Apply a slightly refactored and tweaked patch from sorear++ to add a …

…first cut of loading and importing from foreign libraries. Works with Blizkost (tested here on Win32). Not complete/final, but should let people start playing with a few aspects of Perl 5 interop.

src/Perl6/Module/Loader.pm

@@ -5,7 +5,12 @@ class Perl6::Module::Loader;
 our %LOADED;
 
 method need($name, %name_adverbs?) {
-    # Use locator to find the module.
+    # From another HLL?
+    if %name_adverbs<from> {
+        return self.need_foreign($name, %name_adverbs);
+    }
+
+    # Otherwise, use the Perl 6 module locator.
     my @inc     := pir::get_hll_global__PS('@INC');
     my $pm_file := %name_adverbs<ver> || %name_adverbs<auth> ??
         Perl6::Module::Locator.find_module($name, @inc, %name_adverbs<ver>, %name_adverbs<auth>) !!
@@ -48,10 +53,63 @@ method need($name, %name_adverbs?) {
     1;
 }
 
+method need_foreign($name, %name_adverbs) {
+    # If it's a foreign module, we delegate most of the work to the
+    # other language.  However, we still need to install a namespace
+    # alias in order for import and qualified references to work.
+
+    my $lang := %name_adverbs<from>;
+    my $orig_name := $name; # TODO: Implement :from<lang not.coloned.Name>
+
+    pir::load_language__vs($lang);
+
+    my $lsm := pir::compreg__ps($lang);
+    my $mod := $lsm.load_module($orig_name);
+    my $ns  := $lsm.get_namespace($mod);
+
+    # Perl6's two phase import mechanism complicates things slightly
+    # We need to remember the $lsm to we can get at the exports *later*
+    my $exports_closure := sub() {
+        # TODO: Import flags
+        my %raw_exports := $lsm.get_exports($mod);
+        my %exports;
+
+        my %subs := %raw_exports<sub> // pir::root_new__PP(<parrot Hash>);
+        for %subs {
+            %exports{'&' ~ $_.key} := %subs{$_.key};
+        }
+        # TODO: Non-sub exports
+
+        %exports;
+    };
+    pir::setprop($ns, '!rakudo-export-closure', $exports_closure);
+
+    # XXX This alias wants to be lexical, but for now we put it into the
+    # namespace.
+    my @nsparts := pir::split__PSS('::', $name);
+    my $lastpart := @nsparts.pop;
+    pir::set_hll_global__vPSP(@nsparts, '&' ~ $lastpart, sub() { $mod });
+    pir::set_hll_global__vPSP(@nsparts,       $lastpart, $ns);
+
+    return 1;
+}
+
 method get_imports($name) {
     # Look up default export namespace.
-    # XXX Here is where we need to support custom tags.
     my @nsparts := pir::split__PSS('::', $name);
+
+    # If it's an alias to a foreign namespace, we attached an export closure
+    # to it at need time.
+    my $ns := pir::get_hll_namespace__PP(@nsparts);
+    unless pir::isnull($ns) {
+        my $closure := pir::getprop('!rakudo-export-closure', $ns);
+        unless pir::isnull($closure) {
+            return $closure();
+        }
+    }
+
+    # Otherwise, just go looking in EXPORT::DEFAULT namespace.
+    # XXX Here is where we need to support custom tags.
     @nsparts.push('EXPORT');
     @nsparts.push('DEFAULT');
     return pir::get_hll_namespace__PP(@nsparts);
@@ -62,10 +120,10 @@ method stub_lexical_imports($name, $block_ast) {
     unless pir::isnull__IP(%imports) {
         for %imports {
             $block_ast[0].push(PAST::Var.new(
-                :name(~$_), :scope('lexical'), :isdecl(1),
+                :name($_.key), :scope('lexical'), :isdecl(1),
                 :viviself(PAST::Op.new( :pirop('null P')) )
             ));
-            $block_ast.symbol(~$_, :scope('lexical'));
+            $block_ast.symbol($_.key, :scope('lexical'));
         }
     }
 }
@@ -85,5 +143,6 @@ method import($name) {
             $targetns{$_.key} := $_.value;
         }
     }
+
     1;
 }