+				.second: 2
+				.third:  3
+			}
+		}
+	}
+	return result
+}
+
+equal_value func(a, b Value) bool {
+	if (tag!(a) != tag!(b)) return false
+	result :: match a {
+		expand |value, tag|: {
+			yield match tag {
+				.number: value == field!(b, tagname!(tag))
+				.pair: {
+					other :: field!(b, tagname!(tag))
+					yield value.left == other.left and value.right == other.right
+				}
+				.empty: {
+					yield true
+				}
+			}
+		}
+	}
+	return result
+}
+
+increment func(value @mut Value) void {
+	match value^ {
+		expand |@payload, tag|: match tag {
+			.number: payload^ += 1
+			.pair:   payload.left += 1
+			.empty:  _ = payload
+		}
+	}
+}
+
+main func() i32 {
+	if enum_score(.first) != 1 or enum_score(.second) != 2 or enum_score(.third) != 3 {
+		return 1
+	}
+
+	known :: $tag!(Value{number = 1})
+	known_direct :: tag!(Value{pair = Pair{left = 0, right = 0}})
+	if (known != .number) or (known_direct != .pair) {
+		return 2
+	}
+
+	a Value = .number{41}
+	b Value = .number{41}
+	if !equal_value(a, b) or equal_value(a, .pair{left = 41, right = 0}) {
+		return 3
+	}
+	increment(&a)
+	if a.number != 42 {
+		return 4
+	}
+
+	pair_a Value = .pair{left = 2, right = 3}
+	pair_b Value = .pair{left = 2, right = 3}
+	if !equal_value(pair_a, pair_b) or !equal_value(.empty, .empty) {
+		return 5
+	}
+	increment(&pair_a)
+	if pair_a.pair.left != 3 {
+		return 6
+	}
+
+	empty Value = .empty
+	increment(&empty)
+	return 0
+}

examples/programs/tuples/main.bro

@@ -11,7 +11,7 @@ format func() []u8 {
 sum func($T type, value T) i32 {
 	total i32 = 0
 	match typeinfo!(T) {
-		.record |record|: inline for record.fields |field| {
+		.record |record|: expand for record.fields |field| {
 			total += i32(field!(value, field.name))
 		}
 		else: compile_error!("sum requires a record")
@@ -22,7 +22,7 @@ sum func($T type, value T) i32 {
 static_control func($T type, value T) i32 {
 	total i32 = 0
 	match typeinfo!(T) {
-		.record |record|: inline for record.fields |field| {
+		.record |record|: expand for record.fields |field| {
 			{
 				if field.index == 1 {
 					continue
@@ -50,7 +50,7 @@ row_value func(row Row) i32 {
 
 static_aggregates func() i32 {
 	total i32 = 0
-	inline for {Row {value = 2}, Row {value = 40}} |row| {
+	expand for {Row {value = 2}, Row {value = 40}} |row| {
 		total += row_value(row)
 	}
 	return total