feat: Changed function yield type prefix

closes #257

CHANGELOG.md

@@ -42,6 +42,7 @@ var value = from {
 - `File.readLine`, `File.readAll`, `Socket.readLine`, `Socket.readAll` have now an optional `maxSize` argument
 - Tail call optimization (https://github.com/buzz-language/buzz/issues/9). The effect should be limited for recursive calls since the JIT should kick in pretty quickly in those use cases.
 - Empty list and map without a specified type resolve to `[any]`/`{any: any}` unless the variable declaration context provides the type (https://github.com/buzz-language/buzz/issues/86)
+- Function yield type is now prefixed with `*>`: `fun willYield() > T > Y?` becomes `fun willYield() > T *> Y?` (https://github.com/buzz-language/buzz/issues/257)
 
 ## Fixed
 

examples/sqlite.buzz

@@ -141,7 +141,7 @@ export object Query {
         return db.prepare(this);
     }
 
-    fun execute(Database db) > [[Boxed]] > [Boxed]? !> SQLiteError {
+    fun execute(Database db) > [[Boxed]] *> [Boxed]? !> SQLiteError {
         return db.prepare(this).execute();
     }
 }
@@ -151,7 +151,7 @@ export object Statement {
     ud db,
     ud stmt,
 
-    fun execute() > [[Boxed]] > [Boxed]? !> SQLiteError {
+    fun execute() > [[Boxed]] *> [Boxed]? !> SQLiteError {
         Logger.instance?.debug("Executing query `{this.query}`", namespace: "SQL");
         ResultCode code = ResultCode.Ok;
 

src/Parser.zig

@@ -2666,10 +2666,11 @@ fn parseFunctionType(self: *Self, parent_generic_types: ?std.AutoArrayHashMap(*o
     else
         null;
 
-    const yield_type = if (try self.match(.Greater))
-        try self.parseTypeDef(null, true)
-    else
-        null;
+    var yield_type: ?Ast.Node.Index = null;
+    if (try self.match(.Star)) {
+        try self.consume(.Greater, "Expected `>` before yield type");
+        yield_type = try self.parseTypeDef(null, true);
+    }
 
     var error_types_list = std.ArrayList(Ast.Node.Index).init(self.gc.allocator);
     defer error_types_list.shrinkAndFree(error_types_list.items.len);
@@ -4887,7 +4888,9 @@ fn function(
     }
 
     // Parse yield type
-    const yield_type_node = if (return_type_node != null and function_type.canYield() and (try self.match(.Greater))) yield: {
+    const yield_type_node = if (return_type_node != null and function_type.canYield() and (try self.match(.Star))) yield: {
+        try self.consume(.Greater, "Expected `>` before yield type");
+
         const yield_type_node = try self.parseTypeDef(function_typedef.resolved_type.?.Function.generic_types, true);
         const yield_type = self.ast.nodes.items(.type_def)[yield_type_node].?;
 

src/lib/http.buzz

@@ -161,7 +161,7 @@ export object Client {
         };
     }
 
-    fun send(Request request) > Response > void !> HttpError, InvalidArgumentError, HttpParseError {
+    fun send(Request request) > Response *> void !> HttpError, InvalidArgumentError, HttpParseError {
         _ = this.start(request);
 
         yield void;

tests/038-fibers.buzz

@@ -21,7 +21,7 @@ test "fiber" {
 }
 
 | returns str, yields int
-fun count(int n) > str > int? {
+fun count(int n) > str *> int? {
     assert(currentFiber() is fib<str, int?>, message: "Can get current fiber");
     assert(!currentFiber().isMain(), message: "Can know if fiber is main one");
 

tests/041-iterator.buzz

@@ -1,6 +1,6 @@
 import "std";
 
-fun fibonnaci(int n) > void > int? {
+fun fibonnaci(int n) > void *> int? {
     int n1 = 0;
     int n2 = 1;
     int? next = null;
@@ -24,7 +24,7 @@ test "finobacci generator" {
 }
 
 object Hello {
-    fun range() > [int] > int? {
+    fun range() > [int] *> int? {
         var list = [<int>];
         foreach (int i in 0..10) {
             _ = yield i;

tests/048-generics.buzz

@@ -65,7 +65,7 @@ test "generic return" {
     assert(genericReturn::<int>(12) == 12, message: "could use return of generic type");
 }
 
-fun fiber::<T>([T] data) > void > T? {
+fun fiber::<T>([T] data) > void *> T? {
     foreach (T element in data) {
         _ = yield element;
     }

tests/059-types-as-value.buzz

@@ -29,7 +29,7 @@ test "typeof" {
     assert(typeof 1 == <int>, message: "typeof operator int");
     assert(typeof 3.14 == <float>, message: "typeof operator float");
     assert(typeof $"hello" == <pat>, message: "typeof operator pattern");
-    assert(typeof dumpType == <Function(type myType) > void > void>, message: "typeof operator");
+    assert(typeof dumpType == <Function(type myType) > void *> void>, message: "typeof operator");
 }
 
 test "type argument" {

tests/compile_errors/006-deep-yield.buzz

@@ -1,7 +1,7 @@
 | Bad function yield type
 import "std";
 
-fun one() > void > str? {
+fun one() > void *> str? {
     yield "hello";
 }
 

tests/compile_errors/021-fiber-error-location.buzz

@@ -1,7 +1,7 @@
 | :7:13
 import "std";
 
-fun count(int n) > str > int? {
+fun count(int n) > str *> int? {
     for (int i = 0; i < n; i = i + 1) {
     	if (i == 2) {
             throw "an error occured";