Refine single-value column to treat it as that single value (#12120)

- First experiments with intersection types as refinements to our Table/Column
- Closes #12095

distribution/lib/Standard/Base/0.0.0-dev/src/Data/Dictionary.enso

@@ -174,9 +174,9 @@ type Dictionary key value
     insert self key=(Missing_Argument.throw "key") value=(Missing_Argument.throw "value") no_warning:Boolean=False =
         new_dict = self.insert_builtin key value
         case key of
-            _ : Float ->
+            key_as_float : Float ->
                 if no_warning then new_dict else
-                    Warning.attach (Floating_Point_Equality.Used_As_Dictionary_Key key) new_dict
+                    Warning.attach (Floating_Point_Equality.Used_As_Dictionary_Key key_as_float) new_dict
             _ -> new_dict
 
     ## GROUP Selections

distribution/lib/Standard/Table/0.0.0-dev/src/Column.enso

@@ -38,6 +38,7 @@ from project.Errors import Conversion_Failure, Inexact_Type_Coercion, Invalid_Co
 from project.Internal.Column_Format import all
 from project.Internal.Java_Exports import make_string_builder
 from project.Internal.Storage import enso_to_java, java_to_enso
+from project.Internal.Type_Refinements.Single_Value_Column import refine_with_single_value
 
 polyglot java import org.enso.base.Time_Utils
 polyglot java import org.enso.table.data.column.operation.cast.CastProblemAggregator
@@ -87,7 +88,7 @@ type Column
              example_from_vector =
                  Column.from_vector "My Column" [1, 2, 3, 4, 5]
     from_vector : Text -> Vector -> Auto | Value_Type -> Column ! Invalid_Value_Type
-    from_vector (name : Text) (items : Vector) (value_type : Auto | Value_Type = Auto) =
+    from_vector (name : Text) (items : Vector) (value_type : Auto | Value_Type = Auto) -> Column =
         ## If the type does not accept date-time-like values, we can skip the
            additional logic for polyglot conversions that would normally be used,
            which is quite costly - so if we can guarantee it is unnecessary,
@@ -120,10 +121,12 @@ type Column
                 case needs_polyglot_conversion of
                     True -> Java_Column.fromItems name (enso_to_java_maybe items) expected_storage_type java_problem_aggregator
                     False -> Java_Column.fromItemsNoDateConversion name items expected_storage_type java_problem_aggregator
-            result = Column.from_java_column java_column . throw_on_warning Conversion_Failure
-            result.catch Conversion_Failure error->
-                if error.example_values.is_empty then result else
-                    raise_invalid_value_type_error error.example_values.first
+            multi_result = Column.from_java_column java_column
+            result = Warning.throw_on_warning multi_result Conversion_Failure
+            if Meta.is_error result . not then result else
+                result.catch Conversion_Failure error->
+                    if error.example_values.is_empty then result else
+                        raise_invalid_value_type_error error.example_values.first
 
     ## PRIVATE
        Creates a new column given a name and an internal Java storage.
@@ -135,9 +138,9 @@ type Column
 
     ## PRIVATE
        Creates a new column given a Java Column object.
-    from_java_column : Java_Column -> Column
-    from_java_column java_column =
-        Column.Value java_column
+    from_java_column java_column:Java_Column -> Column =
+        column = Column.Value java_column
+        column |> refine_with_single_value
 
     ## PRIVATE
        ADVANCED
@@ -1202,8 +1205,8 @@ type Column
                 storage_type = Storage.from_value_type_strict common_type
                 new_storage = Java_Problems.with_problem_aggregator Problem_Behavior.Report_Warning java_problem_aggregator->
                     case default of
-                        Column.Value java_col ->
-                            other_storage = java_col.getStorage
+                        col : Column ->
+                            other_storage = col.java_column.getStorage
                             storage.fillMissingFrom other_storage storage_type java_problem_aggregator
                         _ ->
                             storage.fillMissing default storage_type java_problem_aggregator
@@ -2699,9 +2702,9 @@ run_vectorized_binary_op column name operand new_name=Nothing fallback_fn=Nothin
     Java_Problems.with_map_operation_problem_aggregator column.name Problem_Behavior.Report_Warning problem_builder->
         storage_type = resolve_storage_type expected_result_type
         case operand of
-            Column.Value col2 ->
+            operand_column : Column ->
                 s1 = column.java_column.getStorage
-                s2 = col2.getStorage
+                s2 = operand_column.java_column.getStorage
                 rs = Polyglot_Helpers.handle_polyglot_dataflow_errors <|
                     s1.vectorizedOrFallbackZip name problem_builder fallback_fn s2 skip_nulls storage_type
                 Column.from_storage effective_new_name rs
@@ -2792,9 +2795,9 @@ run_vectorized_binary_op_with_fallback_problem_handling column name operand fall
             _ -> fallback_fn problem_builder
         storage_type = resolve_storage_type expected_result_type
         case operand of
-            Column.Value col2 ->
+            operand_column : Column ->
                 s1 = column.java_column.getStorage
-                s2 = col2.getStorage
+                s2 = operand_column.java_column.getStorage
                 rs = Polyglot_Helpers.handle_polyglot_dataflow_errors <|
                     s1.vectorizedOrFallbackZip name problem_builder applied_fn s2 skip_nulls storage_type
                 Column.from_storage new_name rs

distribution/lib/Standard/Table/0.0.0-dev/src/Internal/Type_Refinements/Single_Value_Column.enso

@@ -0,0 +1,34 @@
+private
+
+from Standard.Base import all
+
+import project.Column.Column
+import project.Value_Type.Value_Type
+from project.Internal.Type_Refinements.Single_Value_Column_Extensions import all
+
+refine_with_single_value (column : Column) =
+    ## We treat a column as single value if it contains a single not-nothing value.
+    if is_single_value column . not then column else case column.inferred_precise_value_type of
+        Value_Type.Integer _ ->
+            # `inferred_precise_value_type` will return Integer if the column was Float (or Mixed) but contained integral values - e.g. [2.0]
+            # We inspect the actual value to correctly deal with both Float and Mixed base type.
+            value = column.at 0
+            case value of
+                # If the value was really a float, we preserve that.
+                _ : Float -> (column : Column & Float)
+                # Otherwise we treat it as an integer.
+                _ -> (column : Column & Integer)
+        Value_Type.Float _ -> (column : Column & Float)
+        Value_Type.Char _ _ -> (column : Column & Text)
+        Value_Type.Boolean -> (column : Column & Boolean)
+        Value_Type.Date -> (column : Column & Date)
+        Value_Type.Time -> (column : Column & Time_Of_Day)
+        Value_Type.Date_Time True -> (column : Column & Date_Time)
+        Value_Type.Decimal _ scale ->
+            is_integer = scale == 0
+            if is_integer then (column : Column & Integer) else (column : Column & Decimal)
+        # Other types (e.g. Mixed) are not supported.
+        _ -> column
+
+is_single_value column:Column -> Boolean =
+    (column.length == 1) && (column.at 0 . is_nothing . not)

distribution/lib/Standard/Table/0.0.0-dev/src/Internal/Type_Refinements/Single_Value_Column_Extensions.enso

@@ -0,0 +1,51 @@
+private
+
+from Standard.Base import all
+
+import project.Column.Column
+from project.Internal.Type_Refinements.Single_Value_Column import is_single_value
+
+## This conversion is internal and should never be exported.
+Integer.from (that : Column) -> Integer =
+    Runtime.assert (is_single_value that)
+    x = that.at 0
+    case x of
+        _ : Integer -> x
+        _ : Float ->
+            Runtime.assert (x % 1.0 == 0.0)
+            x.truncate
+
+## This conversion is internal and should never be exported.
+Float.from (that : Column) -> Float =
+    Runtime.assert (is_single_value that)
+    that.at 0
+
+## This conversion is internal and should never be exported.
+Text.from (that : Column) -> Text =
+    Runtime.assert (is_single_value that)
+    that.at 0
+
+## This conversion is internal and should never be exported.
+Boolean.from (that : Column) -> Boolean =
+    Runtime.assert (is_single_value that)
+    that.at 0
+
+## This conversion is internal and should never be exported.
+Date.from (that : Column) -> Date =
+    Runtime.assert (is_single_value that)
+    that.at 0
+
+## This conversion is internal and should never be exported.
+Time_Of_Day.from (that : Column) -> Time_Of_Day =
+    Runtime.assert (is_single_value that)
+    that.at 0
+
+## This conversion is internal and should never be exported.
+Date_Time.from (that : Column) -> Date_Time =
+    Runtime.assert (is_single_value that)
+    that.at 0
+
+## This conversion is internal and should never be exported.
+Decimal.from (that : Column) -> Decimal =
+    Runtime.assert (is_single_value that)
+    that.at 0

distribution/lib/Standard/Table/0.0.0-dev/src/Table.enso

@@ -144,13 +144,13 @@ type Table
     new : Vector (Vector | Column) -> Table
     new columns =
         invalid_input_shape =
-            Error.throw (Illegal_Argument.Error "Each column must be represented by a pair whose first element is the column name and the second element is a vector of elements that will constitute that column, or an existing column.")
+            Error.throw (Illegal_Argument.Error "Each column must be represented by a pair whose first element is the column name and the second element is a vector of elements that will constitute that column, or an existing column. Got: "+columns.to_text)
         cols = columns.map on_problems=No_Wrap.Value c->
             case c of
                 v : Vector ->
                     if v.length != 2 then invalid_input_shape else
                         Column.from_vector (v.at 0) (v.at 1) . java_column
-                Column.Value java_col -> java_col
+                col : Column -> col.java_column
                 _ -> invalid_input_shape
         Panic.recover Illegal_Argument <|
             if cols.is_empty then
@@ -2472,9 +2472,9 @@ type Table
         unique.mark_used self.column_names
 
         resolved = case value of
+            _ : Column -> value
             _ : Text -> self.make_constant_column value
             _ : Expression -> self.evaluate_expression value on_problems
-            _ : Column -> value
             _ : Constant_Column -> self.make_constant_column value.value
             _ : Simple_Expression -> value.evaluate self (set_mode==Set_Mode.Update && as=="") on_problems
             _ -> Error.throw (Illegal_Argument.Error "Unsupported type for `Table.set`.")

engine/runtime/src/main/java/org/enso/interpreter/node/typecheck/AllOfTypesCheckNode.java

@@ -9,18 +9,18 @@
 import org.enso.interpreter.runtime.EnsoContext;
 import org.enso.interpreter.runtime.data.EnsoMultiValue;
 import org.enso.interpreter.runtime.data.Type;
-import org.enso.interpreter.runtime.library.dispatch.TypesLibrary;
+import org.enso.interpreter.runtime.library.dispatch.TypeOfNode;
 
 final class AllOfTypesCheckNode extends AbstractTypeCheckNode {
 
   @Children private AbstractTypeCheckNode[] checks;
-  @Child private TypesLibrary types;
+  @Child private TypeOfNode typeNode;
   @Child private EnsoMultiValue.NewNode newNode;
 
   AllOfTypesCheckNode(String name, AbstractTypeCheckNode[] checks) {
     super(name);
     this.checks = checks;
-    this.types = TypesLibrary.getFactory().createDispatched(checks.length);
+    this.typeNode = TypeOfNode.create();
     this.newNode = EnsoMultiValue.NewNode.create();
   }
 
@@ -46,7 +46,8 @@ Object executeCheckOrConversion(VirtualFrame frame, Object value, ExpressionNode
       if (result == null) {
         return null;
       }
-      var t = types.getType(result);
+      var t = typeNode.findTypeOrNull(result);
+      assert t != null : "Value " + result + " doesn't have type!";
       var ctx = EnsoContext.get(this);
       if (ctx.getBuiltins().number().getInteger() == t) {
         if (++integers > 1) {

engine/runtime/src/main/java/org/enso/interpreter/runtime/data/EnsoMultiType.java

@@ -26,9 +26,19 @@ final class EnsoMultiType {
   private final Type[] types;
 
   private EnsoMultiType(Type[] types) {
+    assert checkNonNull(types);
     this.types = types;
   }
 
+  private static boolean checkNonNull(Type[] types) {
+    for (var t : types) {
+      if (t == null) {
+        return false;
+      }
+    }
+    return true;
+  }
+
   @CompilerDirectives.TruffleBoundary
   static EnsoMultiType findOrCreateSlow(Type[] types, int from, int to) {
     var mt = new EnsoMultiType(Arrays.copyOfRange(types, from, to));

engine/runtime/src/main/java/org/enso/interpreter/runtime/data/EnsoMultiValue.java

@@ -506,7 +506,9 @@ Object invokeMember(
   @Override
   public String toString() {
     var both = EnsoMultiType.AllTypesWith.getUncached().executeAllTypes(dispatch, extra, 0);
-    return Stream.of(both).map(t -> t.getName()).collect(Collectors.joining(" & "));
+    return Stream.of(both)
+        .map(t -> t != null ? t.getName() : "[?]")
+        .collect(Collectors.joining(" & "));
   }
 
   /** Casts {@link EnsoMultiValue} to requested type effectively. */

test/Table_Tests/src/In_Memory/Main.enso

@@ -12,6 +12,7 @@ import project.In_Memory.Fan_Out_Spec
 import project.In_Memory.Integer_Overflow_Spec
 import project.In_Memory.Lossy_Conversions_Spec
 import project.In_Memory.Parse_To_Table_Spec
+import project.In_Memory.Single_Value_Column_Spec
 import project.In_Memory.Split_Tokenize_Spec
 import project.In_Memory.Table_Spec
 import project.In_Memory.Table_Xml_Spec
@@ -33,6 +34,7 @@ add_specs suite_builder =
     Integer_Overflow_Spec.add_specs suite_builder
     Lossy_Conversions_Spec.add_specs suite_builder
     Parse_To_Table_Spec.add_specs suite_builder
+    Single_Value_Column_Spec.add_specs suite_builder
     Split_Tokenize_Spec.add_specs suite_builder
     Table_Conversion_Spec.add_specs suite_builder
     Table_Date_Spec.add_specs suite_builder