Skip to content

Documentation

Downstile ⌊

Initializing search

Documentation

Release Notes
Release Notes
- v21.0 Release Notes
  v21.0 Release Notes
  - System Requirements
  - Announcements
    
    Announcements
    
    Deprecated Functionality
  - New and Enhanced Features
  - Minor Updates and Bug Fixes
  - Interoperability
- Earlier Release Notes
  Earlier Release Notes
  - v20.0 Release Notes
    
    v20.0 Release Notes
    
    System Requirements
    
    Announcements
    
    Announcements
    
    Deprecated Functionality
    
    New and Enhanced Features
    
    Minor Updates and Bug Fixes
    
    Interoperability
  - v19.0 Release Notes
    
    v19.0 Release Notes
    
    Introduction
    Introduction
    
    Key Features
    
    Extension to Native File Functions
    
    Lexical Scope in Scripts
    
    Session Gutter
    
    Source as Typed
    
    Bug Fixes
    
    Announcements
    
    System Requirements
    
    Interoperability
    
    Configuration Parameters
    Configuration Parameters
    
    New or Changed Configuration Parameters
    
    DYALOG_GUTTER_ENABLE
    
    DYALOG_DISCARD_FN_SOURCE
    
    DYALOG_INITSESSION
    
    DyalogLink
    
    DyalogStartup_X
    
    DyalogStartupSE
    
    Log_File
    
    Language Reference Changes
    Language Reference Changes
    
    Language Changes
    
    File Hold
    
    Fix Script
    
    Allocate Token Range
    
    Memory Manager Statistics
    
    Enable Compression of Large Components
    
    Discard Source Information
    
    Discard Source Code
    
    Hash Table Size
    
    Lookup Table Size
    
    Object Reference Changes
    Object Reference Changes
    
    AllowContextMenu
    
    ExecuteJavaScript
    
    GetZoomLevel
    
    IsLoading
    
    LoadEnd
    
    SetZoomLevel
Core Reference
Core Reference
- Dyalog APL Language
  Dyalog APL Language
- Programming
  Programming
  - Introduction
    Introduction
    
    Workspaces
    
    Legal Names
    
    Arrays
    Arrays
    
    Introduction
    
    Numbers
    
    Characters
    
    Enclosed Elements
    
    Specification of Variables
    
    Vector Notation
    
    Array Notation
    
    Structuring of Arrays
    
    Display of Arrays
    
    Prototypes and Fill Items
    
    Cells and Subarrays
    
    Expressions
    
    Output
    
    Functions
    
    Operators
    
    Results
    
    Binding Strength
    
    Function Trains
    
    Search Functions and Hash Tables
    
    Idiom Recognition
    Idiom Recognition
    
    Introduction
    
    Idiom List
    
    Parallel Execution
    
    Complex Numbers
    
    128 Bit Decimal Floating-Point Support
    
    Namespaces
    Namespaces
    
    Overview
    
    Namespace Syntax
    
    Namespace Reference Evaluation
    
    Namespaces and Localisation
    
    Namespace References
    
    Unnamed Namespaces
    
    Arrays of Namespace References
    
    Distributed Assignment
    
    Distributed Functions
    
    Namespaces and Operators
    
    Serialising Namespaces
    
    External Variables
    
    Component Files
    
    Auxiliary Processors
  - Deprecated Functionality
  - Defined Functions and Operators
    Defined Functions and Operators
    
    Introduction
    
    Traditional Functions and Operators
    Traditional Functions and Operators
    
    Introduction
    
    Model Syntax
    
    Statements
    
    Global & Local Names
    
    Locals Lines
    
    Namelists
    
    Locked Functions & Operators
    
    Function Declaration Statements
    Function Declaration Statements
    
    Introduction
    
    Access Statement
    
    Attribute Statement
    
    Implements Statement
    
    Signature Statement
    
    Control Structures
    Control Structures
    
    Introduction
    
    If Statement
    
    While Statement
    
    Repeat Statement
    
    For Statement
    
    Select Statement
    
    With Statement
    
    Hold Statement
    
    Trap Statement
    
    GoTo Statement
    
    Return Statement
    
    Leave Statement
    
    Continue Statement
    
    Section Statement
    
    Disposable Statement
    
    APL Line Editor
    
    Dfns and Dops
    Dfns and Dops
    
    Introduction
    
    Model Syntax
    
    Statements
    
    Multi-line Dfns
    
    Arguments and Operands
    
    Default Left Argument
    
    Guards
    
    Error Guards
    
    Shy Result
    
    Global and Local Names
    
    Lexical Name Scope
    
    Recursion
    
    Tail Calls
    
    Dops
    
    Restrictions
  - Object Oriented Programming
    Object Oriented Programming
    
    Introducing Classes
    Introducing Classes
    
    Introducing Classes
    
    Defining Classes
    
    Editing Classes
    
    Inheritance
    
    Instances
    
    Constructors
    Constructors
    
    Introduction
    
    Constructor Overloading
    
    Niladic (Default) Constructors
    
    Empty Arrays of Instances: Why?
    
    Empty Arrays of Instances: How?
    
    Base Constructors
    
    Niladic Example
    
    Monadic Example
    
    Destructors
    
    Class Members
    Class Members
    
    Introduction
    
    Fields
    Fields
    
    Introduction
    
    Public Fields
    
    Initialising Fields
    
    Private Fields
    
    Shared Fields
    
    Trigger Fields
    
    Methods
    Methods
    
    Methods
    
    Shared Methods
    
    Instance Methods
    
    Superseding Base Class Methods
    
    Properties
    Properties
    
    Properties
    
    Simple Instance Properties
    
    Simple Shared Properties
    
    Numbered Properties
    Numbered Properties
    
    Introduction
    
    Example
    
    The Default Property
    
    ComponentFile Class
    
    Keyed Properties
    Keyed Properties
    
    Introduction
    
    Example 1
    
    Example 2
    
    Interfaces
    Interfaces
    
    Introduction
    
    Example
    
    Including Namespaces in Classes
    Including Namespaces in Classes
    
    Introduction
    
    Example
    
    Nested Classes
    Nested Classes
    
    Nested Classes
    
    GolfService Example
    
    Namespace Scripts
    Namespace Scripts
    
    Namespace Scripts
    
    DiaryStuff Example
    
    Including Script Files
    
    Class Declaration Statements
    Class Declaration Statements
    
    Introduction
    
    Interface Statement
    
    Namespace Statement
    
    Class Statement
    
    Using Statement
    
    Attribute Statement
    
    Access Statement
    
    Implements Statement
    
    Field Statement
    
    Property Section
    Property Section
    
    Property Statement
    
    PropertyArguments Class
    
    PropertyGet Function Syntax
    
    PropertySet Function Syntax
    
    PropertyShape Function Syntax
  - Threads
    Threads
    
    Introduction
    
    Multi-Threading Language Elements
    
    Thread Switching
    
    Name Scope
    
    Stack Considerations
    
    Globals and the Order of Execution
    
    Threads & Niladic Functions
    
    Threads & External Functions
    
    Synchronising Threads
    
    Semaphore Example
    
    Latch Example
    
    Debugging
  - Triggers
    Triggers
    
    Introduction
    
    Example
    
    Global Triggers
  - Native Files
  - Component Files
    Component Files
    
    Introduction
    
    Component Files
    
    Programming Techniques
    
    File Design
    
    Internal Structure
    
    The Effect of Buffering
    
    Integrity and Security
  - Error Trapping
    Error Trapping
    
    Standard Error Action
    
    Error Trapping
    
    Error Trapping Examples
    
    Signalling Events
    
    Handling Unexpected Errors
  - Error Messages
    Error Messages
    
    Introduction
    
    APL Error Messages
    
    Operating System Error Messages
    
    Windows Operating System Error Messages
    
    APL Error Messages (A-Z)
    APL Error Messages (A-Z)
    
    bad ws
    
    cannot create name
    
    clear ws
    
    copy incomplete
    
    DEADLOCK
    
    defn error
    
    DOMAIN ERROR
    
    EOF INTERRUPT
    
    EXCEPTION
    
    FIELD CONTENTS RANK ERROR
    
    FIELD CONTENTS TOO MANY COLUMNS
    
    FIELD POSITION ERROR
    
    FIELD CONTENTS TYPE MISMATCH
    
    FIELD TYPE BEHAVIOUR UNRECOGNISED
    
    FIELD ATTRIBUTES RANK ERROR
    
    FIELD ATTRIBUTES LENGTH ERROR
    
    FULL SCREEN ERROR
    
    KEY CODE UNRECOGNISED
    
    KEY CODE RANK ERROR
    
    KEY CODE TYPE ERROR
    
    FORMAT FILE ACCESS ERROR
    
    FORMAT FILE ERROR
    
    FILE ACCESS ERROR
    
    FILE ACCESS ERROR CONVERTING
    
    FILE COMPONENT DAMAGED
    
    FILE DAMAGED
    
    FILE FULL
    
    FILE INDEX ERROR
    
    FILE NAME ERROR
    
    FILE NAME QUOTA USED UP
    
    FILE SYSTEM ERROR
    
    FILE SYSTEM NO SPACE
    
    FILE SYSTEM NOT AVAILABLE
    
    FILE SYSTEM TIES USED UP
    
    FILE TIE ERROR
    
    FILE TIED
    
    FILE TIED REMOTELY
    
    FILE TIE QUOTA USED UP
    
    FORMAT ERROR
    
    HOLD ERROR
    
    incorrect command
    
    INDEX ERROR
    
    INTERNAL ERROR
    
    INTERRUPT
    
    is name
    
    LENGTH ERROR
    
    LIMIT ERROR
    
    NONCE ERROR
    
    NO PIPES
    
    name is not a ws
    
    Name already exists
    
    Namespace does not exist
    
    not copied name
    
    not found name
    
    not saved this ws is name
    
    PROCESSOR TABLE FULL
    
    RANK ERROR
    
    RESIZE
    
    name saved date time
    
    SYNTAX ERROR
    
    sys error number
    
    TIMEOUT
    
    TRANSLATION ERROR
    
    TRAP ERROR
    
    too many names
    
    VALUE ERROR
    
    warning duplicate label
    
    warning duplicate name
    
    warning pendent operation
    
    warning label name present
    
    warning unmatched brackets
    
    warning unmatched parentheses
    
    was name
    
    WS FULL
    
    ws not found
    
    ws too large
    
    Operating System Error Messages (A-Z)
    Operating System Error Messages (A-Z)
    
    FILE ERROR 1 Not owner
    
    FILE ERROR 2 No such file
    
    FILE ERROR 5 I O error
    
    FILE ERROR 6 No such device
    
    FILE ERROR 13 Permission denied
    
    FILE ERROR 20 Not a directory
    
    FILE ERROR 21 Is a directory
    
    FILE ERROR 23 File table overflow
    
    FILE ERROR 24 Too many open
    
    FILE ERROR 26 Text file busy
    
    FILE ERROR 27 File too large
    
    FILE ERROR 28 No space left
    
    FILE ERROR 30 Read only file
    
    System Errors
  - APLMon
    APLMon
    
    Introduction
    
    Using APLMON
    
    APLMON output
    
    Special syntax
    
    Notes
Code Tooling
Code Tooling
- .NET Interface
  .NET Interface
  - Installation
  - .NET Classes
    
    .NET Classes
    
    Locating .NET Classes and Assemblies
    
    Using .NET Classes
    
    Advanced Techniques
    
    Example Usage
    
    Enumerations
    
    Handling Pointers with Dyalog.ByRef
    
    DECF Conversion
  - APL Source Files
  - Writing .NET Classes
    
    Writing .NET Classes
    
    Assemblies, Namespaces, and Classes
    
    Tutorial
    
    Interfaces
    
    Creating .NET Classes with APL Source Files
- Compiler
  Compiler
- Shared Code Files
  Shared Code Files
  - Introduction
    
    Introduction
    
    Benefits Offered by Shared Code Files
    
    Limitations
  - Performance
  - Technical Details
  - Worked Example
Dyalog for Microsoft Windows
Dyalog for Microsoft Windows
Dyalog for UNIX
Dyalog for UNIX
- Installation/Configuration
  Installation/Configuration
  - Introduction
  - Installing Dyalog APL
  - Dyalog Serial Number
  - Konsole
  - APL VNC RDP
  - PuTTY
  - Configuration Parameters
    Configuration Parameters
    
    Introduction
    
    Configuration Files
    
    Environment Variables
  - Configuring the Editor
  - Starting APL from scripts
  - Magic
  - SE and SALT
  - HOME dyalog directory
  - QuadNA and UNIX
  - Miscellaneous
  - BuildID
- User Interface
  User Interface
About
About

Downstile `⌊`

Monadic Downstile means Floor

      ⌊ 3.4 ¯3.4 3 0
3 ¯4 3 0

Dyadic Downstile means Minimum

      1.1 ¯2 ⌊ 8.1 ¯3.4
1.1 ¯3.4

      ⌊/ 3 1 4 1
1

Language Elements

Made with Material for MkDocs
Copyright © 1982-2026 Dyalog Limited (2026-08-07 main:ca6640ec79).
Except where otherwise noted, content on this site is licensed under a Creative Commons Attribution 4.0 International licence.