package DX::Step::ConsiderProposition;
+use DX::Value::Unset;
+use DX::ActionBuilder::UnsetValue;
use DX::Class;
with 'DX::Role::Step';
sub apply_to {
my ($self, $ss) = @_;
my $hyp = $ss->current_hypothesis;
- if (my $step = $self->proposition->resolve_for($hyp->scope)) {
- return $ss->but(next_step => $step);
- }
- return $ss->but(next_step => DX::Step::Backtrack->new);
+ trace consider => [
+ statement => [
+ [ symbol => 'consider' ],
+ @{$self->proposition->for_deparse->[1]},
+ ],
+ ];
+ my $old_scope = (my $old_hyp = $ss->current_hypothesis)->scope;
+ my @old_locals = @{$old_scope->locals};
+ my $top_level = $#old_locals;
+ my $top = pop @old_locals;
+ my $top_members = $top->members;
+ my @new_names = grep !exists $top_members->{$_},
+ keys %{$self->proposition->introduced_names};
+ my $new_scope = $old_scope->but(
+ locals => [
+ @old_locals,
+ $top->but(members => {
+ %{$top_members},
+ map +($_ => DX::Value::Unset->new(
+ action_builder => DX::ActionBuilder::UnsetValue->new(
+ target_path => [ $top_level, $_ ],
+ )
+ )
+ ), @new_names
+ }),
+ ],
+ lex_map => {
+ %{$old_scope->lex_map},
+ map +($_ => [ $top_level, $_ ]), @new_names
+ }
+ );
+ my $new_hyp = $old_hyp->but(scope => $new_scope);
+ return $ss->but(
+ current_hypothesis => $new_hyp,
+ next_step => $self->proposition->resolve_for($new_scope)
+ );
}
1;