Common Lisp Recipes

Common Lisp Recipes is a collection of solutions to problems and answers to questions you are likely to encounter when writing real-world applications in Common Lisp. Written by an author who has used Common Lisp in many successful commercial projects over more than a decade, this book is the first Common Lisp Recipes: A Problem-Solution ApproachEdmund weitzHamburg germanyISBN13(pbk):978-1-4842-1177-9ISBN-13( electronic:978-1-4842-1176-2DOI:10.1007/978-1-4842-1176-2Library of Congress Control Number: 2015960959Copyright o 2016 by Edmund WeitzThis work is subject to copyright. 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For more information, reference our Special bulkSales-ebookLicensingwebpageatwww.apress.com/bulk-salesAny source code or other supplementary materials referenced by the author in this text is available to readers atwww.apress.com/9781484211779.Fordetailedinformationabouthowtolocateyourbookssourcecodegotowww.apress.com/source-code/.ReaderscanalsoaccesssourcecodeatSpringerlinkintheSupplementaMaterial section for each chapterPrinted on acid-free paperwww.it-ebooks.infoFor heike and mounawww.it-ebooks.infoTable of contentsabout the authorXVILabout the Technical reviewerXⅨXPrefaceXXIWho This book is forXXIWho This Book Is(Probably)Not ForXX∏How to read This bookXXIIWhat's In and what not.,,,,,,,,,,,.XXTIThe hyperspecXXIVWhich ImplementationSource codeXXVThe IndexXXVTypographical conventionsXXVAcknowledgements1. Symbols and Packages1-1. Understanding the role of packages and the symbol nomenclature. 11-2. Making unique symbols1-3. Making Symbols InaccessibleHow Can We Fix This?1-4. Avoiding Name Conflicts12When Name Conflicts do Not occur151-5. Using Symbols as stand-Ins for Arbitrary forms151-6. Searching for Symbols by Name171-7. Iterating Through All Symbols of a Package19What To Do If You don t Like loop201-8. Understanding COMMON LISP's Case(In)Sensitivity21Style hint: Dont Use CamelCase!251-9. Using Symbols As String Substitutes26So, what Should You use?271-10."Overloading"of Standard COMMON LISP Operators282. Conses, Lists, and trees312-1. Understanding Conses31List ace34Testing Whether Something Is a Cons or a list3522. Creating Lists..·37Converting Vectors to Lists382-3. Transposing a Matrix39www.it-ebooks.infoTable of contents2-4. USing List Interpolation2-5. Adding Objects to the End of a List42The Tail Wagging the list442-6. Splicing" into a List452-7. Detecting Shared Structure in Lists49Isolating the Non-Shared Part512-8orking with Trees.51More Complicated Trees54COMMON LISP'S Standard Tree Functions552-9. Working with Stacks552-10. Implementing a queue562-11. Destructuring and Pattern Matching583. Strings and Characters..613-1. Getting the asCll Code of a characterThe Other Way around..,,63The limit633-2. Naming Characters633-3. USing Different Character Encodings653-4. Comparing strings or Characters.,.,67Internationalization703-5. Escaping Characters in String Literals and Variable InterpolationIs It still a literal?723-6. Controlling caseWhat about Unicode?743-7. Accessing or Modifying a Substring.753-8. Finding a Character or a Substring Within a String773-9. Trimming strings773-10. Processing a string one character at a time793-11. Joining Strings813-12. Reading csv Data4. Numbers and math874-1. USing Arbitrarily Large Integers....874-2. Understanding Fixnums894-3. Performing Modular Arithmetic92Efficiency Considerations4-4. Switching Bases944-5. Performing Exact Arithmetic with Rational numbers96Various Ways of Converting Numbers to IntegersHow Not to use floor and friendsConverting Floating-Point Numbers to Rationals and Vice Versa 99Mixing rationals and Floats....1014-6. Controlling the Default Float Format1024-7. Employing arbitrary precision Floats1044-8. Working with Complex numbers106www.it-ebooks.infoTable of contents4-9. Parsing numbers4-10. Testing Whether Two Numbers Are Equal.111Dont Ever use eQ with Numbers!1124-11. Computing Angles Correctly.1134-12. Calculating exact Square roots1155. Arrays and Vectors1175-1. Working with Multiple Dimensions1175-2. Understanding vectors and Simple arrays..,.1195-3. Obtaining the Size of an Array.1205-4. Providing Initial Contents121A Warning About Identical Objects122Treating Arrays As Vectors123Making the length of vectors Flexible1255-7. Adjusting arrays1275-8. USing an Array As a" Windowinto Another Array1295-9. Restricting the Element Type of an array.131Upgrading Element Types1335-10. Copying an array134A Warning About Object Identity1356. Hash Tables, maps, and sets1376-1. Understanding the Basics of Hash Tables137Why Does GETHASH Return Two values139How Many Entries does the hash Table have?1406-2. Providing Default Values For Hash Table Lookups1406-3. Removing Hash Table entries.1426-4. Iterating Through a Hash Table.143Dont rely on any order146Don't Modify While You're Iterating147Cant This be more concise, please?1476-5. Understanding hash Table Tests and defining your own148What Is sXhash For?1526-6. Controlling Hash Table growth1526-7. Getting Rid of Hash Table Entries Automatically.1556-8. Representing Maps As Association Lists158Combining Lookup and manipulation161Why Would Anybody Prefer Alists over Hash Tables? .... 1626-9. Representing Maps As Property Lists163When to Prefer plists over Alists165The plist of a Symbol1666-10. Working with Sets166Representing sets As hash Tables169Representing sets as Bit Patterns1697. Sequences and iteration.1717-1. Filtering a Sequence.....171www.it-ebooks.infoTable of contents7-2. Searching a Sequence.1727-3. Sorting and Merging Sequences1757-4. Mixing Different Sequence Types.1777-5. Re-USing a Part of a Sequence..1777-6. Repeating some values cyclically.179Alternatives,...1817-7. Counting down....1827-8. Iterating over" Chunks"of a List.1847-9. Closing over Iteration Variables1867-10."Extending" Short Sequences in Iterations1877-11. Breaking out of LOOP1887-12. Making sense of the MAP... ZoThe Sequence variants.1947-13. Defining Your Own Sequence Types....1947-14. Iterating with ITERATE1967-15. Iterating with SERIES200What the Example does2018. The Lisp reade2038-1. Employing the Lisp reader for Your Own Code203Why read Is potentially dangerous205What rEAD Doesnt Do205The Optional arguments to READ206Go Wild!2068-2. Troubleshooting Literal Object Notation.206This also Applies to Strings.2088-3. Evaluating Forms at Read Time208What to look out for210Alternatives..2108-4. Embedding literal arrays into Your Code.,,.211The Usual Warning.2128-5. Understanding the Different Ways to Refer to a Function....... 2138-6. Repeating Something You already Typed.,,214They Dont Only Look Identical, They Are Identical2168-7. Safely Experimenting with readtables.216Temporarily switching to Standard Io Syntax.2188-8. Changing the Syntax Type of a Character.,..219The Six Syntax Types220How to Actually Change the Syntax Type222Some Things Never Change2228-9. Creating Your Own Reader macros223What Reader macro functions do2248-10. Working with Dispatching Macro Characters2268-11. Preserving Whitespace228www.it-ebooks.infoTable of contentsIting2319-1. Using the printing primitives231Printing Objects So That They Can Be read Back in Again235Shortcuts2369-2. Printing to and into Strings2379-3. Printing NIL as a list2399-4. Extending FORMAT Control Strings Over More Than One line2409-5. USing Functions As FORMAT Controls2419-6. Creating Your Own FORMaT Directives.2439-7. Recursive Processing of FORMAT Controls2459-8. Controlling How Your Own Objects Are Printed.2479-9. Controlling the Pretty Printer2499-10. Printing Long lists2539-11. Pretty-Printing Compound objects257Using the Pretty printer from FORMAt2609-12. Modifying the Pretty Printer.26210. Evaluation, Compilation, Control Flow26510-1. Comparing Arbitrary Lisp Objects.265Comparing State26Constants26910-2. Using Constant Variables as Keys in CASE Macros26910-3. Using Arbitrary Variable Names for Keyword Parameters ..... 271Keyword Names Don t have to be Keywords272Keyword Dames Dont have to Be Constant27310-4. Creating"Static Local Variables, "Like in C27310-5.Preponing the Computation of values27510-6. Modifying the behavior of functions You dont Have the Source of 27810-7. Swapping the values of Variables(or Places10-8. Creating Your Own \rte Forms for"Phgt∵…280283Using DEFSETF285Using DEFINE-SETF-EXPANDER286So, Which one do i use?291Using DEFINE-MODIFY-MACRO.291Multiple-valued places29310-9. Working with Environments29410-10. Commenting Out Parts of Your CodeSome notes about and#302How; #I, and Others are lmplemented30211. Concurrency30311-1. Managing Lisp Processes.304Escape Hatches307Threads Are expensive3081-2. Accessing Shared Resources Concurrently.308Locks.312Xwww.it-ebooks.infoTable of contentsAtomic Operations.313More problems31411-3. Using Special Variables in Concurrent Programs.317Per-Thread Initial Bindings..319Variables That Are Always Globa...31911-4. Communicating with Other Threads320Alternatives11-5. Parallelizing Algorithms Without Threads and Locks322322What the Example does325Fine-Tuning326Trees326Alternatives33011-6. Determining the Number of Cores33012. Error Handling and Avoidance33312-1. Checking Types at Run Time333Alternatiⅴes33512-2. Adding assertions to Your Code336Disabling Assertions in"Production Code33812-3. Defining Your Own Conditions.,..338How Conditions are printed34012-4. Signaling a condition.341Condition designators34312-5. Handling Conditions344Ignoring errors.34912-6. Providing and Using Restarts350Visible restarts354Predefined restarts35512-7. Getting Rid of Warning Messages..35612-8. Protecting Code from Non-Local Exits357WITH-Macros.36013. Objects, Classes, Types36113-1. Defining Types.,..361Compound Type specifiers363Derived Types.36513-2. Using Classes As Types.36613-3. Writing Methods for Built-In Classes36713-4. Providing Constructors for Your Classes36913-5. Marking Slots As"Private37213-6. Changing the Argument Precedence Order..37413-7. Automatically Initializing Slots on First Usage..37613-8. Changing and Redefining Classes on the Fly377Objects Changing Their Class380Redefining CIasses38113-9. Making Your Objects Externalizable383www.it-ebooks.info