Add syntactic sugar for fn::open

ast/environment_test.go

@@ -13,7 +13,10 @@ import (
 	"github.com/pulumi/esc/syntax/encoding"
 )
 
-const example = `
+func TestExample(t *testing.T) {
+	t.Parallel()
+
+	const example = `
 imports:
   - green-channel
   - us-west-2
@@ -30,9 +33,33 @@ config:
         environment: prod
 `
 
-func TestExample(t *testing.T) {
+	syntax, diags := encoding.DecodeYAML("<stdin>", yaml.NewDecoder(strings.NewReader(example)), nil)
+	require.Len(t, diags, 0)
+
+	environment, diags := ParseEnvironment([]byte(example), syntax)
+	assert.Len(t, diags, 0)
+
+	assert.Nil(t, environment.Description)
+}
+
+func TestExample2(t *testing.T) {
 	t.Parallel()
 
+	const example = `
+imports:
+  - green-channel
+  - us-west-2
+config:
+  aws:
+    fn::open::aws-oidc:
+      sessionName: site-prod-session
+      roleArn: some-role-arn
+  pulumi:
+    aws:defaultTags:
+      tags:
+        environment: prod
+`
+
 	syntax, diags := encoding.DecodeYAML("<stdin>", yaml.NewDecoder(strings.NewReader(example)), nil)
 	require.Len(t, diags, 0)
 

ast/expr.go

@@ -531,6 +531,11 @@ func tryParseFunction(node *syntax.ObjectNode) (Expr, syntax.Diagnostics, bool)
 	case "fn::toString":
 		parse = parseToString
 	default:
+		if strings.HasPrefix(kvp.Key.Value(), "fn::open::") {
+			parse = parseShortOpen
+			break
+		}
+
 		if strings.HasPrefix(strings.ToLower(kvp.Key.Value()), "fn::") {
 			diags = append(diags, syntax.Warning(kvp.Key.Syntax().Range(),
 				"'fn::' is a reserved prefix",
@@ -604,6 +609,18 @@ func parseOpen(node *syntax.ObjectNode, name *StringExpr, args Expr) (Expr, synt
 	return OpenSyntax(node, name, obj, provider, inputs), diags
 }
 
+func parseShortOpen(node *syntax.ObjectNode, name *StringExpr, args Expr) (Expr, syntax.Diagnostics) {
+	kvp := node.Index(0)
+	provider := strings.TrimPrefix(kvp.Key.Value(), "fn::open::")
+	inputs, ok := args.(*ObjectExpr)
+	if !ok {
+		return nil, syntax.Diagnostics{ExprError(args, fmt.Sprintf("the argument to fn::open::%s must be an object", provider), "")}
+	}
+	p := name.Syntax().(*syntax.StringNode)
+
+	return OpenSyntax(node, name, inputs, StringSyntaxValue(p, provider), inputs), nil
+}
+
 func parseJoin(node *syntax.ObjectNode, name *StringExpr, args Expr) (Expr, syntax.Diagnostics) {
 	list, ok := args.(*ListExpr)
 	if !ok || len(list.Elements) != 2 {