[glue/run.pir] when running as a main program, create $*PROGRAM_NAME …

…and @*ARGS

src/glue/run.pir

@@ -9,7 +9,10 @@ src/glue/run.pir - code to initiate execution of a Perl 6 program
 =item !UNIT_START(mainline, args)
 
 Invoke the code given by mainline, using C<args> as the initial
-(command-line) arguments.  
+(command-line) arguments.  The method C<comp_unit($/)> in
+F<Perl6/Actions.pm> generates two calls to this sub, one for
+executables and one for libraries, and pushes them into the AST
+of the compilation unit.
 
 =cut
 
@@ -18,6 +21,29 @@ Invoke the code given by mainline, using C<args> as the initial
     .param pmc mainline
     .param pmc args            :slurpy
 
+    # Ignore the args when executed as a library (not main program)
+    unless args goto unit_start_0
+
+    # args    is a ResizablePMCArray containing only one entry
+    # args[0] is also a ResizablePMCArray, of String entries, containing 
+    #         the program name or '-e' in args[0][0], followed by
+    #         optional command line arguments in args[0][1] etc.
+    $P0 = args[0]
+    # Ignore the args when executed as a library (not main program)
+    unless $P0 goto unit_start_0
+
+    # The first args string belongs in $*PROGRAM_NAME
+    $P1 = shift $P0      # the first arg is the program name
+    set_hll_global '$PROGRAM_NAME', $P1
+
+    # The remaining args strings belong in @*ARGS
+    $P1 = new ['Parcel']
+    splice $P1, $P0, 0, 0
+    $P2 = new ['Array']
+    $P2.'!STORE'($P1)
+    set_hll_global '@ARGS', $P2
+  unit_start_0:
+
     # INIT time
     '!fire_phasers'('INIT')
     $P0 = mainline()