ReplFunction

Kind: Class

Source: packages/core/repl/repl-function.ts

Part of: Core

ReplFunction represents an executable function exposed through the core REPL system. It provides the action implementation through action() and generates user-facing command documentation through makeHelpMessage().

Methods

Properties

Diagram

mermaid
graph LR
  User[REPL User] --> Parser[REPL Command Parser]
  Parser --> Function[ReplFunction]
  Function --> Help[makeHelpMessage()]
  Function --> Action[action()]
  Action --> Result[ActionReturn]
  Result --> User

Usage

ts
import { ReplFunction } from "@core/repl/repl-function";

function runReplFunction(replFunction: ReplFunction) {
  // Display help when the function is requested without valid input.
  console.log(replFunction.makeHelpMessage());

  // Execute the function through the REPL runtime.
  const result = replFunction.action();

  return result;
}

AI Coding Instructions

• Keep command execution logic inside action() and return the expected ActionReturn value for the REPL runtime.
• Use makeHelpMessage() to provide concise, user-facing guidance for the function's syntax and behavior.
• Avoid writing directly to the console from action() unless the surrounding REPL conventions require it; prefer returning structured output.
• Ensure new REPL functions are registered through the relevant REPL command/function integration point.
• Keep help text aligned with the arguments and behavior implemented by action().

How it works

ReplFunction

ReplFunction is an abstract base class for a REPL-native function. It is generic over the argument tuple accepted by action and its return type; both default to Array<unknown> and any, respectively. [repl-function.ts:6-9]

A subclass must define:

• fnDefinition, containing a function name, description, and signature; it may also declare aliases. The interface documents name as a valid JavaScript function name and describes signature as TypeScript function-type-expression syntax. [repl-function.ts:10-11] [repl.interfaces.ts:4-19]
• action(...args), the abstract method called for function invocation from the REPL. [repl-function.ts:19-22]

The constructor receives a ReplContext, stores it as a protected read-only ctx, and assigns ctx.logger to a protected read-only logger. [repl-function.ts:13-17] Built-in subclasses access ctx for application operations and output; for example, GetReplFn.action calls ctx.app.get, while DebugReplFn writes through ctx.writeToStdout and reports a missing module through logger.error. [native-functions/get-repl-fn.ts:14-16] [native-functions/debug-repl-fn.ts:15-36]

Relationships

• IMPORTS → Logger