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Version: v1.3

Call Context

Understanding the call context is vital in leveraging the Wasm code within a sandboxed host environment effectively. The following section explains the distinction between different function calls and the role of WasmLib in setting up a smart contract.

Function Calls: Func and View

Smart contract function calls come in two types, each having specific access levels to the smart contract state:

Funcs

Func functions grants full mutable access, resulting in a state update. They accommodate both on-ledger and off-ledger requests, finalized once the state update is registered in the Tangle ledger.

Views

View functions allow limited immutable access, no state update occurs. Views are ideal for quickly querying the contract's current state, they only facilitate off-ledger calls.

Using Func and View

WasmLib offers distinct contexts for these function types, namely ScFuncContext for Func and ScViewContext for View, controlling the accessible functionality and enforcing usage constraints through compile-time type-checking.

Smart Contract Setup with WasmLib

Setting up a smart contract requires the following:

Defining Funcs and Views

Outline available Funcs and Views and communicate them to the host through WasmLib. It ensures the correct dispatch of function calls and maintains necessary restrictions.

Parameter and Return Value Determination

Establish the parameters and return values for each function. ISC uses simple dictionaries to store details, necessitating consistent (de)serialization handled adeptly by WasmLib.

Utilizing Schema Tool

Although you can use the WasmLib directly, the Schema Tool is recommended for automatically generating and updating the smart contract framework in a type-safe manner, using the preferred language.

Grasping these concepts will facilitate a secure and efficient smart contract setup, steering clear of potential pitfalls while making the most of what WasmLib offers.