Add command-defined? so various files can test for features being

present or not.

diff --git a/v7/src/edwin/macros.scm b/v7/src/edwin/macros.scm
index 0931fa96d242a94628f1abaede0dcf033ae824cc..a4d5c96cf40adafa2082e9729f3cd529c2991a8f 100644 (file)
--- a/v7/src/edwin/macros.scm
+++ b/v7/src/edwin/macros.scm
@@ -1,8 +1,8 @@
 ;;; -*-Scheme-*-
 ;;;
-;;;    $Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/edwin/macros.scm,v 1.54 1992/01/09 17:47:27 cph Exp $
+;;;    $Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/edwin/macros.scm,v 1.55 1992/08/28 18:46:48 jinx Exp $
 ;;;
-;;;    Copyright (c) 1986, 1989-92 Massachusetts Institute of Technology
+;;;    Copyright (c) 1986, 1989-1992 Massachusetts Institute of Technology
 ;;;
 ;;;    This material was developed by the Scheme project at the
 ;;;    Massachusetts Institute of Technology, Department of
@@ -129,6 +129,14 @@
     `(COMMAND-PROCEDURE
       ,(command-name->scheme-name (canonicalize-name name)))))
 
+(syntax-table-define edwin-syntax-table 'COMMAND-DEFINED?
+  (lambda (name)
+    (let ((variable-name (command-name->scheme-name (canonicalize-name name))))
+      `(let ((env (->environment '(EDWIN))))
+        (and (environment-bound? env ',variable-name)
+             (not (lexical-unassigned? env
+                                       ',variable-name)))))))
+
 (define (command-name->scheme-name name)
   (symbol-append 'EDWIN-COMMAND$ name))