diff --git a/ASTPlayground/ASTPlayground.dproj b/ASTPlayground/ASTPlayground.dproj
index e961501..2eeac5b 100644
--- a/ASTPlayground/ASTPlayground.dproj
+++ b/ASTPlayground/ASTPlayground.dproj
@@ -4,7 +4,7 @@
         <ProjectVersion>20.3</ProjectVersion>
         <FrameworkType>FMX</FrameworkType>
         <Base>True</Base>
-        <Config Condition="'$(Config)'==''">Release</Config>
+        <Config Condition="'$(Config)'==''">Debug</Config>
         <Platform Condition="'$(Platform)'==''">Win64</Platform>
         <ProjectName Condition="'$(ProjectName)'==''">ASTPlayground</ProjectName>
         <TargetedPlatforms>2</TargetedPlatforms>
diff --git a/Src/AST/Myc.Ast.RTL.Core.pas b/Src/AST/Myc.Ast.RTL.Core.pas
index 5cf4019..d5ddd28 100644
--- a/Src/AST/Myc.Ast.RTL.Core.pas
+++ b/Src/AST/Myc.Ast.RTL.Core.pas
@@ -16,19 +16,19 @@ type
     TRtlFunctions = record
     public
         [TRtlFunction('Abs')]
-        class function Abs(Arg: TScalar): TScalar; static;
+        class function Abs(const Arg: TScalar): TScalar; static;
 
         [TRtlFunction('Trunc')]
-        class function Trunc(Arg: TScalar): TScalar; static;
+        class function Trunc(const Arg: TScalar): TScalar; static;
 
         [TRtlFunction('Ceil')]
-        class function Ceil(Arg: TScalar): TScalar; static;
+        class function Ceil(const Arg: TScalar): TScalar; static;
 
         [TRtlFunction('Floor')]
-        class function Floor(Arg: TScalar): TScalar; static;
+        class function Floor(const Arg: TScalar): TScalar; static;
 
         [TRtlFunction('Sign')]
-        class function Sign(Arg: TScalar): TScalar; static;
+        class function Sign(const Arg: TScalar): TScalar; static;
 
         // NOTE: Higher-order and complex functions can keep the TDataValue signature for now.
         // The registry is smart enough to handle both native types and the TDataValue signature directly.
@@ -56,7 +56,7 @@ uses
     System.Math,
     Myc.Data.Decimal;
 
-class function TRtlFunctions.Abs(Arg: TScalar): TScalar;
+class function TRtlFunctions.Abs(const Arg: TScalar): TScalar;
 begin
     case Arg.Kind of
         skInteger: Result := TScalar.FromInteger(System.Abs(Arg.Value.AsInteger));
@@ -70,7 +70,7 @@ begin
     end;
 end;
 
-class function TRtlFunctions.Trunc(Arg: TScalar): TScalar;
+class function TRtlFunctions.Trunc(const Arg: TScalar): TScalar;
 begin
     case Arg.Kind of
         skInteger, skInt64: Result := Arg; // Trunc on an integer is a no-op
@@ -82,7 +82,7 @@ begin
     end;
 end;
 
-class function TRtlFunctions.Ceil(Arg: TScalar): TScalar;
+class function TRtlFunctions.Ceil(const Arg: TScalar): TScalar;
 begin
     case Arg.Kind of
         skInteger, skInt64: Result := Arg; // Ceil on an integer is a no-op
@@ -94,7 +94,7 @@ begin
     end;
 end;
 
-class function TRtlFunctions.Floor(Arg: TScalar): TScalar;
+class function TRtlFunctions.Floor(const Arg: TScalar): TScalar;
 begin
     case Arg.Kind of
         skInteger, skInt64: Result := Arg; // Floor on an integer is a no-op
@@ -106,7 +106,7 @@ begin
     end;
 end;
 
-class function TRtlFunctions.Sign(Arg: TScalar): TScalar;
+class function TRtlFunctions.Sign(const Arg: TScalar): TScalar;
 begin
     case Arg.Kind of
         skInteger: Result := TScalar.FromInteger(System.Math.Sign(Arg.Value.AsInteger));