Strify

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Not LexToString, not JSON — compile-time debug stringify for UE containers and pointers.

Unreal Engine plugin that converts values to FString via UStrify::ToString. Overload selection is compile-time (SFINAE / if constexpr). Types can opt in with a ToString() member.

Requirements

• Unreal Engine 5.6+

Install

1. Copy Plugins/Strify into your project's Plugins directory.
2. Enable the plugin in the .uproject:

"Plugins": [
  { "Name": "Strify", "Enabled": true }
]

3. Add the module to any Build.cs that includes the headers:

PublicDependencyModuleNames.Add("Strify");

This repository is a UE 5.6 sample project (StrifyTest) that already contains the plugin.

Usage

#include "Strify.h"

FString IntStr = UStrify::ToString(42);

TArray<int32> Numbers = {1, 2, 3};
FString ArrayStr = UStrify::ToString(Numbers);        // [1, 2, 3]
FString Multiline = UStrify::ToString(Numbers, true); // [\n1,\n2,\n3\n]

UE_LOG(LogTemp, Display, TEXT("%s"), *ArrayStr);

Logging TMap<uint64, TSet<int32>>:

// Before
UE_LOG(LogTemp, Display, TEXT("IdToValues: %s"), *FString::JoinBy(IdToValues, TEXT(","), [](const TPair<uint64, TSet<int32>>& Pair) {
    return FString::Printf(TEXT("{%llu:[%s]}"), Pair.Key, *FString::JoinBy(Pair.Value, TEXT(","), [](int32 Value) {
        return FString::Printf(TEXT("%d"), Value);
    }));
}));

// After — second arg is Multilines
UE_LOG(LogTemp, Display, TEXT("IdToValues: %s"), *UStrify::ToString(IdToValues, true));

• Less to type.
• The map used to be TMap<uint64, TArray<int32>>, then became TMap<uint64, TSet<int32>>. Nested FString::JoinBy lambdas must change parameter types; UStrify::ToString does not.

Add FString ToString() const on a struct or UObject subclass; THasToStringFunc detects it:

struct FMyStruct
{
    int32 Value1;
    float Value2;

    FString ToString() const
    {
        return FString::Printf(TEXT("MyStruct(%d,%f)"), Value1, Value2);
    }
};

Supported types

Kind	Result
Integers	Decimal
Floating point	Three decimal places (%.3f)
bool	true / false
FString	Unchanged
UENUM enum class	Reflection name
TEnumAsByte<T>	UEnum::GetValueAsString
Other enums	TypeName(underlying)
Types with ToString()	That member
UObject without ToString()	<unsupported {ClassName}: {GetName()}>
Raw, shared, unique, weak, and object pointers	Recurse if valid; "" if null or stale
FVariant	Routed by stored type; unknown → <unsupported variant: EVariantTypes(N)>
TArray	[a, b, c]
TSet	(a, b, c)
TMap	{key: value, ...}
Byte buffers	UStrify::ToHexString — uppercase hex, no separators

Empty containers stringify to "". Null or empty elements inside a container keep a slot ([1, , 3]). Nested containers recurse.

Type traits

TypeTraits.h:

• TIsContainer<T> — begin(), end(), and IsEmpty()
• THasToStringFunc<T> — FString ToString() (via DECLARE_HASFUNCTION_TYPETRAITS)
• Strify::GetTypeName<T>() — compiler signature (__FUNCSIG__ / __PRETTY_FUNCTION__), no UE reflection

static_assert(TIsContainer<TArray<int32>>::Value);
static_assert(!TIsContainer<int32>::Value);

Tests

Editor automation specs are in Plugins/Strify/Source/Strify/Private/Tests (Strify.UnitTests).

License

MIT. When used with Unreal Engine, the Epic Games Unreal Engine EULA still applies.