List of Listings

Chapter 1. Clojure philosophy

Listing 1.1. Function that solves math equations, evaluated right to left

Listing 1.2. Function that solves math equations, evaluated left to right

Listing 1.3. Function that changes evaluation order depending on operation weights

Listing 1.4. Polymorphic Concatenatable protocol

Listing 1.5. Simple chessboard representation in Clojure

Listing 1.6. Querying the squares of a chessboard

Listing 1.7. Using block-level encapsulation

Listing 1.8. Local encapsulation

Chapter 4. On scalars

Listing 4.1. Using a keyword as a function directive

Chapter 5. Collection types

Listing 5.1. Function for finding the neighbors of a spot on a 2D matrix

Listing 5.2. First cut of the position function

Listing 5.3. Final version of pos

Chapter 6. Being lazy and set in your ways

Listing 6.1. Short-circuiting if expression

Listing 6.2. Using lazy-seq to avoid stack overflows

Listing 6.3. Infinite sequences fostering declarative solutions

Listing 6.4. Lazy, tail-recursive, incremental quicksort

Chapter 7. Functional programming

Listing 7.1. Function to recursively convert units of measure

Listing 7.2. Using mutually recursive functions to implement a finite state machine

Listing 7.3. Function to estimate the straight-line remaining path cost

Listing 7.4. Function to calculate the cost of the path traversed so far

Listing 7.5. Function to calculate the estimated total cost of the path

Listing 7.6. Function to retrieve the minimum value based on a criteria function

Listing 7.7. Main A* algorithm

Listing 7.8. Running the A* algorithm on Z World

Listing 7.9. Shrubbery World

Listing 7.10. Bunny World

Chapter 8. Macros

Listing 8.1. Contract top-level macro

Listing 8.2. Contract auxiliary function build-contract

Listing 8.3. Composition of the contract function and constrained function

Listing 8.4. Contract for multiple-arity functions

Chapter 9. Combining data and code

Listing 9.1. Persistent binary tree built from records

Listing 9.2. Complete implementations of FIXO for TreeNode and vector

Listing 9.3. Using a map to extend FIXO to TreeNode

Listing 9.4. Size-limited stack FIXO using reify

Listing 9.5. Method implementations in defrecord

Listing 9.6. Implementing map interfaces with deftype

Chapter 10. Mutation and concurrency

Listing 10.1. 3 x 3 chess board representation using Clojure refs

Listing 10.2. Setting up the refs example

Listing 10.3. Using alter to update refs in a transaction

Listing 10.4. How to make a ref squirm

Listing 10.5. Controlling I/O with an agent

Listing 10.6. Resettable memoize function

Listing 10.7. Simple SafeArray protocol

Listing 10.8. Implementating SafeArray using the locking macro

Listing 10.9. Implementing SafeArray using ReentrantLock

Chapter 11. Parallelism

Listing 11.1. Converting an XML feed to an XML zipper

Listing 11.2. Normalizing RSS and Atom feed entries to a common structure

Listing 11.3. Retrieving the title text from the normalized feed structure

Listing 11.4. Function to count the number of occurrences of text

Listing 11.5. Manually spreading tasks over a sequence of futures

Listing 11.6. Macro to dispatch a sequence of futures

Listing 11.7. Counting text occurrences in feed titles fetched in parallel

Listing 11.8. Dispatching a sequence of promises across threads

Listing 11.9. Parallel test runner using with-promises

Listing 11.10. Transforming a callback-based function to a blocking call

Chapter 12. Java.next

Listing 12.1. Importing Java classes to create a simple, dynamic web server

Listing 12.2. Simplest possible web server using Java

Listing 12.3. Defining a default web handler using proxy

Listing 12.4. Web handler that echoes the request headers

Listing 12.5. “Around” filter that wraps an output stream with head and body tags

Listing 12.6. Quick and dirty function to generate HTML file listings

Listing 12.7. Function to build a string representation of a file-size listing

Listing 12.8. Function to convert a relative-path URI into a file

Listing 12.9. Web handler to list and navigate a local file system

Listing 12.10. DynaFrame class ns block showing rich gen-class usage

Listing 12.11. Simple GUI containers

Listing 12.12. Set of simple widgets

Listing 12.13. A more complex GUI example

Listing 12.14. java.util.List conformance for sequences and seqs

Listing 12.15. Interface defining a sliceable object

Listing 12.16. Dummy reified ISliceable

Listing 12.17. Using a protocol to extend ISliceable

Listing 12.18. Extending strings along the Sliceable protocol

Chapter 13. Why ClojureScript?

Listing 13.1. Extending ICounted to LinkedMap

Listing 13.2. Extending IFn to LinkedMap

Listing 13.3. Definition of the print-ast function

Listing 13.4. project.clj for music

Listing 13.5. HTML contents of music.html

Listing 13.6. Web Audio functions in ClojureScript

Listing 13.7. Tune-construction functions

Listing 13.8. Using analyze to generate an AST for a ClojureScript file

Listing 13.9. consecutive-notes function fixed to work in Clojure

Listing 13.10. notes function fixed to work in Clojure

Chapter 14. Data-oriented programming

Listing 14.1. Function to read distance units

Listing 14.2. Checking the form of an event

Listing 14.3. Event-sourcing function that affects state

Listing 14.4. Function that applies an effect only when the event is valid

Listing 14.5. Event-sourcing, mass-effect function

Listing 14.6. Data model for representing baseball player abilities

Listing 14.7. lookup function

Listing 14.8. Applying a baseball result event to a database

Listing 14.9. Transactionally applying result events to a data store

Listing 14.10. Generating a random baseball event based on player ability

Listing 14.11. Generating a number of random baseball events

Listing 14.12. Creating or retrieving a unique agent for a given player name

Listing 14.13. Feeding an event into the data store and player event store

Listing 14.14. Feeding all events into a data store and player event stores

Listing 14.15. Simulation driver

Listing 14.16. Driving the calculation of compositional units of measure

Listing 14.17. defunits-of macro

Chapter 15. Performance

Listing 15.1. Protocol for caching

Listing 15.2. BasicCache type

Listing 15.3. Type implementing pluggable memoization

Listing 15.4. Applying pluggable memoization to a function

Listing 15.5. Tail-recursive factorial, with no type declarations

Listing 15.6. Factorial with a coerced local

Listing 15.7. Factorial with a primitive long argument

Listing 15.8. Factorial without overflow checking

Listing 15.9. Factorial with a primitive double argument

Listing 15.10. Factorial with auto-promotion

Listing 15.11. Reimplementing Clojure’s range function using lazy-seq

Listing 15.12. Reimplementation of range that returns a reducible

Listing 15.13. Essence of mapping, bundled to be used with a reducible

Listing 15.14. Essence of filtering, bundled to be used with a reducible

Listing 15.15. Essence of mapcatting, bundled to be used with a reducible

Listing 15.16. A couple of reducible transformers

Listing 15.17. Converting transformers to core reducibles

Listing 15.18. Implementing a reducible-range via the CollReduce protocol

Listing 15.19. Converting transformers to core foldables

Chapter 16. Thinking programs

Listing 16.1. Printing the starting position of a Sudoku board

Listing 16.2. Brute-force Sudoku solver

Listing 16.3. Identifying logic variables

Listing 16.4. Simplified satisfiability function

Listing 16.5. Function that satisfies seqs

Listing 16.6. Walking a data structure and substituting logic variables for bound values

Listing 16.7. Melding two seqs, substituting logic variables

Listing 16.8. Querying planetary bodies

Listing 16.9. Recursively initializing a Sudoku board filled with logic variables

Listing 16.10. A core.logic Sudoku solver

Chapter 17. Clojure changes the way you think

Listing 17.1. select * example using Clojure’s relational algebra functions

Listing 17.2. Shuffling SQL-like operators into infix position

Listing 17.3. Looking up syntax processors in the processor table

Listing 17.4. Building a SQL-like SELECT statement DSL

Listing 17.5. Using with-redefs to create stubs

Listing 17.6. clojure.test as a partial specification

Listing 17.7. Creating formulas that are like spreadsheet cells

Listing 17.8. defformula to track baseball averages

Listing 17.9. Basis for an abstract factory implementation using multimethods

Listing 17.10. Defining concrete factories using multimethods

Listing 17.11. Protocols describing system-level and simulation capabilities

Listing 17.12. Using abstract system construction and a system-level protocol

Listing 17.13. Extending an existing type to the Sys and Sim protocols

Listing 17.14. Extending the existing HiFiSim type to Sys and Sim

Listing 17.15. Calculating both a low- and a high-fidelity answer

Listing 17.16. Creating a mock of a system

Listing 17.17. Extending a mock system to existing protocols.

Listing 17.18. Construction function for the mock system

Listing 17.19. Tying together a system via configuration

Listing 17.20. Injecting dependencies

Listing 17.21. Handling nefarious tree nodes with exceptions

Listing 17.22. Example of dynamic delegation

Listing 17.23. A modest debug console reader

Listing 17.24. Creating a map of the local context using &env

Listing 17.25. Implementation of a breakpoint macro

Listing 17.26. Using multiple breakpoints in the keys-apply function

Listing 17.27. Using a breakpoint in the awhen macro