A further round of MOP code simplifications.

We've relied in various places on methods that Parrot's PMCs provide,
but that it's not reasonable to expect a ground-up 6model runtime to
offer. In general, the only things that define internal methods are
the KnowHOW and KnowHOWAttribute, from which everything else is built.
By keeping the MOP simpler, it means we can keep the runtime leaner
and write more of NQP in NQP. This isn't the entire set of changes we
need, but many of them.

src/how/NQPClassHOW.pm

@@ -156,12 +156,12 @@ knowhow NQPClassHOW {
             nqp::die("Can only re-parent a class with exactly one parent");
         }
         for @!parents[0].HOW.mro(@!parents[0]) {
-            if +$_.HOW.attributes($_, :local) {
+            if nqp::elems($_.HOW.attributes($_, :local)) {
                 nqp::die("Can only re-parent a class whose parent has no attributes");
             }
         }
         for $new_parent.HOW.mro($new_parent) {
-            if +$_.HOW.attributes($_, :local) {
+            if nqp::elems($_.HOW.attributes($_, :local)) {
                 nqp::die("Can only re-parent to a class with no attributes");
             }
         }
@@ -210,7 +210,7 @@ knowhow NQPClassHOW {
             my @specialized_roles;
             for @!roles {
                 my $ins := $_.HOW.specialize($_, $obj);
-                @specialized_roles.push($ins);
+                nqp::push(@specialized_roles, $ins);
                 nqp::push(@!done, $_);
                 nqp::push(@!done, $ins);
             }
@@ -316,15 +316,15 @@ knowhow NQPClassHOW {
                 # immediate parents and merge.
                 my @merge_list;
                 for @immediate_parents {
-                    @merge_list.push(compute_c3_mro($_));
+                    nqp::push(@merge_list, compute_c3_mro($_));
                 }
-                @merge_list.push(@immediate_parents);
+                nqp::push(@merge_list, @immediate_parents);
                 @result := c3_merge(@merge_list);
             }
         }
 
         # Put this class on the start of the list, and we're done.
-        @result.unshift($class);
+        nqp::unshift(@result, $class);
         return @result;
     }
 
@@ -381,7 +381,7 @@ knowhow NQPClassHOW {
             my @new_list;
             for @merge_list[$i] {
                 unless $_ =:= $accepted {
-                    @new_list.push($_);
+                    nqp::push(@new_list, $_);
                 }
             }
             @merge_list[$i] := @new_list;
@@ -391,23 +391,28 @@ knowhow NQPClassHOW {
         # Need to merge what remains of the list, then put what was accepted on
         # the start of the list, and we're done.
         @result := c3_merge(@merge_list);
-        @result.unshift($accepted);
+        nqp::unshift(@result, $accepted);
         return @result;
     }
 
     method publish_type_cache($obj) {
         my @tc;
-        for @!mro { @tc.push($_); }
-        for @!done { @tc.push($_); }
+        for @!mro { nqp::push(@tc, $_); }
+        for @!done { nqp::push(@tc, $_); }
         nqp::settypecache($obj, @tc)
     }
+
+    sub reverse(@in) {
+        my @out;
+        for @in { nqp::unshift(@out, $_) }
+        @out
+    }
 
     method publish_method_cache($obj) {
         # Walk MRO and add methods to cache, unless another method
         # lower in the class hierarchy "shadowed" it.
         my %cache;
-        my @mro_reversed := nqp::clone(@!mro);
-        @mro_reversed.reverse();
+        my @mro_reversed := reverse(@!mro);
         for @mro_reversed {
             for $_.HOW.method_table($_) {
                 %cache{$_.key} := $_.value;
@@ -448,8 +453,7 @@ knowhow NQPClassHOW {
 
     method publish_parrot_vtablee_handler_mapping($obj) {
         my %mapping;
-        my @mro_reversed := nqp::clone(@!mro);
-        @mro_reversed.reverse();
+        my @mro_reversed := reverse(@!mro);
         for @mro_reversed {
             for $_.HOW.parrot_vtable_handler_mappings($_, :local(1)) {
                 %mapping{$_.key} := $_.value;
@@ -554,7 +558,7 @@ knowhow NQPClassHOW {
             my @meths;
             for @!mro {
                 for $_.HOW.methods($_, :local) {
-                    @meths.push($_)
+                    nqp::push(@meths, $_)
                 }
             }
             @meths
@@ -581,13 +585,13 @@ knowhow NQPClassHOW {
         my @attrs;
         if $local {
             for %!attributes {
-                @attrs.push($_.value);
+                nqp::push(@attrs, $_.value);
             }
         }
         else {
             for @!mro {
                 for $_.HOW.attributes($_, :local) {
-                    @attrs.push($_);
+                    nqp::push(@attrs, $_);
                 }
             }
         }

src/how/NQPConcreteRoleHOW.pm

@@ -121,7 +121,7 @@ knowhow NQPConcreteRoleHOW {
     method methods($obj, :$local) {
         my @meths;
         for %!methods {
-            @meths.push($_.value);
+            nqp::push(@meths, $_.value);
         }
         @meths
     }
@@ -141,7 +141,7 @@ knowhow NQPConcreteRoleHOW {
     method attributes($obj, :$local) {
         my @attrs;
         for %!attributes {
-            @attrs.push($_.value);
+            nqp::push(@attrs, $_.value);
         }
         @attrs
     }

src/how/NQPParametricRoleHOW.pm

@@ -164,7 +164,7 @@ knowhow NQPParametricRoleHOW {
     method methods($obj, :$local) {
         my @meths;
         for %!methods {
-            @meths.push($_.value);
+            nqp::push(@meths, $_.value);
         }
         @meths
     }
@@ -180,7 +180,7 @@ knowhow NQPParametricRoleHOW {
     method attributes($obj, :$local) {
         my @attrs;
         for %!attributes {
-            @attrs.push($_.value);
+            nqp::push(@attrs, $_.value);
         }
         @attrs
     }

src/how/RoleToRoleApplier.pm

@@ -21,7 +21,7 @@ knowhow RoleToRoleApplier {
                     }
                 }
                 unless $found {
-                    @meth_list.push($meth);
+                    nqp::push(@meth_list, $meth);
                 }
             }
         }
@@ -80,7 +80,7 @@ knowhow RoleToRoleApplier {
 
             # Build up full list.
             # XXX Not really right yet...
-            @all_roles.push($_);
+            nqp::push(@all_roles, $_);
         }
 
         return @all_roles;