null (CLCS)

0Home
1Introduction (Introduction)
- 1.1Scope
  - 1.1.1Scope and Purpose
  - 1.1.2History
- 1.2Organization of the Document
- 1.3Referenced Publications
- 1.4Definitions
  - 1.4.1Notational Conventions
    - 1.4.1.1Font Key
    - 1.4.1.2Modified BNF Syntax
      - 1.4.1.2.1Splicing in Modified BNF Syntax
      - 1.4.1.2.2Indirection in Modified BNF Syntax
      - 1.4.1.2.3Additional Uses for Indirect Definitions in Modified BNF Syntax
    - 1.4.1.3Special Symbols
    - 1.4.1.4Objects with Multiple Notations
      - 1.4.1.4.1Case in Symbols
      - 1.4.1.4.2Numbers (Objects with Multiple Notations)
      - 1.4.1.4.3Use of the Dot Character
      - 1.4.1.4.4nil (Meaning)
    - 1.4.1.12Designators
    - 1.4.1.13Nonsense Words
  - 1.4.2Error Terminology
  - 1.4.3Sections Not Formally Part Of This Standard
  - 1.4.4Interpreting Dictionary Entries
    - 1.4.4.1The "Affected By'' Section of a Dictionary Entry
    - 1.4.4.2The "Arguments'' Section of a Dictionary Entry
    - 1.4.4.3The "Arguments and Values'' Section of a Dictionary Entry
    - 1.4.4.4The "Binding Types Affected'' Section of a Dictionary Entry
    - 1.4.4.5The "Class Precedence List'' Section of a Dictionary Entry
    - 1.4.4.6Dictionary Entries for Type Specifiers
      - 1.4.4.6.1The "Compound Type Specifier Kind" Section of a Dictionary Entry
      - 1.4.4.6.2The "Compound Type Specifier Syntax" Section of a Dictionary Entry
      - 1.4.4.6.3The "Compound Type Specifier Arguments'' Section of a Dictionary Entry
      - 1.4.4.6.4The "Compound Type Specifier Description'' Section of a Dictionary Entry
    - 1.4.4.7The "Constant Value'' Section of a Dictionary Entry
    - 1.4.4.8The "Description'' Section of a Dictionary Entry
    - 1.4.4.9The "Examples'' Section of a Dictionary Entry
    - 1.4.4.10The "Exceptional Situations'' Section of a Dictionary Entry
    - 1.4.4.11The "Initial Value'' Section of a Dictionary Entry
    - 1.4.4.12The "Argument Precedence Order'' Section of a Dictionary Entry
    - 1.4.4.13The "Method Signature'' Section of a Dictionary Entry
    - 1.4.4.14The "Name'' Section of a Dictionary Entry
    - 1.4.4.15The "Notes'' Section of a Dictionary Entry
    - 1.4.4.16The "Pronunciation'' Section of a Dictionary Entry
    - 1.4.4.17The "See Also'' Section of a Dictionary Entry
    - 1.4.4.18The "Side Effects'' Section of a Dictionary Entry
    - 1.4.4.19The "Supertypes'' Section of a Dictionary Entry
    - 1.4.4.20The "Syntax'' Section of a Dictionary Entry
      - 1.4.4.20.1Special "Syntax'' Notations for Overloaded Operators
      - 1.4.4.20.2Naming Conventions for Rest Parameters
      - 1.4.4.20.3Requiring Non-Null Rest Parameters in the "Syntax'' Section
      - 1.4.4.20.4Return values in the "Syntax'' Section
      - 1.4.4.20.5No Arguments or Values in the "Syntax'' Section
      - 1.4.4.20.6Unconditional Transfer of Control in the "Syntax'' Section
    - 1.4.4.21The "Valid Context'' Section of a Dictionary Entry
    - 1.4.4.22The "Value Type'' Section of a Dictionary Entry
- 1.5Conformance
  - 1.5.1Conforming Implementations
    - 1.5.1.1Required Language Features
    - 1.5.1.2Documentation of Implementation-Dependent Features
    - 1.5.1.3Documentation of Extensions
    - 1.5.1.4Treatment of Exceptional Situations
    - 1.5.1.5Resolution of Apparent Conflicts in Exceptional Situations
    - 1.5.1.6Examples of Resolution of Apparent Conflict in Exceptional Situations
    - 1.5.1.7Conformance Statement
  - 1.5.2Conforming Programs
    - 1.5.2.1Use of Implementation-Defined Language Features
    - 1.5.2.2Use of Read-Time Conditionals
- 1.6Language Extensions
- 1.7Language Subsets
- 1.8Deprecated Language Features
  - 1.8.1Deprecated Functions
  - 1.8.2Deprecated Argument Conventions
  - 1.8.3Deprecated Variables
  - 1.8.4Deprecated Reader Syntax
- 1.9Symbols in the COMMON-LISP Package
2Syntax
- 2.1Character Syntax
  - 2.1.1Readtables
    - 2.1.1.1The Current Readtable
    - 2.1.1.2The Standard Readtable
    - 2.1.1.3The Initial Readtable
  - 2.1.2Variables that affect the Lisp Reader
  - 2.1.3Standard Characters
  - 2.1.4Character Syntax Types
    - 2.1.4.1Constituent Characters
    - 2.1.4.2Constituent Traits
    - 2.1.4.3Invalid Characters
    - 2.1.4.4Macro Characters
    - 2.1.4.5Multiple Escape Characters
    - 2.1.4.6Examples of Multiple Escape Characters
    - 2.1.4.7Single Escape Character
    - 2.1.4.8Examples of Single Escape Characters
    - 2.1.4.9Whitespace Characters
    - 2.1.4.10Examples of Whitespace Characters
- 2.2Reader Algorithm
- 2.3Interpretation of Tokens
  - 2.3.1Numbers as Tokens
    - 2.3.1.1Potential Numbers as Tokens
    - 2.3.1.2Escape Characters and Potential Numbers
    - 2.3.1.3Examples of Potential Numbers
  - 2.3.2Constructing Numbers from Tokens
    - 2.3.2.1Syntax of a Rational
      - 2.3.2.1.1Syntax of an Integer
      - 2.3.2.1.2Syntax of a Ratio
    - 2.3.2.2Syntax of a Float
    - 2.3.2.3Syntax of a Complex
  - 2.3.3The Consing Dot
  - 2.3.4Symbols as Tokens
  - 2.3.5Valid Patterns for Tokens
  - 2.3.6Package System Consistency Rules
- 2.4Standard Macro Characters
  - 2.4.1Left-Parenthesis
  - 2.4.2Right-Parenthesis
  - 2.4.3Single-Quote
    - 2.4.3.1Examples of Single-Quote
  - 2.4.4Semicolon
    - 2.4.4.1Examples of Semicolon
    - 2.4.4.2Notes about Style for Semicolon
    - 2.4.4.3Use of Single Semicolon
    - 2.4.4.4Use of Double Semicolon
    - 2.4.4.5Use of Triple Semicolon
    - 2.4.4.6Use of Quadruple Semicolon
    - 2.4.4.7Examples of Style for Semicolon
  - 2.4.5Double-Quote
  - 2.4.6Backquote
    - 2.4.6.1Notes about Backquote
  - 2.4.7Comma
  - 2.4.8Sharpsign
    - 2.4.8.1Sharpsign Backslash
    - 2.4.8.2Sharpsign Single-Quote
    - 2.4.8.3Sharpsign Left-Parenthesis
    - 2.4.8.4Sharpsign Asterisk
    - 2.4.8.5Examples of Sharpsign Asterisk
    - 2.4.8.6Sharpsign Colon
    - 2.4.8.7Sharpsign Dot
    - 2.4.8.8Sharpsign B
    - 2.4.8.9Sharpsign O
    - 2.4.8.10Sharpsign X
    - 2.4.8.11Sharpsign R
    - 2.4.8.12Sharpsign C
    - 2.4.8.13Sharpsign A
    - 2.4.8.14Sharpsign S
    - 2.4.8.15Sharpsign P
    - 2.4.8.16Sharpsign Equal-Sign
    - 2.4.8.17Sharpsign Sharpsign
    - 2.4.8.18Sharpsign Plus
    - 2.4.8.19Sharpsign Minus
    - 2.4.8.20Sharpsign Vertical-Bar
    - 2.4.8.21Examples of Sharpsign Vertical-Bar
    - 2.4.8.22Notes about Style for Sharpsign Vertical-Bar
    - 2.4.8.23Sharpsign Less-Than-Sign
    - 2.4.8.24Sharpsign Whitespace
    - 2.4.8.25Sharpsign Right-Parenthesis
  - 2.4.9Re-Reading Abbreviated Expressions
3Evaluation and Compilation
- 3.1Evaluation
  - 3.1.1Introduction to Environments
    - 3.1.1.1The Global Environment
    - 3.1.1.2Dynamic Environments
    - 3.1.1.3Lexical Environments
    - 3.1.1.4The Null Lexical Environment
    - 3.1.1.5Environment Objects
  - 3.1.2The Evaluation Model
    - 3.1.2.1Form Evaluation
    - 3.1.2.2Symbols as Forms
    - 3.1.2.3Lexical Variables
    - 3.1.2.4Dynamic Variables
    - 3.1.2.5Constant Variables
    - 3.1.2.6Symbols Naming Both Lexical and Dynamic Variables
    - 3.1.2.7Conses as Forms
    - 3.1.2.8Special Forms
    - 3.1.2.9Macro Forms
    - 3.1.2.10Function Forms
    - 3.1.2.11Lambda forms
    - 3.1.2.12Self-Evaluating Objects
    - 3.1.2.13Examples of Self-Evaluating Objects
  - 3.1.3Lambda Expressions
  - 3.1.4Closures and Lexical Binding
  - 3.1.5Shadowing
  - 3.1.6Extent
  - 3.1.7Return Values
- 3.2Compilation
  - 3.2.1Compiler Terminology
  - 3.2.2Compilation Semantics
    - 3.2.2.1Compiler Macros
    - 3.2.2.2Purpose of Compiler Macros
    - 3.2.2.3Naming of Compiler Macros
    - 3.2.2.4When Compiler Macros Are Used
    - 3.2.2.5Notes about the Implementation of Compiler Macros
    - 3.2.2.6Minimal Compilation
    - 3.2.2.7Semantic Constraints
  - 3.2.3File Compilation
    - 3.2.3.1Processing of Top Level Forms
    - 3.2.3.2Processing of Defining Macros
    - 3.2.3.3Constraints on Macros and Compiler Macros
  - 3.2.4Literal Objects in Compiled Files
    - 3.2.4.1Externalizable Objects
    - 3.2.4.2Similarity of Literal Objects
    - 3.2.4.3Similarity of Aggregate Objects
    - 3.2.4.4Definition of Similarity
    - 3.2.4.5Extensions to Similarity Rules
    - 3.2.4.6Additional Constraints on Externalizable Objects
  - 3.2.5Exceptional Situations in the Compiler
- 3.3Declarations
  - 3.3.1Minimal Declaration Processing Requirements
  - 3.3.2Declaration Specifiers
  - 3.3.3Declaration Identifiers
    - 3.3.3.1Shorthand notation for Type Declarations
  - 3.3.4Declaration Scope
    - 3.3.4.1Examples of Declaration Scope
- 3.4Lambda Lists
  - 3.4.1Ordinary Lambda Lists
    - 3.4.1.1Specifiers for the required parameters
    - 3.4.1.2Specifiers for optional parameters
    - 3.4.1.3A specifier for a rest parameter
    - 3.4.1.4Specifiers for keyword parameters
    - 3.4.1.5Suppressing Keyword Argument Checking
    - 3.4.1.6Examples of Suppressing Keyword Argument Checking
    - 3.4.1.7Specifiers for &aux variables
    - 3.4.1.8Examples of Ordinary Lambda Lists
  - 3.4.2Generic Function Lambda Lists
  - 3.4.3Specialized Lambda Lists
  - 3.4.4Macro Lambda Lists
  - 3.4.5Destructuring Lambda Lists
  - 3.4.6Boa Lambda Lists
  - 3.4.7Defsetf Lambda Lists
  - 3.4.8Deftype Lambda Lists
  - 3.4.9Define-modify-macro Lambda Lists
  - 3.4.10Define-method-combination Arguments Lambda Lists
  - 3.4.11Syntactic Interaction of Documentation Strings and Declarations
- 3.5Error Checking in Function Calls
  - 3.5.1Argument Mismatch Detection
    - 3.5.1.1Safe and Unsafe Calls
    - 3.5.1.2Error Detection Time in Safe Calls
    - 3.5.1.3Too Few Arguments
    - 3.5.1.4Too Many Arguments
    - 3.5.1.5Unrecognized Keyword Arguments
    - 3.5.1.6Invalid Keyword Arguments
    - 3.5.1.7Odd Number of Keyword Arguments
    - 3.5.1.8Destructuring Mismatch
    - 3.5.1.9Errors When Calling a Next Method
- 3.6Traversal Rules and Side Effects
- 3.7Destructive Operations
  - 3.7.1Modification of Literal Objects
  - 3.7.2Transfer of Control during a Destructive Operation
    - 3.7.2.1Examples of Transfer of Control during a Destructive Operation
- 3.8Evaluation and Compilation Dictionary
  - 3.8.1lambda (Symbol)
  - 3.8.2lambda
  - 3.8.3compile
  - 3.8.4eval
  - 3.8.5eval-when
  - 3.8.6load-time-value
  - 3.8.7quote
  - 3.8.8compiler-macro-function
  - 3.8.9define-compiler-macro
  - 3.8.10defmacro
  - 3.8.11macro-function
  - 3.8.12macroexpand
  - 3.8.13define-symbol-macro
  - 3.8.14symbol-macrolet
  - 3.8.15*macroexpand-hook*
  - 3.8.16proclaim
  - 3.8.17declaim
  - 3.8.18declare
  - 3.8.19ignore
  - 3.8.20dynamic-extent
  - 3.8.21type
  - 3.8.22inline
  - 3.8.23ftype
  - 3.8.24declaration
  - 3.8.25optimize
  - 3.8.26special
  - 3.8.27locally
  - 3.8.28the
  - 3.8.29special-operator-p
  - 3.8.30constantp
4Types and Classes
- 4.1Introduction (Types and Classes)
- 4.2Types
  - 4.2.1Data Type Definition
  - 4.2.2Type Relationships
  - 4.2.3Type Specifiers
- 4.3Classes
  - 4.3.1Introduction to Classes
    - 4.3.1.1Standard Metaclasses
  - 4.3.2Defining Classes
  - 4.3.3Creating Instances of Classes
  - 4.3.4Inheritance
    - 4.3.4.1Examples of Inheritance
    - 4.3.4.2Inheritance of Class Options
  - 4.3.5Determining the Class Precedence List
    - 4.3.5.1Topological Sorting
    - 4.3.5.2Examples of Class Precedence List Determination
  - 4.3.6Redefining Classes
    - 4.3.6.1Modifying the Structure of Instances
    - 4.3.6.2Initializing Newly Added Local Slots (Redefining Classes)
    - 4.3.6.3Customizing Class Redefinition
  - 4.3.7Integrating Types and Classes
- 4.4Types and Classes Dictionary
  - 4.4.1nil (Type)
  - 4.4.2boolean
  - 4.4.3function (System Class)
  - 4.4.4compiled-function
  - 4.4.5generic-function
  - 4.4.6standard-generic-function
  - 4.4.7class
  - 4.4.8built-in-class
  - 4.4.9structure-class
  - 4.4.10standard-class
  - 4.4.11method
  - 4.4.12standard-method
  - 4.4.13structure-object
  - 4.4.14standard-object
  - 4.4.15method-combination
  - 4.4.16t (System Class)
  - 4.4.17satisfies
  - 4.4.18member
  - 4.4.19not (Type Specifier)
  - 4.4.20and (Type Specifier)
  - 4.4.21or (Type Specifier)
  - 4.4.22values (Type Specifier)
  - 4.4.23eql (Type Specifier)
  - 4.4.24coerce
  - 4.4.25deftype
  - 4.4.26subtypep
  - 4.4.27type-of
  - 4.4.28typep
  - 4.4.29type-error
  - 4.4.30type-error-datum
  - 4.4.31simple-type-error
5Data and Control Flow
- 5.1Generalized Reference
  - 5.1.1Overview of Places and Generalized Reference
    - 5.1.1.1Evaluation of Subforms to Places
    - 5.1.1.2Examples of Evaluation of Subforms to Places
    - 5.1.1.3Setf Expansions
    - 5.1.1.4Examples of Setf Expansions
  - 5.1.2Kinds of Places
    - 5.1.2.1Variable Names as Places
    - 5.1.2.2Function Call Forms as Places
    - 5.1.2.3VALUES Forms as Places
    - 5.1.2.4THE Forms as Places
    - 5.1.2.5APPLY Forms as Places
    - 5.1.2.6Setf Expansions and Places
    - 5.1.2.7Macro Forms as Places
    - 5.1.2.8Symbol Macros as Places
    - 5.1.2.9Other Compound Forms as Places
  - 5.1.3Treatment of Other Macros Based on SETF
- 5.2Transfer of Control to an Exit Point
- 5.3Data and Control Flow Dictionary
  - 5.3.1apply
  - 5.3.2defun
  - 5.3.3fdefinition
  - 5.3.4fboundp
  - 5.3.5fmakunbound
  - 5.3.6flet
  - 5.3.7funcall
  - 5.3.8function (Special Operator)
  - 5.3.9function-lambda-expression
  - 5.3.10functionp
  - 5.3.11compiled-function-p
  - 5.3.12call-arguments-limit
  - 5.3.13lambda-list-keywords
  - 5.3.14lambda-parameters-limit
  - 5.3.15defconstant
  - 5.3.16defparameter
  - 5.3.17destructuring-bind
  - 5.3.18let
  - 5.3.19progv
  - 5.3.20setq
  - 5.3.21psetq
  - 5.3.22block
  - 5.3.23catch
  - 5.3.24go
  - 5.3.25return-from
  - 5.3.26return
  - 5.3.27tagbody
  - 5.3.28throw
  - 5.3.29unwind-protect
  - 5.3.30nil (Constant Variable)
  - 5.3.31not
  - 5.3.32t
  - 5.3.33eq
  - 5.3.34eql
  - 5.3.35equal
  - 5.3.36equalp
  - 5.3.37identity
  - 5.3.38complement
  - 5.3.39constantly
  - 5.3.40every
  - 5.3.41and
  - 5.3.42cond
  - 5.3.43if
  - 5.3.44or
  - 5.3.45when
  - 5.3.46case
  - 5.3.47typecase
  - 5.3.48multiple-value-bind
  - 5.3.49multiple-value-call
  - 5.3.50multiple-value-list
  - 5.3.51multiple-value-prog1
  - 5.3.52multiple-value-setq
  - 5.3.53values
  - 5.3.54values-list
  - 5.3.55multiple-values-limit
  - 5.3.56nth-value
  - 5.3.57prog
  - 5.3.58prog1
  - 5.3.59progn
  - 5.3.60define-modify-macro
  - 5.3.61defsetf
  - 5.3.62define-setf-expander
  - 5.3.63get-setf-expansion
  - 5.3.64setf
  - 5.3.65shiftf
  - 5.3.66rotatef
  - 5.3.67control-error
  - 5.3.68program-error
  - 5.3.69undefined-function
6Iteration
- 6.1The LOOP Facility
  - 6.1.1Overview of the Loop Facility
    - 6.1.1.1Simple vs Extended Loop
      - 6.1.1.1.1Simple Loop
      - 6.1.1.1.2Extended Loop
    - 6.1.1.2Loop Keywords
    - 6.1.1.3Parsing Loop Clauses
    - 6.1.1.4Expanding Loop Forms
    - 6.1.1.5Summary of Loop Clauses
      - 6.1.1.5.1Summary of Variable Initialization and Stepping Clauses
      - 6.1.1.5.2Summary of Value Accumulation Clauses
      - 6.1.1.5.3Summary of Termination Test Clauses
      - 6.1.1.5.4Summary of Unconditional Execution Clauses
      - 6.1.1.5.5Summary of Conditional Execution Clauses
      - 6.1.1.5.6Summary of Miscellaneous Clauses
    - 6.1.1.6Order of Execution
    - 6.1.1.7Destructuring
    - 6.1.1.8Restrictions on Side-Effects
  - 6.1.2Variable Initialization and Stepping Clauses
    - 6.1.2.1Iteration Control
    - 6.1.2.2The for-as-arithmetic subclause
    - 6.1.2.3Examples of for-as-arithmetic subclause
    - 6.1.2.4The for-as-in-list subclause
    - 6.1.2.5Examples of for-as-in-list subclause
    - 6.1.2.6The for-as-on-list subclause
    - 6.1.2.7Examples of for-as-on-list subclause
    - 6.1.2.8The for-as-equals-then subclause
    - 6.1.2.9Examples of for-as-equals-then subclause
    - 6.1.2.10The for-as-across subclause
    - 6.1.2.11Examples of for-as-across subclause
    - 6.1.2.12The for-as-hash subclause
    - 6.1.2.13The for-as-package subclause
    - 6.1.2.14Examples of for-as-package subclause
    - 6.1.2.15Local Variable Initializations
    - 6.1.2.16Examples of WITH clause
  - 6.1.3Value Accumulation Clauses
    - 6.1.3.1Examples of COLLECT clause
    - 6.1.3.2Examples of APPEND and NCONC clauses
    - 6.1.3.3Examples of COUNT clause
    - 6.1.3.4Examples of MAXIMIZE and MINIMIZE clauses
    - 6.1.3.5Examples of SUM clause
  - 6.1.4Termination Test Clauses
    - 6.1.4.1Examples of REPEAT clause
    - 6.1.4.2Examples of ALWAYS
    - 6.1.4.3Examples of WHILE and UNTIL clauses
  - 6.1.5Unconditional Execution Clauses
    - 6.1.5.1Examples of unconditional execution
  - 6.1.6Conditional Execution Clauses
    - 6.1.6.1Examples of WHEN clause
  - 6.1.7Miscellaneous Clauses
    - 6.1.7.1Control Transfer Clauses
    - 6.1.7.2Examples of NAMED clause
    - 6.1.7.3Initial and Final Execution
  - 6.1.8Examples of Miscellaneous Loop Features
    - 6.1.8.1Examples of clause grouping
  - 6.1.9Notes about Loop
- 6.2Iteration Dictionary
  - 6.2.1do
  - 6.2.2dotimes
  - 6.2.3dolist
  - 6.2.4loop
  - 6.2.5loop-finish
7Objects
- 7.1Object Creation and Initialization
- 7.2Changing the Class of an Instance
- 7.3Reinitializing an Instance
  - 7.3.1Customizing Reinitialization
- 7.4Meta-Objects
  - 7.4.1Standard Meta-objects
- 7.5Slots
  - 7.5.1Introduction to Slots
  - 7.5.2Accessing Slots
  - 7.5.3Inheritance of Slots and Slot Options
- 7.6Generic Functions and Methods
- 7.7Objects Dictionary
  - 7.7.1function-keywords
  - 7.7.2ensure-generic-function
  - 7.7.3allocate-instance
  - 7.7.4reinitialize-instance
  - 7.7.5shared-initialize
  - 7.7.6update-instance-for-different-class
  - 7.7.7update-instance-for-redefined-class
  - 7.7.8change-class
  - 7.7.9slot-boundp
  - 7.7.10slot-exists-p
  - 7.7.11slot-makunbound
  - 7.7.12slot-missing
  - 7.7.13slot-unbound
  - 7.7.14slot-value
  - 7.7.15method-qualifiers
  - 7.7.16no-applicable-method
  - 7.7.17no-next-method
  - 7.7.18remove-method
  - 7.7.19make-instance
  - 7.7.20make-instances-obsolete
  - 7.7.21make-load-form
  - 7.7.22make-load-form-saving-slots
  - 7.7.23with-accessors
  - 7.7.24with-slots
  - 7.7.25defclass
  - 7.7.26defgeneric
  - 7.7.27defmethod
  - 7.7.28find-class
  - 7.7.29next-method-p
  - 7.7.30call-method
  - 7.7.31call-next-method
  - 7.7.32compute-applicable-methods
  - 7.7.33define-method-combination
  - 7.7.34find-method
  - 7.7.35add-method
  - 7.7.36initialize-instance
  - 7.7.37class-name
  - 7.7.38(setf class-name)
  - 7.7.39class-of
  - 7.7.40unbound-slot
  - 7.7.41unbound-slot-instance
8Structures
- 8.1Structures Dictionary
  - 8.1.1defstruct
  - 8.1.2copy-structure
9Conditions
- 9.1Condition System Concepts
  - 9.1.1Condition Types
    - 9.1.1.1Serious Conditions
  - 9.1.2Creating Conditions
    - 9.1.2.1Condition Designators
  - 9.1.3Printing Conditions
    - 9.1.3.1Recommended Style in Condition Reporting
    - 9.1.3.2Capitalization and Punctuation in Condition Reports
    - 9.1.3.3Leading and Trailing Newlines in Condition Reports
    - 9.1.3.4Embedded Newlines in Condition Reports
    - 9.1.3.5Note about Tabs in Condition Reports
    - 9.1.3.6Mentioning Containing Function in Condition Reports
  - 9.1.4Signaling and Handling Conditions
    - 9.1.4.1Signaling
    - 9.1.4.2Resignaling a Condition
    - 9.1.4.3Restarts
    - 9.1.4.4Interactive Use of Restarts
    - 9.1.4.5Interfaces to Restarts
    - 9.1.4.6Restart Tests
    - 9.1.4.7Associating a Restart with a Condition
  - 9.1.5Assertions
  - 9.1.6Notes about the Condition System's Background
- 9.2Conditions Dictionary
  - 9.2.1condition
  - 9.2.2warning
  - 9.2.3style-warning
  - 9.2.4serious-condition
  - 9.2.5error (Condition Type)
  - 9.2.6cell-error
  - 9.2.7cell-error-name
  - 9.2.8parse-error
  - 9.2.9storage-condition
  - 9.2.10assert
  - 9.2.11error
  - 9.2.12cerror
  - 9.2.13check-type
  - 9.2.14simple-error
  - 9.2.15invalid-method-error
  - 9.2.16method-combination-error
  - 9.2.17signal
  - 9.2.18simple-condition
  - 9.2.19simple-condition-format-control
  - 9.2.20warn
  - 9.2.21simple-warning
  - 9.2.22invoke-debugger
  - 9.2.23break
  - 9.2.24*debugger-hook*
  - 9.2.25*break-on-signals*
  - 9.2.26handler-bind
  - 9.2.27handler-case
  - 9.2.28ignore-errors
  - 9.2.29define-condition
  - 9.2.30make-condition
  - 9.2.31restart
  - 9.2.32compute-restarts
  - 9.2.33find-restart
  - 9.2.34invoke-restart
  - 9.2.35invoke-restart-interactively
  - 9.2.36restart-bind
  - 9.2.37restart-case
  - 9.2.38restart-name
  - 9.2.39with-condition-restarts
  - 9.2.40with-simple-restart
  - 9.2.41abort
  - 9.2.42continue
  - 9.2.43muffle-warning
  - 9.2.44store-value
  - 9.2.45use-value
  - 9.2.46use-value
10Symbols
- 10.1Symbol Concepts
- 10.2Symbols Dictionary
  - 10.2.1symbol
  - 10.2.2keyword
  - 10.2.3symbolp
  - 10.2.4keywordp
  - 10.2.5make-symbol
  - 10.2.6copy-symbol
  - 10.2.7gensym
  - 10.2.8*gensym-counter*
  - 10.2.9gentemp
  - 10.2.10symbol-function
  - 10.2.11symbol-name
  - 10.2.12symbol-package
  - 10.2.13symbol-plist
  - 10.2.14symbol-value
  - 10.2.15get
  - 10.2.16remprop
  - 10.2.17boundp
  - 10.2.18makunbound
  - 10.2.19set
  - 10.2.20unbound-variable
11Packages
- 11.1Package Concepts
  - 11.1.1Introduction to Packages
    - 11.1.1.1Package Names and Nicknames
    - 11.1.1.2Symbols in a Package
    - 11.1.1.3Internal and External Symbols
    - 11.1.1.4Package Inheritance
    - 11.1.1.5Accessibility of Symbols in a Package
    - 11.1.1.6Locating a Symbol in a Package
    - 11.1.1.7Prevention of Name Conflicts in Packages
  - 11.1.2Standardized Packages
    - 11.1.2.1The COMMON-LISP Package
    - 11.1.2.2Constraints on the COMMON-LISP Package for Conforming Implementations
    - 11.1.2.3Constraints on the COMMON-LISP Package for Conforming Programs
    - 11.1.2.4Some Exceptions to Constraints on the COMMON-LISP Package for Conforming Programs
    - 11.1.2.5The COMMON-LISP-USER Package
    - 11.1.2.6The KEYWORD Package
    - 11.1.2.7Interning a Symbol in the KEYWORD Package
    - 11.1.2.8Notes about The KEYWORD Package
    - 11.1.2.9Implementation-Defined Packages
- 11.2Packages Dictionary
  - 11.2.1package
  - 11.2.2export
  - 11.2.3find-symbol
  - 11.2.4find-package
  - 11.2.5find-all-symbols
  - 11.2.6import
  - 11.2.7list-all-packages
  - 11.2.8rename-package
  - 11.2.9shadow
  - 11.2.10shadowing-import
  - 11.2.11delete-package
  - 11.2.12make-package
  - 11.2.13with-package-iterator
  - 11.2.14unexport
  - 11.2.15unintern
  - 11.2.16in-package
  - 11.2.17unuse-package
  - 11.2.18use-package
  - 11.2.19defpackage
  - 11.2.20do-symbols
  - 11.2.21intern
  - 11.2.22package-name
  - 11.2.23package-nicknames
  - 11.2.24package-shadowing-symbols
  - 11.2.25package-use-list
  - 11.2.26package-used-by-list
  - 11.2.27packagep
  - 11.2.28*package*
  - 11.2.29package-error
  - 11.2.30package-error-package
12Numbers (Numbers)
- 12.1Number Concepts
  - 12.1.1Numeric Operations
    - 12.1.1.1Associativity and Commutativity in Numeric Operations
    - 12.1.1.2Examples of Associativity and Commutativity in Numeric Operations
    - 12.1.1.3Contagion in Numeric Operations
    - 12.1.1.4Viewing Integers as Bits and Bytes
    - 12.1.1.5Logical Operations on Integers
    - 12.1.1.6Byte Operations on Integers
  - 12.1.2Implementation-Dependent Numeric Constants
  - 12.1.3Rational Computations
    - 12.1.3.1Rule of Unbounded Rational Precision
    - 12.1.3.2Rule of Canonical Representation for Rationals
    - 12.1.3.3Rule of Float Substitutability
  - 12.1.4Floating-point Computations
    - 12.1.4.1Rule of Float and Rational Contagion
    - 12.1.4.2Examples of Rule of Float and Rational Contagion
    - 12.1.4.3Rule of Float Approximation
    - 12.1.4.4Rule of Float Underflow and Overflow
    - 12.1.4.5Rule of Float Precision Contagion
  - 12.1.5Complex Computations
    - 12.1.5.1Rule of Complex Substitutability
    - 12.1.5.2Rule of Complex Contagion
    - 12.1.5.3Rule of Canonical Representation for Complex Rationals
    - 12.1.5.4Examples of Rule of Canonical Representation for Complex Rationals
    - 12.1.5.5Principal Values and Branch Cuts
  - 12.1.6Interval Designators
  - 12.1.7Random-State Operations
- 12.2Numbers Dictionary
  - 12.2.1number
  - 12.2.2complex (System Class)
  - 12.2.3real
  - 12.2.4float (System Class)
  - 12.2.5short-float
  - 12.2.6rational
  - 12.2.7ratio
  - 12.2.8integer
  - 12.2.9signed-byte
  - 12.2.10unsigned-byte
  - 12.2.11mod (Type Specifier)
  - 12.2.12bit
  - 12.2.13fixnum
  - 12.2.14bignum
  - 12.2.15=
  - 12.2.16max
  - 12.2.17minusp
  - 12.2.18zerop
  - 12.2.19floor
  - 12.2.20sin
  - 12.2.21asin
  - 12.2.22pi
  - 12.2.23sinh
  - 12.2.24*
  - 12.2.25+
  - 12.2.26-
  - 12.2.27/
  - 12.2.281+
  - 12.2.29abs
  - 12.2.30evenp
  - 12.2.31exp
  - 12.2.32gcd
  - 12.2.33incf
  - 12.2.34lcm
  - 12.2.35log
  - 12.2.36rem
  - 12.2.37signum
  - 12.2.38sqrt
  - 12.2.39random-state
  - 12.2.40make-random-state
  - 12.2.41random
  - 12.2.42random-state-p
  - 12.2.43*random-state*
  - 12.2.44numberp
  - 12.2.45cis
  - 12.2.46complex
  - 12.2.47complexp
  - 12.2.48conjugate
  - 12.2.49phase
  - 12.2.50realpart
  - 12.2.51upgraded-complex-part-type
  - 12.2.52realp
  - 12.2.53numerator
  - 12.2.54rationalize
  - 12.2.55rationalp
  - 12.2.56ash
  - 12.2.57integer-length
  - 12.2.58integerp
  - 12.2.59parse-integer
  - 12.2.60boole
  - 12.2.61boole-1
  - 12.2.62logand
  - 12.2.63logbitp
  - 12.2.64logcount
  - 12.2.65logtest
  - 12.2.66byte
  - 12.2.67deposit-field
  - 12.2.68dpb
  - 12.2.69ldb
  - 12.2.70ldb-test
  - 12.2.71mask-field
  - 12.2.72most-positive-fixnum
  - 12.2.73decode-float
  - 12.2.74float
  - 12.2.75floatp
  - 12.2.76most-positive-short-float
  - 12.2.77short-float-epsilon
  - 12.2.78arithmetic-error
  - 12.2.79arithmetic-error-operands
  - 12.2.80division-by-zero
  - 12.2.81floating-point-invalid-operation
  - 12.2.82floating-point-inexact
  - 12.2.83floating-point-overflow
  - 12.2.84floating-point-underflow
13Characters
- 13.1Character Concepts
  - 13.1.1Introduction to Characters
  - 13.1.2Introduction to Scripts and Repertoires
    - 13.1.2.1Character Scripts
    - 13.1.2.2Character Repertoires
  - 13.1.3Character Attributes
  - 13.1.4Character Categories
    - 13.1.4.1Graphic Characters
    - 13.1.4.2Alphabetic Characters
    - 13.1.4.3Characters With Case
    - 13.1.4.4Uppercase Characters
    - 13.1.4.5Lowercase Characters
    - 13.1.4.6Corresponding Characters in the Other Case
    - 13.1.4.7Case of Implementation-Defined Characters
    - 13.1.4.8Numeric Characters
    - 13.1.4.9Alphanumeric Characters
    - 13.1.4.10Digits in a Radix
  - 13.1.5Identity of Characters
  - 13.1.6Ordering of Characters
  - 13.1.7Character Names
  - 13.1.8Treatment of Newline during Input and Output
  - 13.1.9Character Encodings
  - 13.1.10Documentation of Implementation-Defined Scripts
- 13.2Characters Dictionary
  - 13.2.1character (System Class)
  - 13.2.2base-char
  - 13.2.3standard-char
  - 13.2.4extended-char
  - 13.2.5char=
  - 13.2.6character
  - 13.2.7characterp
  - 13.2.8alpha-char-p
  - 13.2.9alphanumericp
  - 13.2.10digit-char
  - 13.2.11digit-char-p
  - 13.2.12graphic-char-p
  - 13.2.13standard-char-p
  - 13.2.14char-upcase
  - 13.2.15upper-case-p
  - 13.2.16char-code
  - 13.2.17char-int
  - 13.2.18code-char
  - 13.2.19char-code-limit
  - 13.2.20char-name
  - 13.2.21name-char
14Conses
- 14.1Cons Concepts
  - 14.1.1Conses as Trees
    - 14.1.1.1General Restrictions on Parameters that must be Trees
  - 14.1.2Conses as Lists
    - 14.1.2.1Lists as Association Lists
    - 14.1.2.2Lists as Sets
    - 14.1.2.3General Restrictions on Parameters that must be Lists
- 14.2Conses Dictionary
  - 14.2.1list
  - 14.2.2null (System Class)
  - 14.2.3cons (System Class)
  - 14.2.4atom (Type)
  - 14.2.5cons
  - 14.2.6consp
  - 14.2.7atom
  - 14.2.8rplaca
  - 14.2.9car
  - 14.2.10copy-tree
  - 14.2.11sublis
  - 14.2.12subst
  - 14.2.13tree-equal
  - 14.2.14copy-list
  - 14.2.15list*
  - 14.2.16list-length
  - 14.2.17listp
  - 14.2.18make-list
  - 14.2.19push
  - 14.2.20pop
  - 14.2.21first
  - 14.2.22nth
  - 14.2.23endp
  - 14.2.24null
  - 14.2.25nconc
  - 14.2.26append
  - 14.2.27revappend
  - 14.2.28butlast
  - 14.2.29last
  - 14.2.30ldiff
  - 14.2.31nthcdr
  - 14.2.32rest
  - 14.2.33member-if-not
  - 14.2.34mapc
  - 14.2.35acons
  - 14.2.36assoc
  - 14.2.37copy-alist
  - 14.2.38pairlis
  - 14.2.39rassoc
  - 14.2.40get-properties
  - 14.2.41getf
  - 14.2.42remf
  - 14.2.43intersection
  - 14.2.44adjoin
  - 14.2.45pushnew
  - 14.2.46set-difference
  - 14.2.47set-exclusive-or
  - 14.2.48subsetp
  - 14.2.49union
15Arrays
- 15.1Array Concepts
  - 15.1.1Array Elements
    - 15.1.1.1Array Indices
    - 15.1.1.2Array Dimensions
      - 15.1.1.2.1Implementation Limits on Individual Array Dimensions
    - 15.1.1.4Array Rank
      - 15.1.1.3.1Vectors
        15.1.1.3.1.1Fill Pointers
      - 15.1.1.3.2Multidimensional Arrays
        15.1.1.3.2.1Storage Layout for Multidimensional Arrays
        15.1.1.3.2.2Implementation Limits on Array Rank
  - 15.1.2Specialized Arrays
    - 15.1.2.1Array Upgrading
    - 15.1.2.2Required Kinds of Specialized Arrays
- 15.2Arrays Dictionary
  - 15.2.1array
  - 15.2.2simple-array
  - 15.2.3vector (System Class)
  - 15.2.4simple-vector
  - 15.2.5bit-vector
  - 15.2.6simple-bit-vector
  - 15.2.7make-array
  - 15.2.8adjust-array
  - 15.2.9adjustable-array-p
  - 15.2.10aref
  - 15.2.11array-dimension
  - 15.2.12array-dimensions
  - 15.2.13array-element-type
  - 15.2.14array-has-fill-pointer-p
  - 15.2.15array-displacement
  - 15.2.16array-in-bounds-p
  - 15.2.17array-rank
  - 15.2.18array-row-major-index
  - 15.2.19array-total-size
  - 15.2.20arrayp
  - 15.2.21fill-pointer
  - 15.2.22row-major-aref
  - 15.2.23upgraded-array-element-type
  - 15.2.24array-dimension-limit
  - 15.2.25array-rank-limit
  - 15.2.26array-total-size-limit
  - 15.2.27simple-vector-p
  - 15.2.28svref
  - 15.2.29vector
  - 15.2.30vector-pop
  - 15.2.31vector-push
  - 15.2.32vectorp
  - 15.2.33sbit
  - 15.2.34bit-and
  - 15.2.35bit-vector-p
  - 15.2.36simple-bit-vector-p
16Strings
- 16.1String Concepts
  - 16.1.1Implications of Strings Being Arrays
  - 16.1.2Subtypes of STRING
- 16.2Strings Dictionary
  - 16.2.1string (System Class)
  - 16.2.2base-string
  - 16.2.3simple-string
  - 16.2.4simple-base-string
  - 16.2.5simple-string-p
  - 16.2.6char
  - 16.2.7string
  - 16.2.8string-upcase
  - 16.2.9string-trim
  - 16.2.10string=
  - 16.2.11stringp
  - 16.2.12make-string
17Sequences
- 17.1Sequence Concepts
  - 17.1.1General Restrictions on Parameters that must be Sequences
- 17.2Rules about Test Functions
  - 17.2.1Satisfying a Two-Argument Test
    - 17.2.1.1Examples of Satisfying a Two-Argument Test
  - 17.2.2Satisfying a One-Argument Test
    - 17.2.2.1Examples of Satisfying a One-Argument Test
- 17.3Sequences Dictionary
  - 17.3.1sequence
  - 17.3.2copy-seq
  - 17.3.3elt
  - 17.3.4fill
  - 17.3.5make-sequence
  - 17.3.6subseq
  - 17.3.7map
  - 17.3.8map-into
  - 17.3.9reduce
  - 17.3.10count
  - 17.3.11length
  - 17.3.12reverse
  - 17.3.13sort
  - 17.3.14find
  - 17.3.15position
  - 17.3.16search
  - 17.3.17mismatch
  - 17.3.18replace
  - 17.3.19substitute
  - 17.3.20concatenate
  - 17.3.21merge
  - 17.3.22remove
  - 17.3.23remove-duplicates
18Hash Tables
- 18.1Hash Table Concepts
  - 18.1.1Hash-Table Operations
  - 18.1.2Modifying Hash Table Keys
- 18.2Hash Tables Dictionary
  - 18.2.1hash-table
  - 18.2.2make-hash-table
  - 18.2.3hash-table-p
  - 18.2.4hash-table-count
  - 18.2.5hash-table-rehash-size
  - 18.2.6hash-table-rehash-threshold
  - 18.2.7hash-table-size
  - 18.2.8hash-table-test
  - 18.2.9gethash
  - 18.2.10remhash
  - 18.2.11maphash
  - 18.2.12with-hash-table-iterator
  - 18.2.13clrhash
  - 18.2.14sxhash
19Filenames
- 19.1Overview of Filenames
  - 19.1.1Namestrings as Filenames
  - 19.1.2Pathnames as Filenames
  - 19.1.3Parsing Namestrings Into Pathnames
- 19.2Pathnames
  - 19.2.1Pathname Components
    - 19.2.1.1The Pathname Host Component
    - 19.2.1.2The Pathname Device Component
    - 19.2.1.3The Pathname Directory Component
    - 19.2.1.4The Pathname Name Component
    - 19.2.1.5The Pathname Type Component
    - 19.2.1.6The Pathname Version Component
  - 19.2.2Interpreting Pathname Component Values
    - 19.2.2.1Strings in Component Values
    - 19.2.2.2Special Characters in Pathname Components
    - 19.2.2.3Case in Pathname Components
    - 19.2.2.4Local Case in Pathname Components
    - 19.2.2.5Common Case in Pathname Components
    - 19.2.2.6Special Pathname Component Values
    - 19.2.2.7NIL as a Component Value
    - 19.2.2.8->WILD as a Component Value
    - 19.2.2.9->UNSPECIFIC as a Component Value
    - 19.2.2.10Relation between component values NIL and ->UNSPECIFIC
    - 19.2.2.11Restrictions on Wildcard Pathnames
    - 19.2.2.12Restrictions on Examining Pathname Components
    - 19.2.2.13Restrictions on Examining a Pathname Host Component
    - 19.2.2.14Restrictions on Examining a Pathname Device Component
    - 19.2.2.15Restrictions on Examining a Pathname Directory Component
    - 19.2.2.16Directory Components in Non-Hierarchical File Systems
    - 19.2.2.17Restrictions on Examining a Pathname Name Component
    - 19.2.2.18Restrictions on Examining a Pathname Type Component
    - 19.2.2.19Restrictions on Examining a Pathname Version Component
    - 19.2.2.20Notes about the Pathname Version Component
    - 19.2.2.21Restrictions on Constructing Pathnames
  - 19.2.3Merging Pathnames
    - 19.2.3.1Examples of Merging Pathnames
- 19.3Logical Pathnames
  - 19.3.1Syntax of Logical Pathname Namestrings
    - 19.3.1.1Additional Information about Parsing Logical Pathname Namestrings
    - 19.3.1.2The Host part of a Logical Pathname Namestring
    - 19.3.1.3The Device part of a Logical Pathname Namestring
    - 19.3.1.4The Directory part of a Logical Pathname Namestring
    - 19.3.1.5The Type part of a Logical Pathname Namestring
    - 19.3.1.6The Version part of a Logical Pathname Namestring
    - 19.3.1.7Wildcard Words in a Logical Pathname Namestring
    - 19.3.1.8Lowercase Letters in a Logical Pathname Namestring
    - 19.3.1.9Other Syntax in a Logical Pathname Namestring
  - 19.3.2Logical Pathname Components
    - 19.3.2.1Unspecific Components of a Logical Pathname
    - 19.3.2.2Null Strings as Components of a Logical Pathname
- 19.4Filenames Dictionary
  - 19.4.1pathname (System Class)
  - 19.4.2logical-pathname (System Class)
  - 19.4.3pathname
  - 19.4.4make-pathname
  - 19.4.5pathnamep
  - 19.4.6pathname-host
  - 19.4.7load-logical-pathname-translations
  - 19.4.8logical-pathname-translations
  - 19.4.9logical-pathname
  - 19.4.10*default-pathname-defaults*
  - 19.4.11namestring
  - 19.4.12parse-namestring
  - 19.4.13wild-pathname-p
  - 19.4.14pathname-match-p
  - 19.4.15translate-logical-pathname
  - 19.4.16translate-pathname
  - 19.4.17merge-pathnames
20Files
- 20.1File System Concepts
  - 20.1.1Coercion of Streams to Pathnames
  - 20.1.2File Operations on Open and Closed Streams
  - 20.1.3Truenames
    - 20.1.3.1Examples of Truenames
- 20.2Files Dictionary
  - 20.2.1directory
  - 20.2.2probe-file
  - 20.2.3ensure-directories-exist
  - 20.2.4truename
  - 20.2.5file-author
  - 20.2.6file-write-date
  - 20.2.7rename-file
  - 20.2.8delete-file
  - 20.2.9file-error
  - 20.2.10file-error-pathname
21Streams
- 21.1Stream Concepts
  - 21.1.1Introduction to Streams
    - 21.1.1.1Abstract Classifications of Streams (Introduction to Streams)
    - 21.1.1.2Input
    - 21.1.1.3Open and Closed Streams
    - 21.1.1.4Interactive Streams
    - 21.1.1.5Abstract Classifications of Streams
    - 21.1.1.6File Streams
    - 21.1.1.7Other Subclasses of Stream
  - 21.1.2Stream Variables
  - 21.1.3Stream Arguments to Standardized Functions
  - 21.1.4Restrictions on Composite Streams
- 21.2Streams Dictionary
  - 21.2.1stream
  - 21.2.2broadcast-stream
  - 21.2.3concatenated-stream
  - 21.2.4echo-stream
  - 21.2.5file-stream
  - 21.2.6string-stream
  - 21.2.7synonym-stream
  - 21.2.8two-way-stream
  - 21.2.9input-stream-p
  - 21.2.10interactive-stream-p
  - 21.2.11open-stream-p
  - 21.2.12stream-element-type
  - 21.2.13streamp
  - 21.2.14read-byte
  - 21.2.15write-byte
  - 21.2.16peek-char
  - 21.2.17read-char
  - 21.2.18read-char-no-hang
  - 21.2.19terpri
  - 21.2.20unread-char
  - 21.2.21write-char
  - 21.2.22read-line
  - 21.2.23write-string
  - 21.2.24read-sequence
  - 21.2.25write-sequence
  - 21.2.26file-length
  - 21.2.27file-position
  - 21.2.28file-string-length
  - 21.2.29open
  - 21.2.30stream-external-format
  - 21.2.31with-open-file
  - 21.2.32close
  - 21.2.33with-open-stream
  - 21.2.34listen
  - 21.2.35clear-input
  - 21.2.36finish-output
  - 21.2.37y-or-n-p
  - 21.2.38make-synonym-stream
  - 21.2.39synonym-stream-symbol
  - 21.2.40broadcast-stream-streams
  - 21.2.41make-broadcast-stream
  - 21.2.42make-two-way-stream
  - 21.2.43two-way-stream-input-stream
  - 21.2.44echo-stream-input-stream
  - 21.2.45make-echo-stream
  - 21.2.46concatenated-stream-streams
  - 21.2.47make-concatenated-stream
  - 21.2.48get-output-stream-string
  - 21.2.49make-string-input-stream
  - 21.2.50make-string-output-stream
  - 21.2.51with-input-from-string
  - 21.2.52with-output-to-string
  - 21.2.53*debug-io*
  - 21.2.54*terminal-io*
  - 21.2.55stream-error
  - 21.2.56stream-error-stream
  - 21.2.57end-of-file
22Printer
- 22.1The Lisp Printer
  - 22.1.1Overview of The Lisp Printer
    - 22.1.1.1Multiple Possible Textual Representations
    - 22.1.1.2Printer Escaping
  - 22.1.2Printer Dispatching
  - 22.1.3Default Print-Object Methods
    - 22.1.3.1Printing Numbers
    - 22.1.3.2Printing Integers
    - 22.1.3.3Printing Ratios
    - 22.1.3.4Printing Floats
    - 22.1.3.5Printing Complexes
    - 22.1.3.6Note about Printing Numbers
    - 22.1.3.7Printing Characters
    - 22.1.3.8Printing Symbols
    - 22.1.3.9Package Prefixes for Symbols
    - 22.1.3.10Effect of Readtable Case on the Lisp Printer
    - 22.1.3.11Examples of Effect of Readtable Case on the Lisp Printer
    - 22.1.3.12Printing Strings
    - 22.1.3.13Printing Lists and Conses
    - 22.1.3.14Printing Bit Vectors
    - 22.1.3.15Printing Other Vectors
    - 22.1.3.16Printing Other Arrays
    - 22.1.3.17Examples of Printing Arrays
    - 22.1.3.18Printing Random States
    - 22.1.3.19Printing Pathnames
    - 22.1.3.20Printing Structures
    - 22.1.3.21Printing Other Objects
  - 22.1.4Examples of Printer Behavior
- 22.2The Lisp Pretty Printer
  - 22.2.1Pretty Printer Concepts
    - 22.2.1.1Dynamic Control of the Arrangement of Output
    - 22.2.1.2Format Directive Interface
    - 22.2.1.3Compiling Format Strings
    - 22.2.1.4Pretty Print Dispatch Tables
    - 22.2.1.5Pretty Printer Margins
  - 22.2.2Examples of using the Pretty Printer
  - 22.2.3Notes about the Pretty Printer's Background
- 22.3Formatted Output
  - 22.3.1FORMAT Basic Output
    - 22.3.1.1Tilde C-> Character
    - 22.3.1.2Tilde Percent-> Newline
    - 22.3.1.3Tilde Ampersand-> Fresh-Line
    - 22.3.1.4Tilde Vertical-Bar-> Page
    - 22.3.1.5Tilde Tilde-> Tilde
  - 22.3.2FORMAT Radix Control
    - 22.3.2.1Tilde R-> Radix
    - 22.3.2.2Tilde D-> Decimal
    - 22.3.2.3Tilde B-> Binary
    - 22.3.2.4Tilde O-> Octal
    - 22.3.2.5Tilde X-> Hexadecimal
  - 22.3.3FORMAT Floating-Point Printers
    - 22.3.3.1Tilde F-> Fixed-Format Floating-Point
    - 22.3.3.2Tilde E-> Exponential Floating-Point
    - 22.3.3.3Tilde G-> General Floating-Point
    - 22.3.3.4Tilde Dollarsign-> Monetary Floating-Point
  - 22.3.4FORMAT Printer Operations
    - 22.3.4.1Tilde A-> Aesthetic
    - 22.3.4.2Tilde S-> Standard
    - 22.3.4.3Tilde W-> Write
  - 22.3.5FORMAT Pretty Printer Operations
    - 22.3.5.1Tilde Underscore-> Conditional Newline
    - 22.3.5.2Tilde Less-Than-Sign-> Logical Block
    - 22.3.5.3Tilde I-> Indent
    - 22.3.5.4Tilde Slash-> Call Function
  - 22.3.6FORMAT Layout Control
    - 22.3.6.1Tilde T-> Tabulate
    - 22.3.6.2Tilde Less-Than-Sign-> Justification
    - 22.3.6.3Tilde Greater-Than-Sign-> End of Justification
  - 22.3.7FORMAT Control-Flow Operations
    - 22.3.7.1Tilde Asterisk-> Go-To
    - 22.3.7.2Tilde Left-Bracket-> Conditional Expression
    - 22.3.7.3Tilde Right-Bracket-> End of Conditional Expression
    - 22.3.7.4Tilde Left-Brace-> Iteration
    - 22.3.7.5Tilde Right-Brace-> End of Iteration
    - 22.3.7.6Tilde Question-Mark-> Recursive Processing
  - 22.3.8FORMAT Miscellaneous Operations
    - 22.3.8.1Tilde Left-Paren-> Case Conversion
    - 22.3.8.2Tilde Right-Paren-> End of Case Conversion
    - 22.3.8.3Tilde P-> Plural
  - 22.3.9FORMAT Miscellaneous Pseudo-Operations
    - 22.3.9.1Tilde Semicolon-> Clause Separator
    - 22.3.9.2Tilde Circumflex-> Escape Upward
    - 22.3.9.3Tilde Newline-> Ignored Newline
  - 22.3.10Additional Information about FORMAT Operations
    - 22.3.10.1Nesting of FORMAT Operations
    - 22.3.10.2Missing and Additional FORMAT Arguments
    - 22.3.10.3Additional FORMAT Parameters
    - 22.3.10.4Undefined FORMAT Modifier Combinations
  - 22.3.11Examples of FORMAT
  - 22.3.12Notes about FORMAT
- 22.4Printer Dictionary
  - 22.4.1copy-pprint-dispatch
  - 22.4.2formatter
  - 22.4.3pprint-dispatch
  - 22.4.4pprint-exit-if-list-exhausted
  - 22.4.5pprint-fill
  - 22.4.6pprint-indent
  - 22.4.7pprint-logical-block
  - 22.4.8pprint-newline
  - 22.4.9pprint-pop
  - 22.4.10pprint-tab
  - 22.4.11print-object
  - 22.4.12print-unreadable-object
  - 22.4.13set-pprint-dispatch
  - 22.4.14write
  - 22.4.15write-to-string
  - 22.4.16*print-array*
  - 22.4.17*print-base*
  - 22.4.18*print-case*
  - 22.4.19*print-circle*
  - 22.4.20*print-escape*
  - 22.4.21*print-gensym*
  - 22.4.22*print-level*
  - 22.4.23*print-lines*
  - 22.4.24*print-miser-width*
  - 22.4.25*print-pprint-dispatch*
  - 22.4.26*print-pretty*
  - 22.4.27*print-readably*
  - 22.4.28*print-right-margin*
  - 22.4.29print-not-readable
  - 22.4.30print-not-readable-object
  - 22.4.31format
23Reader
- 23.1Reader Concepts
  - 23.1.1Dynamic Control of the Lisp Reader
  - 23.1.2Effect of Readtable Case on the Lisp Reader
    - 23.1.2.1Examples of Effect of Readtable Case on the Lisp Reader
  - 23.1.3Argument Conventions of Some Reader Functions
    - 23.1.3.1The EOF-ERROR-P argument
    - 23.1.3.2The RECURSIVE-P argument
- 23.2Reader Dictionary
  - 23.2.1readtable
  - 23.2.2copy-readtable
  - 23.2.3make-dispatch-macro-character
  - 23.2.4read
  - 23.2.5read-delimited-list
  - 23.2.6read-from-string
  - 23.2.7readtable-case
  - 23.2.8readtablep
  - 23.2.9set-dispatch-macro-character
  - 23.2.10set-macro-character
  - 23.2.11set-syntax-from-char
  - 23.2.12with-standard-io-syntax
  - 23.2.13*read-base*
  - 23.2.14*read-default-float-format*
  - 23.2.15*read-eval*
  - 23.2.16*read-suppress*
  - 23.2.17*readtable*
  - 23.2.18reader-error
24System Construction
- 24.1System Construction Concepts
  - 24.1.1Loading
  - 24.1.2Features
    - 24.1.2.1Feature Expressions
    - 24.1.2.2Examples of Feature Expressions
- 24.2System Construction Dictionary
  - 24.2.1compile-file
  - 24.2.2compile-file-pathname
  - 24.2.3load
  - 24.2.4with-compilation-unit
  - 24.2.5*features*
  - 24.2.6*compile-file-pathname*
  - 24.2.7*load-pathname*
  - 24.2.8*compile-print*
  - 24.2.9*load-print*
  - 24.2.10*modules*
  - 24.2.11provide
25Environment
- 25.1The External Environment
  - 25.1.1Top level loop
  - 25.1.2Debugging Utilities
  - 25.1.3Environment Inquiry
  - 25.1.4Time
    - 25.1.4.1Decoded Time
    - 25.1.4.2Universal Time
    - 25.1.4.3Internal Time
    - 25.1.4.4Seconds
- 25.2Environment Dictionary
  - 25.2.1decode-universal-time
  - 25.2.2encode-universal-time
  - 25.2.3get-universal-time
  - 25.2.4sleep
  - 25.2.5apropos
  - 25.2.6describe
  - 25.2.7describe-object
  - 25.2.8trace
  - 25.2.9step
  - 25.2.10time (Macro)
  - 25.2.11internal-time-units-per-second
  - 25.2.12get-internal-real-time
  - 25.2.13get-internal-run-time
  - 25.2.14disassemble
  - 25.2.15documentation
  - 25.2.16room
  - 25.2.17ed
  - 25.2.18inspect
  - 25.2.19dribble
  - 25.2.20-
  - 25.2.21+++
  - 25.2.22***
  - 25.2.23///
  - 25.2.24lisp-implementation-type
  - 25.2.25short-site-name
  - 25.2.26machine-instance
  - 25.2.27machine-type
  - 25.2.28machine-version
  - 25.2.29software-type
  - 25.2.30user-homedir-pathname
26Glossary (Glossary)
- 26.1Glossary
27Appendix
- 27.1Removed Language Features
  - 27.1.1Requirements for removed and deprecated features
  - 27.1.2Removed Types
  - 27.1.3Removed Operators
  - 27.1.4Removed Argument Conventions
  - 27.1.5Removed Variables
  - 27.1.6Removed Reader Syntax
  - 27.1.7Packages No Longer Required

Function

null

null object ⇒ boolean

Arguments and Values

object	an object.
boolean	a boolean.

Description

Returns t if object is the empty list; otherwise, returns nil.

Examples

 (null '()) ⇒  T
 (null nil) ⇒  T
 (null t) ⇒  NIL
 (null 1) ⇒  NIL

Notes

null is intended to be used to test for the empty list whereas not is intended to be used to invert a boolean (or generalized boolean). Operationally, null and not compute the same result; which to use is a matter of style.

 (null object) ≡ (typep object 'null) ≡ (eq object '())

Backlinks

Conses Dictionary, Integrating Types and Classes, list, nil, not, null, Symbols in the COMMON-LISP Package, Type Specifiers