Soroban Env Subsystem (p26) — Technical Summary

Overview

The Soroban environment subsystem is split into two crates: soroban-env-common and soroban-env-host. Together they define the host-guest interface for Soroban smart contracts. soroban-env-common defines the ABI types and trait interfaces shared between guest (Wasm) and host code. soroban-env-host provides the concrete Host implementation that executes contracts, manages storage, budgets, authorization, events, and the Wasm VM.

The p26 host only supports protocol version 26 and later (MIN_LEDGER_PROTOCOL_VERSION = 26).

soroban-env-common

Val — The Universal 64-bit Value Type

Val (val.rs) is a 64-bit (u64) union type that is the fundamental ABI type crossing the host-guest boundary. It uses bit-packing:

• Low 8 bits: Tag enum indicating the type.
• Upper 56 bits: body, optionally subdivided into a 32-bit major and 24-bit minor.