add types to Proposition and PropositionSequence

[scpubgit/DX.git] / lib / DX / PropositionSequence.pm

diff --git a/lib/DX/PropositionSequence.pm b/lib/DX/PropositionSequence.pm
index 2becac1..1756e15 100644 (file)
--- a/lib/DX/PropositionSequence.pm
+++ b/lib/DX/PropositionSequence.pm
@@ -1,17 +1,47 @@
 package DX::PropositionSequence;
 
-use Types::Standard qw(ArrayRef);
+use Types::Standard qw(HashRef);
 use DX::Class;
 
-has members => (is => 'ro', isa => ArrayRef[Proposition], required => 1);
+has members => (is => 'ro', isa => PropositionList, required => 1);
+
+has external_names => (is => 'ro', isa => HashRef[One], required => 1);
+
+has internal_names => (is => 'ro', isa => HashRef[One], required => 1);
 
 sub new_empty {
-  shift->new(members => []);
+  shift->new(
+    members => [],
+    external_names => {},
+    internal_names => {},
+  );
 }
 
-sub but_append_proposition {
+sub with_additional_proposition {
   my ($self, $prop) = @_;
-  $self->but(members => [ @{$self->members}, $prop ];
+  my %already_names = (
+    %{$self->external_names}, %{$self->internal_names}
+  );
+  my @fail;
+  if (
+    my @missing = grep !$already_names{$_}, sort keys %{$prop->required_names}
+  ) {
+    push @fail,
+      "  variables ".join(' ', @missing)." required but not in scope";
+  }
+  if (
+    my @shadow = grep $already_names{$_}, keys %{$prop->introduced_names}
+  ) {
+    push @fail,
+      "  new variables ".join(' ', @shadow)." are already in scope";
+  }
+  if (@fail) {
+    die join("\n", "Can't add call to ${\$prop->predicate}:", @fail, '');
+  }
+  $self->but(
+    members => [ @{$self->members}, $prop ],
+    internal_names => { %{$self->internal_names}, %{$prop->introduced_names} },
+  );
 }
 
 1;