X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FMethod%2FGenerate%2FAccessor.pm;h=d0ab97061a2654ea7cb7aa931bc0d2d3df78e169;hb=HEAD;hp=f6093eb010423f72a19ae65a9e0e46ebc95bba2b;hpb=4db3a7403e42fab35d8814fca3ad4192547bb997;p=gitmo%2FMoo.git

diff --git a/lib/Method/Generate/Accessor.pm b/lib/Method/Generate/Accessor.pm
index f6093eb..d0ab970 100644
--- a/lib/Method/Generate/Accessor.pm
+++ b/lib/Method/Generate/Accessor.pm
@@ -5,89 +5,173 @@ use Moo::_Utils;
 use base qw(Moo::Object);
 use Sub::Quote;
 use B 'perlstring';
+use Scalar::Util 'blessed';
+use overload ();
+use Module::Runtime qw(use_module);
 BEGIN {
   our $CAN_HAZ_XS =
+    !$ENV{MOO_XS_DISABLE}
+      &&
     _maybe_load_module('Class::XSAccessor')
       &&
-    (Class::XSAccessor->VERSION > 1.06)
+    (eval { Class::XSAccessor->VERSION('1.07') })
   ;
 }
 
+sub _SIGDIE
+{
+  our ($CurrentAttribute, $OrigSigDie);
+  my $sigdie = $OrigSigDie && $OrigSigDie != \&_SIGDIE
+    ? $OrigSigDie
+    : sub { die $_[0] };
+
+  return $sigdie->(@_) if ref($_[0]);
+
+  my $attr_desc = _attr_desc(@$CurrentAttribute{qw(name init_arg)});
+  $sigdie->("$CurrentAttribute->{step} for $attr_desc failed: $_[0]");
+}
+
+sub _die_overwrite
+{
+  my ($pkg, $method, $type) = @_;
+  die "You cannot overwrite a locally defined method ($method) with @{[ $type || 'an accessor' ]}";
+}
+
 sub generate_method {
   my ($self, $into, $name, $spec, $quote_opts) = @_;
+  $spec->{allow_overwrite}++ if $name =~ s/^\+//;
   die "Must have an is" unless my $is = $spec->{is};
   if ($is eq 'ro') {
     $spec->{reader} = $name unless exists $spec->{reader};
   } elsif ($is eq 'rw') {
-    $spec->{accessor} = $name unless exists $spec->{accessor};
+    $spec->{accessor} = $name unless exists $spec->{accessor}
+      or ( $spec->{reader} and $spec->{writer} );
   } elsif ($is eq 'lazy') {
-    $spec->{init_arg} = undef unless exists $spec->{init_arg};
     $spec->{reader} = $name unless exists $spec->{reader};
     $spec->{lazy} = 1;
     $spec->{builder} ||= '_build_'.$name unless $spec->{default};
+  } elsif ($is eq 'rwp') {
+    $spec->{reader} = $name unless exists $spec->{reader};
+    $spec->{writer} = "_set_${name}" unless exists $spec->{writer};
   } elsif ($is ne 'bare') {
     die "Unknown is ${is}";
   }
+  if (exists $spec->{builder}) {
+    if(ref $spec->{builder}) {
+      $self->_validate_codulatable('builder', $spec->{builder},
+        "$into->$name", 'or a method name');
+      $spec->{builder_sub} = $spec->{builder};
+      $spec->{builder} = 1;
+    }
+    $spec->{builder} = '_build_'.$name if ($spec->{builder}||0) eq 1;
+    die "Invalid builder for $into->$name - not a valid method name"
+      if $spec->{builder} !~ /\A[A-Za-z_][A-Za-z0-9_]*(?:::[A-Za-z_][A-Za-z0-9_]*)*\z/;
+  }
+  if (($spec->{predicate}||0) eq 1) {
+    $spec->{predicate} = $name =~ /^_/ ? "_has${name}" : "has_${name}";
+  }
+  if (($spec->{clearer}||0) eq 1) {
+    $spec->{clearer} = $name =~ /^_/ ? "_clear${name}" : "clear_${name}";
+  }
+  if (($spec->{trigger}||0) eq 1) {
+    $spec->{trigger} = quote_sub('shift->_trigger_'.$name.'(@_)');
+  }
+
+  for my $setting (qw( isa coerce )) {
+    next if !exists $spec->{$setting};
+    $self->_validate_codulatable($setting, $spec->{$setting}, "$into->$name");
+  }
+
+  if (exists $spec->{default}) {
+    if (!defined $spec->{default} || ref $spec->{default}) {
+      $self->_validate_codulatable('default', $spec->{default}, "$into->$name", 'or a non-ref');
+    }
+  }
+
+  if (exists $spec->{moosify}) {
+    if (ref $spec->{moosify} ne 'ARRAY') {
+      $spec->{moosify} = [$spec->{moosify}];
+    }
+
+    for my $spec (@{$spec->{moosify}}) {
+      $self->_validate_codulatable('moosify', $spec, "$into->$name");
+    }
+  }
+
   my %methods;
   if (my $reader = $spec->{reader}) {
+    _die_overwrite($into, $reader, 'a reader')
+      if !$spec->{allow_overwrite} && *{_getglob("${into}::${reader}")}{CODE};
     if (our $CAN_HAZ_XS && $self->is_simple_get($name, $spec)) {
       $methods{$reader} = $self->_generate_xs(
-        getters => $into, $reader, $name
+        getters => $into, $reader, $name, $spec
       );
     } else {
-      local $self->{captures} = {};
+      $self->{captures} = {};
       $methods{$reader} =
         quote_sub "${into}::${reader}"
-          => $self->_generate_get($name, $spec)
-          => $self->{captures}
+          => '    die "'.$reader.' is a read-only accessor" if @_ > 1;'."\n"
+             .$self->_generate_get($name, $spec)
+          => delete $self->{captures}
         ;
     }
   }
   if (my $accessor = $spec->{accessor}) {
+    _die_overwrite($into, $accessor, 'an accessor')
+      if !$spec->{allow_overwrite} && *{_getglob("${into}::${accessor}")}{CODE};
     if (
       our $CAN_HAZ_XS
       && $self->is_simple_get($name, $spec)
       && $self->is_simple_set($name, $spec)
     ) {
       $methods{$accessor} = $self->_generate_xs(
-        accessors => $into, $accessor, $name
+        accessors => $into, $accessor, $name, $spec
       );
     } else {
-      local $self->{captures} = {};
+      $self->{captures} = {};
       $methods{$accessor} =
         quote_sub "${into}::${accessor}"
           => $self->_generate_getset($name, $spec)
-          => $self->{captures}
+          => delete $self->{captures}
         ;
     }
   }
   if (my $writer = $spec->{writer}) {
+    _die_overwrite($into, $writer, 'a writer')
+      if !$spec->{allow_overwrite} && *{_getglob("${into}::${writer}")}{CODE};
     if (
       our $CAN_HAZ_XS
       && $self->is_simple_set($name, $spec)
     ) {
       $methods{$writer} = $self->_generate_xs(
-        setters => $into, $writer, $name
+        setters => $into, $writer, $name, $spec
       );
     } else {
-      local $self->{captures} = {};
+      $self->{captures} = {};
       $methods{$writer} =
         quote_sub "${into}::${writer}"
           => $self->_generate_set($name, $spec)
-          => $self->{captures}
+          => delete $self->{captures}
         ;
     }
   }
   if (my $pred = $spec->{predicate}) {
+    _die_overwrite($into, $pred, 'a predicate')
+      if !$spec->{allow_overwrite} && *{_getglob("${into}::${pred}")}{CODE};
     $methods{$pred} =
       quote_sub "${into}::${pred}" =>
-        '    '.$self->_generate_simple_has('$_[0]', $name)."\n"
+        '    '.$self->_generate_simple_has('$_[0]', $name, $spec)."\n"
       ;
   }
+  if (my $pred = $spec->{builder_sub}) {
+    _install_coderef( "${into}::$spec->{builder}" => $spec->{builder_sub} );
+  }
   if (my $cl = $spec->{clearer}) {
+    _die_overwrite($into, $cl, 'a clearer')
+      if !$spec->{allow_overwrite} && *{_getglob("${into}::${cl}")}{CODE};
     $methods{$cl} =
-      quote_sub "${into}::${cl}" => 
-        "    delete \$_[0]->{${\perlstring $name}}\n"
+      quote_sub "${into}::${cl}" =>
+        $self->_generate_simple_clear('$_[0]', $name, $spec)."\n"
       ;
   }
   if (my $hspec = $spec->{handles}) {
@@ -99,27 +183,30 @@ sub generate_method {
         map [ $_ => ref($hspec->{$_}) ? @{$hspec->{$_}} : $hspec->{$_} ],
           keys %$hspec;
       } elsif (!ref($hspec)) {
-        map [ $_ => $_ ], Role::Tiny->methods_provided_by($hspec);
+        map [ $_ => $_ ], use_module('Role::Tiny')->methods_provided_by(use_module($hspec))
       } else {
         die "You gave me a handles of ${hspec} and I have no idea why";
       }
     };
-    foreach my $spec (@specs) {
-      my ($proxy, $target, @args) = @$spec;
-      local $self->{captures} = {};
+    foreach my $delegation_spec (@specs) {
+      my ($proxy, $target, @args) = @$delegation_spec;
+      _die_overwrite($into, $proxy, 'a delegation')
+        if !$spec->{allow_overwrite} && *{_getglob("${into}::${proxy}")}{CODE};
+      $self->{captures} = {};
       $methods{$proxy} =
         quote_sub "${into}::${proxy}" =>
           $self->_generate_delegation($asserter, $target, \@args),
-          $self->{captures}
+          delete $self->{captures}
         ;
     }
   }
   if (my $asserter = $spec->{asserter}) {
-    local $self->{captures} = {};
+    $self->{captures} = {};
+
+
     $methods{$asserter} =
-      quote_sub "${into}::${asserter}" =>
-        'do { '.$self->_generate_get($name, $spec).qq! }||die "Attempted to access '${name}' but it is not set"!,
-        $self->{captures}
+      quote_sub "${into}::${asserter}" => $self->_generate_asserter($name, $spec),
+        delete $self->{captures}
       ;
   }
   \%methods;
@@ -130,7 +217,7 @@ sub is_simple_attribute {
   # clearer doesn't have to be listed because it doesn't
   # affect whether defined/exists makes a difference
   !grep $spec->{$_},
-    qw(lazy default builder isa trigger predicate);
+    qw(lazy default builder coerce isa trigger predicate weak_ref);
 }
 
 sub is_simple_get {
@@ -140,46 +227,87 @@ sub is_simple_get {
 
 sub is_simple_set {
   my ($self, $name, $spec) = @_;
-  !grep $spec->{$_}, qw(isa trigger);
+  !grep $spec->{$_}, qw(coerce isa trigger weak_ref);
+}
+
+sub has_eager_default {
+  my ($self, $name, $spec) = @_;
+  (!$spec->{lazy} and (exists $spec->{default} or $spec->{builder}));
 }
 
 sub _generate_get {
   my ($self, $name, $spec) = @_;
-  my $simple = $self->_generate_simple_get('$_[0]', $name);
+  my $simple = $self->_generate_simple_get('$_[0]', $name, $spec);
   if ($self->is_simple_get($name, $spec)) {
     $simple;
   } else {
-    'do { '.$self->_generate_use_default(
+    $self->_generate_use_default(
       '$_[0]', $name, $spec,
-      $self->_generate_simple_has('$_[0]', $name),
-    ).'; '.$simple.' }';
+      $self->_generate_simple_has('$_[0]', $name, $spec),
+    );
   }
 }
 
+sub generate_simple_has {
+  my $self = shift;
+  $self->{captures} = {};
+  my $code = $self->_generate_simple_has(@_);
+  ($code, delete $self->{captures});
+}
+
 sub _generate_simple_has {
   my ($self, $me, $name) = @_;
   "exists ${me}->{${\perlstring $name}}";
 }
 
+sub _generate_simple_clear {
+  my ($self, $me, $name) = @_;
+  "    delete ${me}->{${\perlstring $name}}\n"
+}
+
 sub generate_get_default {
   my $self = shift;
-  local $self->{captures} = {};
+  $self->{captures} = {};
   my $code = $self->_generate_get_default(@_);
-  ($code, $self->{captures});
+  ($code, delete $self->{captures});
+}
+
+sub generate_use_default {
+  my $self = shift;
+  $self->{captures} = {};
+  my $code = $self->_generate_use_default(@_);
+  ($code, delete $self->{captures});
 }
 
 sub _generate_use_default {
   my ($self, $me, $name, $spec, $test) = @_;
-  $self->_generate_simple_set(
-    $me, $name, $self->_generate_get_default($me, $name, $spec)
-  ).' unless '.$test;
+  my $get_value = $self->_generate_get_default($me, $name, $spec);
+  if ($spec->{coerce}) {
+    $get_value = $self->_generate_coerce(
+      $name, $get_value,
+      $spec->{coerce}
+    )
+  }
+  $test." ? \n"
+  .$self->_generate_simple_get($me, $name, $spec)."\n:"
+  .($spec->{isa}
+    ? "    do {\n      my \$value = ".$get_value.";\n"
+      ."      ".$self->_generate_isa_check($name, '$value', $spec->{isa}).";\n"
+      ."      ".$self->_generate_simple_set($me, $name, $spec, '$value')."\n"
+      ."    }\n"
+    : '    ('.$self->_generate_simple_set($me, $name, $spec, $get_value).")\n");
 }
 
 sub _generate_get_default {
   my ($self, $me, $name, $spec) = @_;
-  $spec->{default}
-    ? $self->_generate_call_code($name, 'default', $me, $spec->{default})
-    : "${me}->${\$spec->{builder}}"
+  if (exists $spec->{default}) {
+    ref $spec->{default}
+      ? $self->_generate_call_code($name, 'default', $me, $spec->{default})
+      : perlstring $spec->{default};
+  }
+  else {
+    "${me}->${\$spec->{builder}}"
+  }
 }
 
 sub generate_simple_get {
@@ -195,21 +323,31 @@ sub _generate_simple_get {
 
 sub _generate_set {
   my ($self, $name, $spec) = @_;
-  my $simple = $self->_generate_simple_set('$_[0]', $name, '$_[1]');
   if ($self->is_simple_set($name, $spec)) {
-    $simple;
+    $self->_generate_simple_set('$_[0]', $name, $spec, '$_[1]');
   } else {
-    my ($trigger, $isa_check) = @{$spec}{qw(trigger isa)};
-    my $code = "do {\n";
+    my ($coerce, $trigger, $isa_check) = @{$spec}{qw(coerce trigger isa)};
+    my $value_store = '$_[0]';
+    my $code;
+    if ($coerce) {
+      $value_store = '$value';
+      $code = "do { my (\$self, \$value) = \@_;\n"
+        ."        \$value = "
+        .$self->_generate_coerce($name, $value_store, $coerce).";\n";
+    }
+    else {
+      $code = "do { my \$self = shift;\n";
+    }
     if ($isa_check) {
-      $code .= 
-        "        ".$self->_generate_isa_check($name, '$_[1]', $isa_check).";\n";
+      $code .=
+        "        ".$self->_generate_isa_check($name, $value_store, $isa_check).";\n";
     }
+    my $simple = $self->_generate_simple_set('$self', $name, $spec, $value_store);
     if ($trigger) {
-      my $fire = $self->_generate_trigger($name, '$_[0]', '$value', $trigger);
+      my $fire = $self->_generate_trigger($name, '$self', $value_store, $trigger);
       $code .=
-        "        my \$value = ".$simple.";\n        ".$fire.";\n"
-        ."        \$value;\n";
+        "        ".$simple.";\n        ".$fire.";\n"
+        ."        $value_store;\n";
     } else {
       $code .= "        ".$simple.";\n";
     }
@@ -217,12 +355,35 @@ sub _generate_set {
     $code;
   }
 }
-  
+
+sub generate_coerce {
+  my $self = shift;
+  $self->{captures} = {};
+  my $code = $self->_generate_coerce(@_);
+  ($code, delete $self->{captures});
+}
+
+sub _attr_desc {
+  my ($name, $init_arg) = @_;
+  return perlstring($name) if !defined($init_arg) or $init_arg eq $name;
+  return perlstring($name).' (constructor argument: '.perlstring($init_arg).')';
+}
+
+sub _generate_coerce {
+  my ($self, $name, $value, $coerce, $init_arg) = @_;
+  $self->_generate_die_prefix(
+    $name,
+    "coercion",
+    $init_arg,
+    $self->_generate_call_code($name, 'coerce', "${value}", $coerce)
+  );
+}
+
 sub generate_trigger {
   my $self = shift;
-  local $self->{captures} = {};
+  $self->{captures} = {};
   my $code = $self->_generate_trigger(@_);
-  ($code, $self->{captures});
+  ($code, delete $self->{captures});
 }
 
 sub _generate_trigger {
@@ -232,29 +393,54 @@ sub _generate_trigger {
 
 sub generate_isa_check {
   my ($self, @args) = @_;
-  local $self->{captures} = {};
+  $self->{captures} = {};
   my $code = $self->_generate_isa_check(@args);
-  ($code, $self->{captures});
+  ($code, delete $self->{captures});
+}
+
+sub _generate_die_prefix {
+  my ($self, $name, $prefix, $arg, $inside) = @_;
+  "do {\n"
+  .'  local $Method::Generate::Accessor::CurrentAttribute = {'
+  .'    init_arg => '.(defined $arg ? B::perlstring($arg) : 'undef') . ",\n"
+  .'    name     => '.B::perlstring($name).",\n"
+  .'    step     => '.B::perlstring($prefix).",\n"
+  ."  };\n"
+  .'  local $Method::Generate::Accessor::OrigSigDie = $SIG{__DIE__};'."\n"
+  .'  local $SIG{__DIE__} = \&Method::Generate::Accessor::_SIGDIE;'."\n"
+  .$inside
+  ."}\n"
 }
 
 sub _generate_isa_check {
-  my ($self, $name, $value, $check) = @_;
-  $self->_generate_call_code($name, 'isa_check', $value, $check);
+  my ($self, $name, $value, $check, $init_arg) = @_;
+  $self->_generate_die_prefix(
+    $name,
+    "isa check",
+    $init_arg,
+    $self->_generate_call_code($name, 'isa_check', $value, $check)
+  );
 }
 
 sub _generate_call_code {
   my ($self, $name, $type, $values, $sub) = @_;
+  $sub = \&{$sub} if blessed($sub);  # coderef if blessed
   if (my $quoted = quoted_from_sub($sub)) {
+    my $local = 1;
+    if ($values eq '@_' || $values eq '$_[0]') {
+      $local = 0;
+      $values = '@_';
+    }
     my $code = $quoted->[1];
-    my $at_ = 'local @_ = ('.$values.');';
     if (my $captures = $quoted->[2]) {
       my $cap_name = qq{\$${type}_captures_for_${name}};
       $self->{captures}->{$cap_name} = \$captures;
-      return "do {\n".'      '.$at_."\n"
-        .Sub::Quote::capture_unroll($cap_name, $captures, 6)
-        ."     ${code}\n    }";
+      Sub::Quote::inlinify(
+        $code, $values, Sub::Quote::capture_unroll($cap_name, $captures, 6), $local
+      );
+    } else {
+      Sub::Quote::inlinify($code, $values, undef, $local);
     }
-    'do { local @_ = ('.$values.'); '.$code.' }';
   } else {
     my $cap_name = qq{\$${type}_for_${name}};
     $self->{captures}->{$cap_name} = \$sub;
@@ -264,53 +450,69 @@ sub _generate_call_code {
 
 sub generate_populate_set {
   my $self = shift;
-  local $self->{captures} = {};
+  $self->{captures} = {};
   my $code = $self->_generate_populate_set(@_);
-  ($code, $self->{captures});
+  ($code, delete $self->{captures});
 }
 
 sub _generate_populate_set {
-  my ($self, $me, $name, $spec, $source, $test) = @_;
-  if (!$spec->{lazy} and
-        ($spec->{default} or $spec->{builder})) {
+  my ($self, $me, $name, $spec, $source, $test, $init_arg) = @_;
+  if ($self->has_eager_default($name, $spec)) {
     my $get_indent = ' ' x ($spec->{isa} ? 6 : 4);
-    my $get_value = 
-      "(\n${get_indent}  ${test}\n${get_indent}   ? ${source}\n${get_indent}   : "
-        .$self->_generate_get_default(
-          '$new', $_, $spec
-        )
-        ."\n${get_indent})";
+    my $get_default = $self->_generate_get_default(
+                        '$new', $name, $spec
+                      );
+    my $get_value =
+      defined($spec->{init_arg})
+        ? "(\n${get_indent}  ${test}\n${get_indent}   ? ${source}\n${get_indent}   : "
+            .$get_default
+            ."\n${get_indent})"
+        : $get_default;
+    if ($spec->{coerce}) {
+      $get_value = $self->_generate_coerce(
+        $name, $get_value,
+        $spec->{coerce}, $init_arg
+      )
+    }
     ($spec->{isa}
       ? "    {\n      my \$value = ".$get_value.";\n      "
         .$self->_generate_isa_check(
-          $name, '$value', $spec->{isa}
+          $name, '$value', $spec->{isa}, $init_arg
         ).";\n"
-        .'      '.$self->_generate_simple_set($me, $name, '$value').";\n"
+        .'      '.$self->_generate_simple_set($me, $name, $spec, '$value').";\n"
         ."    }\n"
-      : '    '.$self->_generate_simple_set($me, $name, $get_value).";\n"
+      : '    '.$self->_generate_simple_set($me, $name, $spec, $get_value).";\n"
     )
     .($spec->{trigger}
       ? '    '
         .$self->_generate_trigger(
-          $name, $me, $self->_generate_simple_get($me, $name),
+          $name, $me, $self->_generate_simple_get($me, $name, $spec),
           $spec->{trigger}
         )." if ${test};\n"
       : ''
     );
   } else {
     "    if (${test}) {\n"
+      .($spec->{coerce}
+        ? "      $source = "
+          .$self->_generate_coerce(
+            $name, $source,
+            $spec->{coerce}, $init_arg
+          ).";\n"
+        : ""
+      )
       .($spec->{isa}
         ? "      "
           .$self->_generate_isa_check(
-            $name, $source, $spec->{isa}
+            $name, $source, $spec->{isa}, $init_arg
           ).";\n"
         : ""
       )
-      ."      ".$self->_generate_simple_set($me, $name, $source).";\n"
+      ."      ".$self->_generate_simple_set($me, $name, $spec, $source).";\n"
       .($spec->{trigger}
         ? "      "
           .$self->_generate_trigger(
-            $name, $me, $self->_generate_simple_get($me, $name),
+            $name, $me, $self->_generate_simple_get($me, $name, $spec),
             $spec->{trigger}
           ).";\n"
         : ""
@@ -319,30 +521,68 @@ sub _generate_populate_set {
   }
 }
 
-sub generate_multi_set {
-  my ($self, $me, $to_set, $from) = @_;
-  "\@{${me}}{qw(${\join ' ', @$to_set})} = $from";
-}
-
-sub generate_simple_set {
-  my $self = shift;
-  local $self->{captures} = {};
-  my $code = $self->_generate_simple_set(@_);
-  ($code, $self->{captures});
+sub _generate_core_set {
+  my ($self, $me, $name, $spec, $value) = @_;
+  my $name_str = perlstring $name;
+  "${me}->{${name_str}} = ${value}";
 }
 
 sub _generate_simple_set {
-  my ($self, $me, $name, $value) = @_;
+  my ($self, $me, $name, $spec, $value) = @_;
   my $name_str = perlstring $name;
-  "${me}->{${name_str}} = ${value}";
+  my $simple = $self->_generate_core_set($me, $name, $spec, $value);
+
+  if ($spec->{weak_ref}) {
+    require Scalar::Util;
+    my $get = $self->_generate_simple_get($me, $name, $spec);
+
+    # Perl < 5.8.3 can't weaken refs to readonly vars
+    # (e.g. string constants). This *can* be solved by:
+    #
+    #Internals::SetReadWrite($foo);
+    #Scalar::Util::weaken ($foo);
+    #Internals::SetReadOnly($foo);
+    #
+    # but requires XS and is just too damn crazy
+    # so simply throw a better exception
+    my $weak_simple = "do { Scalar::Util::weaken(${simple}); no warnings 'void'; $get }";
+    Moo::_Utils::lt_5_8_3() ? <<"EOC" : $weak_simple;
+      eval { Scalar::Util::weaken($simple); 1 }
+        ? do { no warnings 'void'; $get }
+        : do {
+          if( \$@ =~ /Modification of a read-only value attempted/) {
+            require Carp;
+            Carp::croak( sprintf (
+              'Reference to readonly value in "%s" can not be weakened on Perl < 5.8.3',
+              $name_str,
+            ) );
+          } else {
+            die \$@;
+          }
+        }
+EOC
+  } else {
+    $simple;
+  }
 }
 
 sub _generate_getset {
   my ($self, $name, $spec) = @_;
   q{(@_ > 1}."\n      ? ".$self->_generate_set($name, $spec)
-    ."\n      : ".$self->_generate_get($name)."\n    )";
+    ."\n      : ".$self->_generate_get($name, $spec)."\n    )";
 }
 
+sub _generate_asserter {
+  my ($self, $name, $spec) = @_;
+
+  "do {\n"
+   ."  my \$val = ".$self->_generate_get($name, $spec).";\n"
+   ."  unless (".$self->_generate_simple_has('$_[0]', $name, $spec).") {\n"
+   .qq!    die "Attempted to access '${name}' but it is not set";\n!
+   ."  }\n"
+   ."  \$val;\n"
+   ."}\n";
+}
 sub _generate_delegation {
   my ($self, $asserter, $target, $args) = @_;
   my $arg_string = do {
@@ -362,9 +602,29 @@ sub _generate_xs {
   my ($self, $type, $into, $name, $slot) = @_;
   Class::XSAccessor->import(
     class => $into,
-    $type => { $name => $slot }
+    $type => { $name => $slot },
+    replace => 1,
   );
   $into->can($name);
 }
 
+sub default_construction_string { '{}' }
+
+sub _validate_codulatable {
+  my ($self, $setting, $value, $into, $appended) = @_;
+  my $invalid = "Invalid $setting '" . overload::StrVal($value)
+    . "' for $into not a coderef";
+  $invalid .= " $appended" if $appended;
+
+  unless (ref $value and (ref $value eq 'CODE' or blessed($value))) {
+    die "$invalid or code-convertible object";
+  }
+
+  unless (eval { \&$value }) {
+    die "$invalid and could not be converted to a coderef: $@";
+  }
+
+  1;
+}
+
 1;