lispdoc - results for null 

(null object)
Function: Return true if OBJECT is a NULL, and NIL otherwise.
Example:
(defun queue-empty-p (queue) (null (car queue)))
Mentioned in:
CLtL2 - 2.15. Overlap, Inclusion, and Disjointness of Types
CLtL2 - 2.4. Lists and Conses
CLtL2 - 28.1.4. Integrating Types and Classes
CLtL2 - 4.4. Type Specifiers That Combine
CLtL2 - 4.5. Type Specifiers That Specialize
CLtL2 - 6.2.2. Specific Data Type Predicates
CLtL2 - 6.4. Logical Operators
CLtL2 - 7.8.2. General Iteration
HyperSpec - 19.3.2.2 Null Strings as Components of a Logical Pathname
HyperSpec - 3.1.1.3.1 The Null Lexical Environment
HyperSpec - Function NULL
HyperSpec - System Class NULL
On Lisp - Adding Prolog Features
On Lisp - Anaphoric Variants
On Lisp - Birth of a Utility
On Lisp - Chapter _28
On Lisp - Code-Walkers and CPS Conversion
On Lisp - Continuation-Passing Macros
On Lisp - Functional Arguments
On Lisp - Functional Design
On Lisp - Iteration with Multiple Values
On Lisp - Local Functions
On Lisp - Non-functional Expanders
On Lisp - Objects in Plain Lisp
On Lisp - Operations on Lists
On Lisp - Recursion on Cdrs
On Lisp - Recursion on Cdrs (Macros Returning Functions)
PCL - list manipulation functions
Successful Lisp - global vars and consts
non-null
 
 Mentioned in:
HyperSpec - 1.4.4.20.3 Requiring Non-Null Rest Parameters in the ``Syntax'' Section
(cffi-sys:null-pointer)
Function: Construct and return a null pointer.
  
(cffi-sys:null-pointer-p ptr)
Function: Return true if PTR is a null pointer.
  
nil
Undocumented
Example:
(defun default-driver-code () nil)
Mentioned in:
CLtL2 - 1.2.2. Nil, False, and the Empty List
CLtL2 - 13.4. Character Conversions
CLtL2 - 25.3. Debugging Tools
CLtL2 - 29.2. Changes in Terminology
CLtL2 - 3. Scope and Extent
CLtL2 - 4.8. Type Conversion Function
HyperSpec - 1.4.1.4.4 NIL
HyperSpec - 19.2.2.2.1 NIL as a Component Value
HyperSpec - 19.2.2.2.3.1 Relation between component values NIL and :UNSPECIFIC
HyperSpec - Constant Variable NIL
HyperSpec - Type NIL
On Lisp - A Query Compiler (AQC)
On Lisp - A Sample ATN
On Lisp - Adding Prolog Features
On Lisp - An ATN Compiler
On Lisp - An Interpreter
On Lisp - Anaphoric Macros (Macro-Defining Macros)
On Lisp - Anaphoric Variants
On Lisp - Applications for Macros
On Lisp - Auxiliary Methods and Combination
On Lisp - Birth of a Utility
On Lisp - CLOS and Lisp
On Lisp - Chapter _28
On Lisp - Classes and Instances
On Lisp - Code-Walkers and CPS Conversion
On Lisp - Common Lisp Implementation
On Lisp - Compiling Networks
On Lisp - Conditional Evaluation
On Lisp - Continuation-Passing Macros
On Lisp - Creating Context
On Lisp - Defining Simple Macros
On Lisp - Destructuring in Parameter Lists
On Lisp - Free Symbol Capture
On Lisp - Functional Arguments
On Lisp - Functional Design
On Lisp - Functions as Properties
On Lisp - How Macros Work
On Lisp - Iteration with Multiple Values
On Lisp - Macro Characters
On Lisp - Macros as Programs
On Lisp - Need for Macros
On Lisp - New Implementation
On Lisp - New Utilities (Computation at Compile-Time)
On Lisp - Non-functional Expanders
On Lisp - Objects in Plain Lisp
On Lisp - Operations on Lists
On Lisp - Other Structures
On Lisp - Recursion on Cdrs
On Lisp - Recursion on Cdrs (Macros Returning Functions)
On Lisp - Recursion on Subtrees
On Lisp - Referential Transparency
On Lisp - Scheme Continuations
On Lisp - Scheme Implementation
On Lisp - The Concept (Nondeterminism)
On Lisp - The Need for Nondeterminism
On Lisp - The Process Abstraction
On Lisp - The with- Macro
On Lisp - True Nondeterminism
On Lisp - When Capture Occurs
On Lisp - When Nothing Else Will Do
On Lisp - When What Happens
PCL - and more
PCL - and or and not
PCL - anonymous functions
PCL - basic formatting
PCL - beyond simple macros
PCL - combining recycling with shared structure
PCL - cond
PCL - condition handlers
PCL - conditional execution
PCL - conditional formatting
PCL - constructing new pathnames
PCL - cookies
PCL - defining a schema
PCL - destructuring bind
PCL - destructuring variables
PCL - detecting tag padding
PCL - do
PCL - dolist and dotimes
PCL - file output
PCL - fixing the return value
PCL - foo macros
PCL - foo special operators
PCL - formatting lisp code
PCL - hash tables
PCL - hello world lisp style
PCL - how the reader uses packages
PCL - id3 frames
PCL - implementing shoutcast
PCL - improving the user interaction
PCL - indenting printer
PCL - interacting with the file system
PCL - list manipulation functions
PCL - listing a directory
PCL - local flow of control
PCL - lookup tables alists and plists
PCL - manipulating the playlist
PCL - mixing different parameter types
PCL - multiple values
PCL - optional parameters
PCL - other database operations
PCL - other kinds of io
PCL - other method combinations
PCL - other structures
PCL - other uses for conditions
PCL - other ways to modify places
PCL - playlists as song sources
PCL - providing multiple restarts
PCL - query parameter types
PCL - query parameters
PCL - querying the database
PCL - querying the database
PCL - reading file data
PCL - refactoring
PCL - restarts
PCL - running the app
PCL - s expressions as lisp forms
PCL - sequence iterating functions
PCL - sequence predicates
PCL - sets
PCL - special operators
PCL - string comparisons
PCL - subsequence manipulations
PCL - termination tests
PCL - testing a files existence
PCL - text information frames
PCL - the compiler
PCL - the format function
PCL - the heart of a spam filter
PCL - the implementation
PCL - the playlist
PCL - the pretty printer backend
PCL - the public api
PCL - there is no list
PCL - training the filter
PCL - trees
PCL - truth falsehood and equality
PCL - two first tries
PCL - two representations of directory names
PCL - variable basics
PCL - vectors
PCL - walking a directory tree
PCL - when and unless
Successful Lisp - chapter04
Successful Lisp - chapter12
Successful Lisp - lesson 4
Successful Lisp - lesson 8
(unless test &body forms)
Function: If the first argument is not true, the rest of the forms are evaluated as a PROGN.
Example:
(defun file-pathname-p (p)
  (unless (directory-pathname-p p) p))
Mentioned in:
CLtL2 - 24.1. General Error-Signaling Functions
CLtL2 - 26.10. Conditional Execution
CLtL2 - 26.3.2. Kinds of Loop Clauses
CLtL2 - 6. Predicates
CLtL2 - 6.4. Logical Operators
CLtL2 - 7. Control Structure
CLtL2 - 7.10.2. Rules Governing the Passing of Multiple Values
CLtL2 - 7.6. Conditionals
HyperSpec - Macro WHEN, UNLESS
On Lisp - Adding Prolog Features
On Lisp - Chapter _28
On Lisp - New Utilities (Computation at Compile-Time)
On Lisp - Objects in Plain Lisp
On Lisp - Referential Transparency
PCL - and or and not
PCL - the mighty loop
PCL - when and unless

By Bill Moorier