Babysitter REPL Development

Expert skill for building interactive REPLs with rich editing and evaluation features

install

source · Clone the upstream repo

git clone https://github.com/a5c-ai/babysitter

Claude Code · Install into ~/.claude/skills/

T=$(mktemp -d) && git clone --depth=1 https://github.com/a5c-ai/babysitter "$T" && mkdir -p ~/.claude/skills && cp -r "$T/library/specializations/programming-languages/skills/repl-development" ~/.claude/skills/a5c-ai-babysitter-repl-development && rm -rf "$T"

manifest: library/specializations/programming-languages/skills/repl-development/SKILL.md

REPL Development Skill

Overview

Expert skill for building interactive REPLs with rich editing and evaluation features.

Capabilities

Implement readline integration with history
Handle multi-line input detection
Implement tab completion for identifiers
Design incremental compilation for REPL
Handle top-level expression evaluation
Implement persistent REPL state
Design pretty-printing for values
Support special REPL commands (:help, :type, etc.)

Target Processes

repl-development.js
interpreter-implementation.js
lsp-server-implementation.js

Dependencies

rustyline
readline libraries
linenoise

Usage Guidelines

Line Editing: Use established readline libraries for robust line editing
Multi-line: Detect incomplete expressions for multi-line input
Completion: Implement context-aware tab completion
History: Persist history across sessions
Commands: Provide useful meta-commands (:help, :type, :quit, etc.)

Output Schema

{
  "type": "object",
  "properties": {
    "lineLibrary": {
      "type": "string",
      "enum": ["readline", "rustyline", "linenoise", "custom"]
    },
    "features": {
      "type": "array",
      "items": { "type": "string" }
    },
    "commands": {
      "type": "array",
      "items": {
        "type": "object",
        "properties": {
          "name": { "type": "string" },
          "description": { "type": "string" }
        }
      }
    },
    "generatedFiles": {
      "type": "array",
      "items": { "type": "string" }
    }
  }
}