LISPStudy Notes

Building a Simple Calculator in LISP

A hands-on walkthrough of building a working arithmetic expression calculator in Common Lisp, from tokenizing input to evaluating nested expressions.

Closures in LISP

How LISP closures bundle a function with its lexical environment to create private, persistent state, and common patterns and pitfalls that follow from it.

Code as Data: Homoiconicity

Why LISP source code and LISP data share the same list representation, and how this property enables macros, metaprogramming, and eval.

Conditionals in LISP

Master LISP's conditional forms — if, cond, when, unless, and case — for controlling program flow based on tested conditions.

Defining Functions in LISP

Learn how to define named functions in LISP using defun, understand parameter lists, return values, and documentation strings.

Dynamic vs Lexical Scope

How lexical scope resolves variables by source-text structure while dynamic scope resolves them by the call stack, and how Common Lisp uses both via special va…

Error Handling and Conditions

How Common Lisp's condition system goes beyond try/catch, letting programs signal, inspect, and interactively recover from errors using restarts.

File I/O in LISP

How Common Lisp reads and writes files using streams, with-open-file, and reader/printer control for both text and binary data.

Installing Common Lisp and the REPL

A practical guide to installing the SBCL Common Lisp implementation and getting comfortable working in the interactive REPL.

Lambda and Anonymous Functions

Learn how to create unnamed functions with lambda in LISP, and how they're used with higher-order functions like mapcar, remove-if, and reduce.

let and Local Bindings

Learn how let and let* create local variable bindings in LISP, and how their scoping rules differ from global assignment.

LISP Atoms and Data Types

A tour of LISP's core data types, numbers, symbols, strings, characters, and booleans, and how lists combine them into compound structures.

LISP Best Practices

Practical conventions for writing clean, maintainable LISP code, covering naming, recursion style, macro hygiene, and error handling.

LISP for AI and Symbolic Computing

Why LISP became the historical language of AI research, and how homoiconicity, symbolic data, and macros support symbolic reasoning, search, and rule-based sys…

LISP Interview Questions

Common LISP interview topics—from car/cdr fundamentals to macros and tail recursion—explained with the reasoning an interviewer expects.

LISP Quick Reference

A condensed cheat sheet of core LISP syntax, data structures, and special forms for Common Lisp, covering the operations used daily.

LISP Syntax and S-Expressions

How LISP's prefix-notation S-expressions work, the difference between atoms and lists, and how quoting controls evaluation.

LISP vs Modern Languages

A comparison of LISP's core design choices—homoiconicity, macros, and minimal syntax—against mainstream languages like Python, JavaScript, and Java.

List Manipulation Functions

The core built-in functions for navigating, searching, combining, and transforming lists, and the crucial distinction between destructive and non-destructive o…

Lists and Cons Cells

How Lisp builds every list out of two-slot cons cells, and how car, cdr, and quoting let you construct and inspect them.

Macros in LISP

How LISP macros transform unevaluated code at compile time to create new syntax, and how to write them safely with defmacro, gensym, and hygiene practices.

mapcar and Functional Iteration

How mapcar and its relatives let you transform lists by applying a function across them, without hand-writing explicit loops.

Quicklisp and Package Management

How Quicklisp and ASDF work together to define, load, and distribute Common Lisp systems and their dependencies.

quote and quasiquote

How LISP's quote, quasiquote, unquote, and unquote-splicing let you treat code as inert data and selectively rebuild it as templates.