epsilon.core Module

The core module provides fundamental functionality for functional programming in Common Lisp.

Package Groups

Data Structures

Immutable, functional data structures with structural sharing:

• epsilon.lib.map - Hash Array Mapped Trie implementation
• epsilon.lib.sequence - Lazy sequences with memoization
• epsilon.lib.vector - Vector operations and utilities
• epsilon.lib.set - Immutable sets based on HAMT
• epsilon.lib.list - Extended list operations

Data Encoding

Serialization and parsing for common data formats:

• epsilon.lib.json - JSON encoding and decoding
• epsilon.lib.yaml - YAML document processing
• epsilon.lib.msgpack - Binary MessagePack serialization
• epsilon.lib.base64 - Base64 encoding
• epsilon.lib.hex - Hexadecimal conversion

Cryptography

Hashing and checksum algorithms:

• epsilon.lib.digest - SHA-2 cryptographic hashing
• epsilon.lib.checksum - CRC-32 and Adler-32 checksums

String Processing

Unicode-aware text manipulation:

• epsilon.lib.string - String processing utilities
• epsilon.lib.char - Character operations
• epsilon.lib.regex - Regular expression matching

System

Platform integration and system services:

• epsilon.sys.fs - Filesystem operations
• epsilon.sys.thread - Threading primitives and pools
• epsilon.sys.env - Environment variable access

Tools

Development and build utilities:

• epsilon.tool.build - Dependency-tracking build system
• epsilon.tool.test - Test framework with metrics
• epsilon.tool.benchmark - Performance measurement

Design Principles

All packages in epsilon.core follow these principles:

• Immutability: Data structures don't modify in place
• Functional interfaces: Pure functions where possible
• Structural sharing: Efficient memory usage through shared structure
• Local nicknames: Clean integration with user code
• No dependencies: Built only on SBCL primitives

Common Patterns

;; Local nicknames for clean syntax
(defpackage :my-app
  (:use :cl)
  (:local-nicknames
   (:map :epsilon.lib.map)
   (:seq :epsilon.lib.sequence)
   (:json :epsilon.lib.json)))

;; Functional data manipulation
(-> (map:make-map :users '("alice" "bob"))
    (map:assoc :timestamp (get-universal-time))
    (json:encode))