Key Differences - T# versus C#

This page lists everything that is currently not supported in T#

While T# is designed to feel instantly familiar to Unity C# developers, there are a few important differences to keep in mind. These tweaks exist to support the interpreted nature of T# and ensure smoother live editing inside Terra Studio.

Most of your Unity habits will carry over just fine — but for the few edge cases, here's what you need to adjust:

🧾 1. Syntax Differences

T# follows Unity C# syntax closely, but some common programming patterns and language constructs are not supported due to the interpreted runtime. ✅ Supported: Start(), Update(), typed variables ❌ Not Supported: foreach, switch, enum, inline variable assignment, SerializeField, generics (GetComponent<T>()), etc.

➡️ See Full Syntax Differences in the link below →

Syntax Differences - T# v/s C#

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🌐 2. Multiplayer Scripting

T# uses a different base class for networked behavior. Unity's NetworkBehaviour is replaced by TerraNetBehaviour in T#, and includes its own override methods like OnNetworkSpawn() and OnNetworkDespawn() for multiplayer object lifecycle management.

➡️ See Multiplayer Differences documentation here→

Multiplayer Support Differences

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🔌 3. Unity API Restrictions

Certain Unity MonoBehaviour APIs are not available in T#, especially those involving advanced lifecycle hooks or reflection.

• ❌ Not Supported: LateUpdate(), Invoke(), TryGetComponent(), GetComponent<T>(), OnCollisionEnter as coroutine, Start() as coroutine, and more.

• ✔️ Workaround: Use coroutines manually (StartCoroutine()) and simulate delayed behavior with WaitForSeconds() or WaitForEndOfFrame().

➡️ See Unity API Restrictions here →

Restrictions on Unity APIs

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🧱 4. Restrictions on Collections & Types

T# does not support C# generics-based collections like List<T>, Dictionary<TKey, TValue>, or LINQ queries. Instead, use Terra-compatible containers:

• ✅ TerraList

• ✅ TerraDictionary

• ❌ Avoid: storing custom scripts or structs in collections

➡️ See Collections & Types restrictions here→

Restrictions on Collections & Types

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🎮 5. Input, UI & Miscellaneous Restrictions

Unity-specific interfaces like IPointerClickHandler, Action with more than 4 parameters, and try-catch blocks are unsupported in T#. Manual input handling and structured coroutines are your go-to alternatives. Also:

• ❌ Vector3 boxing

• ❌ partial classes

• ✅ PlayerPrefs is fully supported (and integrated with Analytics)

➡️ See Input, UI & Misc Limitations →

Restrictions on Input, UI, Async