Re: Patch for wrong no declaration seen for command-line-arguments

[Per Bothner <per@bothner.com>]

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On 09/11/2013 08:42 PM, Matthieu Vachon wrote:
> Hi Per,
>
> Here my try at fixing the incorrect warning that occurs when
> generating a main method and using the `command-line-arguments`. It's
> probably not the optimal way to fix the issue but I hope it is good
> enough to be included in the trunk.

Thanks for prodding me into action.  Your patch makes me think
that having a special case for command-line-arguments is the wrong approach.

Please try the attached patch instead.  That is a simpler/cleaner
solution.

You might also consider using the (command-line) procedure.
It is specified by R6RS and R7RS so is more portable.
It also gives you the "command" used to invoke the application
(roughly argv[0]).  The attached patch provides a more informative
result for (car (command-line)) - rather than plain "kawa".
I'd be interested in feedback in how portable it is: Windows,
MacOS, non-Sun/Oracle VMs (including ones that don't set the
sun.java.command property).  (I also working on updating the
documentation.)
-- 
	--Per Bothner
per@bothner.com   http://per.bothner.com/

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Index: gnu/expr/ApplicationMainSupport.java
===================================================================
--- gnu/expr/ApplicationMainSupport.java	(revision 7583)
+++ gnu/expr/ApplicationMainSupport.java	(working copy)
@@ -43,7 +43,6 @@
   public static void setArgs (String[] args, int arg_start)
   {
     int nargs = args.length - arg_start;
-    Object[] array = new Object[nargs];
     if (arg_start == 0)
      commandLineArgArray = args;
     else
@@ -53,12 +52,10 @@
 	  strings[i] = args[i+arg_start];
 	commandLineArgArray = strings;
       }
-    for (int i = nargs;  --i >= 0; )
-      array[i] = new FString (args[i + arg_start]);
-    commandLineArguments = new FVector (array);  // FIXME scsh has list
-    // FIXME scsh also has command-line proc
-    Environment.getCurrent().put("command-line-arguments",
-                                 commandLineArguments);
+    
+    Object[] array = new Object[nargs];
+    System.arraycopy(args, arg_start, array, 0, nargs);
+    commandLineArguments = new ConstVector(array);  // FIXME scsh has list
   }
 
   public static boolean processSetProperty (String arg)
Index: kawa/lib/rnrs/programs.scm
===================================================================
--- kawa/lib/rnrs/programs.scm	(revision 7583)
+++ kawa/lib/rnrs/programs.scm	(working copy)
@@ -3,8 +3,32 @@
 (require <kawa.lib.prim_syntax>)
 
 (define (command-line) :: list
-  (let ((arg0 "kawa")) ;; FIXME
-    (cons arg0 (gnu.lists.LList:makeList gnu.expr.ApplicationMainSupport:commandLineArgArray 0))))
+  (let* ((rest
+          (gnu.lists.LList:makeList
+           gnu.expr.ApplicationMainSupport:commandLineArgArray 0))
+         (command ::java.lang.String
+                  (try-catch
+                   (let ((raw (java.lang.System:getProperty
+                               "sun.java.command")))
+                     (if (eq? raw #!null) #!null
+                         ;; Strip off the tail of the property value that
+                         ;; duplicates the rest value.
+                         (let* ((frest (format #f "~{ ~a~}" rest))
+                                (rlen (raw:length))
+                                (flen (frest:length))
+                                (alen (- rlen flen)))
+                           (cond ((= flen 0)
+                                  raw)
+                                 ;; Sanity check
+                                 ((and (>= alen 0)
+                                       ((raw:substring alen):equals frest))
+                                  (raw:substring 0 alen))
+                                 (else
+                                  #!null)))))
+                   (exp java.lang.Throwable #!null)))
+         (arg0 (if (eq? command #!null) "kawa"
+                   ("java ":concat command))))
+    (cons arg0 rest)))
 
 (define (exit #!optional (code 0)) :: #!void
   (invoke-static <output-port> 'runCleanups)
Index: kawa/standard/Scheme.java
===================================================================
--- kawa/standard/Scheme.java	(revision 7583)
+++ kawa/standard/Scheme.java	(working copy)
@@ -565,6 +565,8 @@
 
       defProcStFld("exit", "kawa.lib.rnrs.programs");
       defProcStFld("command-line", "kawa.lib.rnrs.programs");
+      defAliasStFld("command-line-arguments", 
+                    "gnu.expr.ApplicationMainSupport", "commandLineArguments");
 
       defProcStFld("bitwise-arithmetic-shift",
                    "gnu.kawa.functions.BitwiseOp", "ashift");