Update packages

elpa/racket-mode-20181004.309/racket/gui.rkt

@@ -0,0 +1,42 @@
+#lang at-exp racket/base
+
+(require (only-in racket/format ~a)
+         "util.rkt")
+
+(provide gui-required?
+         require-gui
+         txt/gui)
+
+(define root-eventspace #f) ;#f until racket/gui/base required first time
+
+(define (gui-required?)
+  (and root-eventspace #t))
+
+;; Extra explanation for situations like issue 93, entering `(require
+;; redex)` in the REPL, as opposed to having it in a .rkt file.
+(define more-explanation
+  @~a{The namespace was reset. Any `require`s you entered in the REPL were "undone".
+      This includes the `require` you just entered. You may want to enter it again.})
+
+;; This must be called from the main thread, under the main custodian!
+(define (require-gui in-repl?)
+  (when (gui-required?)
+    (error 'require-gui "Already required"))
+  (display-commented "On-demand, one-time instantiation of racket/gui/base.")
+  (when in-repl?
+    (display-commented more-explanation))
+  (define current-eventspace (gui-dyn-req 'current-eventspace))
+  (define make-eventspace    (gui-dyn-req 'make-eventspace))
+  (set! root-eventspace (make-eventspace))
+  (current-eventspace root-eventspace))
+
+;; Like mz/mr from racket/sandbox.
+(define-syntax txt/gui
+  (syntax-rules ()
+    [(_ txtval guisym)
+     (if (gui-required?)
+         (gui-dyn-req 'guisym)
+         txtval)]))
+
+(define (gui-dyn-req sym)
+  (dynamic-require 'racket/gui/base sym))