Allow bare zero-arg yield across newlines

Author: mgomes

examples/blocks/yield_patterns.vibe

@@ -22,7 +22,7 @@ end
 
 def benchmark
   start = Time.now
-  result = yield()
+  result = yield
   elapsed = Time.now - start
   { result: result, elapsed: elapsed }
 end

vibes/parser_yield_literals.go

@@ -17,7 +17,7 @@ func (p *parser) parseYieldExpression() Expression {
 				return nil
 			}
 		}
-	} else if p.prefixFns[p.peekToken.Type] != nil {
+	} else if p.peekToken.Pos.Line == pos.Line && p.prefixFns[p.peekToken.Type] != nil {
 		p.nextToken()
 		args = append(args, p.parseExpression(lowestPrec))
 	}

vibes/parser_yield_test.go

@@ -0,0 +1,80 @@
+package vibes
+
+import "testing"
+
+func TestParserYieldWithoutParensDoesNotConsumeNextLineInAssignment(t *testing.T) {
+	source := `def run
+  result = yield
+  elapsed = 1
+end`
+
+	p := newParser(source)
+	program, errs := p.ParseProgram()
+	if len(errs) > 0 {
+		t.Fatalf("expected no parse errors, got %v", errs)
+	}
+	if len(program.Statements) != 1 {
+		t.Fatalf("expected 1 statement, got %d", len(program.Statements))
+	}
+
+	fn, ok := program.Statements[0].(*FunctionStmt)
+	if !ok {
+		t.Fatalf("expected function statement, got %T", program.Statements[0])
+	}
+	if len(fn.Body) != 2 {
+		t.Fatalf("expected 2 body statements, got %d", len(fn.Body))
+	}
+
+	first, ok := fn.Body[0].(*AssignStmt)
+	if !ok {
+		t.Fatalf("expected first statement assignment, got %T", fn.Body[0])
+	}
+	yieldExpr, ok := first.Value.(*YieldExpr)
+	if !ok {
+		t.Fatalf("expected yield expression, got %T", first.Value)
+	}
+	if len(yieldExpr.Args) != 0 {
+		t.Fatalf("expected zero-arg yield, got %d args", len(yieldExpr.Args))
+	}
+
+	second, ok := fn.Body[1].(*AssignStmt)
+	if !ok {
+		t.Fatalf("expected second statement assignment, got %T", fn.Body[1])
+	}
+	target, ok := second.Target.(*Identifier)
+	if !ok || target.Name != "elapsed" {
+		t.Fatalf("expected second assignment to elapsed, got %#v", second.Target)
+	}
+}
+
+func TestParserYieldWithoutParensAcceptsInlineArgument(t *testing.T) {
+	source := `def run
+  result = yield value
+end`
+
+	p := newParser(source)
+	program, errs := p.ParseProgram()
+	if len(errs) > 0 {
+		t.Fatalf("expected no parse errors, got %v", errs)
+	}
+
+	fn, ok := program.Statements[0].(*FunctionStmt)
+	if !ok {
+		t.Fatalf("expected function statement, got %T", program.Statements[0])
+	}
+	assign, ok := fn.Body[0].(*AssignStmt)
+	if !ok {
+		t.Fatalf("expected assignment, got %T", fn.Body[0])
+	}
+	yieldExpr, ok := assign.Value.(*YieldExpr)
+	if !ok {
+		t.Fatalf("expected yield expression, got %T", assign.Value)
+	}
+	if len(yieldExpr.Args) != 1 {
+		t.Fatalf("expected one yield arg, got %d", len(yieldExpr.Args))
+	}
+	arg, ok := yieldExpr.Args[0].(*Identifier)
+	if !ok || arg.Name != "value" {
+		t.Fatalf("expected yield arg value, got %#v", yieldExpr.Args[0])
+	}
+}