Scalar operators

Src/Data/Myc.Data.Scalar.pas

@@ -26,6 +26,9 @@ type
         skDecimal
     );
 
+    TBinaryOperator = (boAdd, boSubtract, boMultiply, boDivide, boEqual, boNotEqual, boLess, boGreater, boLessOrEqual, boGreaterOrEqual);
+    TUnaryOperator = (uoNegate, uoNot);
+
     TScalarBytes = array[0..7] of Byte;
     TScalarPChar = array[0..3] of Char;
     TScalarString = String[7];
@@ -94,11 +97,12 @@ type
 
         function ToString: String;
 
+        class function IsBinaryOperatorSupported(Op: TBinaryOperator; A, B: TScalarKind): Boolean; static;
+        class function IsUnaryOperatorSupported(Op: TUnaryOperator; A: TScalarKind): Boolean; static;
+
         class operator Add(const A, B: TScalar): TScalar;
         class operator Divide(const A, B: TScalar): TScalar;
         class operator Equal(const A, B: TScalar): Boolean;
-
-        //TODO implementieren
         class operator GreaterThan(const A, B: TScalar): Boolean;
         class operator GreaterThanOrEqual(const A, B: TScalar): Boolean;
         class operator LessThan(const A, B: TScalar): Boolean;
@@ -406,6 +410,65 @@ begin
     Result.Value := TScalarValue.FromUInt64(AValue);
 end;
 
+class function TScalar.IsBinaryOperatorSupported(Op: TBinaryOperator; A, B: TScalarKind): Boolean;
+begin
+    const FLOAT_KINDS: set of TScalarKind = [skSingle, skDouble];
+    const ORDINAL_KINDS: set of TScalarKind = [skInteger, skInt64, skUInt64];
+    const NUMERIC_KINDS: set of TScalarKind = FLOAT_KINDS + ORDINAL_KINDS + [skDecimal];
+    const COMPARABLE_KINDS: set of TScalarKind = NUMERIC_KINDS + [skDateTime, skChar, skString];
+
+    // General check for incompatible types
+    if (A = B) then
+    begin
+        case Op of
+            boAdd, boSubtract, boMultiply, boDivide: Result := A in NUMERIC_KINDS + [skDateTime];
+            boEqual, boNotEqual, boLess, boGreater, boLessOrEqual, boGreaterOrEqual: Result := A in COMPARABLE_KINDS;
+        else
+            Result := False;
+        end;
+    end
+    else
+    begin
+        // Mixed-type checks
+        case Op of
+            boAdd:
+                Result :=
+                    (((A in NUMERIC_KINDS) and (B in NUMERIC_KINDS))
+                        or ((A = skDateTime) and (B in ORDINAL_KINDS + FLOAT_KINDS))
+                        or ((B = skDateTime) and (A in ORDINAL_KINDS + FLOAT_KINDS)));
+            boSubtract:
+                Result := (((A in NUMERIC_KINDS) and (B in NUMERIC_KINDS)) or ((A = skDateTime) and (B in NUMERIC_KINDS + [skDateTime])));
+            boMultiply, boDivide: Result := (A in NUMERIC_KINDS) and (B in NUMERIC_KINDS);
+            boEqual, boNotEqual, boLess, boGreater, boLessOrEqual, boGreaterOrEqual:
+                Result := (A in NUMERIC_KINDS) and (B in NUMERIC_KINDS);
+        else
+            Result := False;
+        end;
+    end;
+
+    // Specific exclusion rules
+    if Result then
+    begin
+        // Decimal cannot be mixed with floats for any operator
+        if ((A = skDecimal) and (B in FLOAT_KINDS)) or ((B = skDecimal) and (A in FLOAT_KINDS)) then
+            Result :=
+                False
+                    // Cannot subtract a DateTime from a Numeric type
+        else if (Op = boSubtract) and (A in NUMERIC_KINDS) and (B = skDateTime) then
+            Result := False;
+    end;
+end;
+
+class function TScalar.IsUnaryOperatorSupported(Op: TUnaryOperator; A: TScalarKind): Boolean;
+begin
+    case Op of
+        uoNegate: Result := A in [skInteger, skInt64, skSingle, skDouble, skDecimal];
+        uoNot: Result := A in [skBoolean, skInteger, skInt64, skUInt64];
+    else
+        Result := False;
+    end;
+end;
+
 class function TScalar.StringToKind(const AName: string): TScalarKind;
 begin
     if SameText(AName, 'integer') then