define/await

syndicate/async.rkt

@@ -1,13 +1,15 @@
-#lang syndicate
+#lang racket/base
 ;;; SPDX-License-Identifier: LGPL-3.0-or-later
 ;;; SPDX-FileCopyrightText: Copyright © 2022 Tony Garnock-Jones <tonyg@leastfixedpoint.com>
 
 (provide async
          async?
          suspend
-         await)
+         await
+         define/await)
 
 (require (only-in (submod "actor.rkt" internals) with-active-facet))
+(require "syntax.rkt")
 
 (define prompt-tag (make-continuation-prompt-tag 'syndicate))
 
@@ -45,6 +47,12 @@
                (let ((k (lambda results (stop-facet facet (apply k results)))))
                  body ...)))))
 
+(define-syntax-rule (define/await [name (op args ...)] ...)
+  (define-values (name ...)
+    (await k
+           (define name (op query-result args ...)) ...
+           (sync! this-target (k name ...)))))
+
 (module+ test
   (require "dataspace.rkt")
   (actor-system/dataspace (ds)

syndicate/main.rkt

@@ -9,6 +9,7 @@
          (all-from-out "query.rkt")
          (all-from-out "service.rkt")
          (all-from-out "event-expander.rkt")
+         (all-from-out "async.rkt")
          (all-from-out preserves)
          (all-from-out preserves-schema)
 
@@ -23,6 +24,7 @@
 (require "query.rkt")
 (require "service.rkt")
 (require "event-expander.rkt")
+(require "async.rkt")
 (require preserves)
 (require preserves-schema)
 

syndicate/syntax.rkt

@@ -42,6 +42,7 @@
          during*)
 
 (require racket/match)
+(require racket/splicing)
 (require racket/stxparam)
 (require (for-syntax racket/base))
 (require (for-syntax racket/syntax))
@@ -304,8 +305,9 @@
 (define-syntax (at stx)
   (syntax-case stx ()
     [(_ target-expr items ...)
-     #`(let ((target target-expr))
-         (syntax-parameterize ([this-target (make-rename-transformer #'target)])
+     #`(begin
+         (define target target-expr)
+         (splicing-syntax-parameterize ([this-target (make-rename-transformer #'target)])
            items ...))]))
 
 (define-syntax assert