<EsHiredisPI> is the Platform Interface (PI) sub-application that provides the bridge to the native hiredis C library. Its role is twofold:

This layered approach encapsulates all low-level interaction, allowing the high-level <EsRedisApp> to remain agnostic of both the C implementation details and the underlying socket communication mechanism.

<EsHiredisSciSocketContext>: A pure Smalltalk object that manages the connection lifecycle. It uses an <SciSocket> for network I/O and orchestrates the sending of commands and the feeding of replies to the hiredis parser.

EsHiredisConstants: A pool dictionary that defines all necessary C constants from the hiredis.h header file, such as reply types (e.g., REDIS_REPLY_STRING) and connection flags (e.g., REDIS_CONNECTED).

EsHiredisPlatformFunctions: A pool dictionary that maps C functions from the hiredis library to Smalltalk PlatformFunction objects. This enables direct calls into the native library for functions like redisConnect, redisCommandArgv, and freeReplyObject.

<OSHiredisStructure> and its subclasses (notably <OSHiredisReader> and <OSHiredisReply>): A hierarchy of classes that provide a direct memory mapping to the C structs used by the hiredis parser. These are essential for receiving structured data back from the C library's parsing functions.

<EsHiredisCallEngine> and its subclasses: An abstraction that defines the strategy for how FFI calls are executed, supporting both direct synchronous calls and non-blocking asynchronous calls.