System Functions Categorised

The following tables list the system functions divided into appropriate categories.

Settings Affecting Behaviour of Primitive Functions

Name	Description
`⎕CT`	Comparison Tolerance
`⎕DCT`	Decimal Comp Tolerance
`⎕DIV`	Division Method
`⎕FR`	Floating-Point Representation
`⎕IO`	Index Origin
`⎕ML`	Migration Level
`⎕PP`	Print Precision
`⎕RL`	Random Link

The following table describes the dependencies that exist between functions, operators and these system variables.

Table 1: Implicit Arguments
System Variable	Monadic Functions	Dyadic Functions	Operators
`⎕CT, ⎕DCT`	`⌈ ⌊ ∪`	`~ < ≤ = ≥ > ≠ ≡ ≢ ⍳ ∊ ∪ ∩ ⍷ \| ∨ ∧`	`⌸`
`⎕DIV`	`÷`	`÷`
`⎕FR ⍝ 1`	`÷ * ⍟ ! ○ ⌹`	`+ - × ÷ * ⍟ \| ! ○ ∨ ∧ ⊥ ⊤ ⌹`
`⎕FR ⍝ 2`	`⌈ ⌊ ∪`	`~ < ≤ = ≥ > ≠ ≡ ≢ ⍳ ∊ ∪ ∩ ⍷`	`⌸`
`⎕FR ⍝ 3`	`⍒ ⍋`	`⌈ ⌊ ⍒ ⍋ ⍸`
`⎕IO`	`⍳ ? ⍒ ⍋ ⍸`	`⍳ ? ⍒ ⍋ ⍉ ⊃ ⌷ ⍸`	`⌸ @ []`
`⎕ML`	`∊ ↑ ⊃ ≡`
`⎕PP`	`⍕`
`⎕RL`	`?`	`?`

where, for ⎕FR, 1 indicates functions that compute real numbers and whose precision depends on ⎕FR, 2 indicates functions that perform tolerant comparisons and 3 indicates functions that perform tolerant comparisons.

Note

Tolerant comparisons depend on ⎕FR to select which of ⎕CT and ⎕DCT is used; ⎕FR also determines the precision of the comparison computation that can affect results. However, even primitives involving intolerant comparison (including the tolerant ones with all comparison tolerances set to 0) can depend on ⎕FR if the argument contains DECFs. This is because DECFs must be converted to doubles for comparison. If two DECFs are different but correspond to the same double, then they will be treated as intolerantly unequal when ⎕FR is 1287 but equal when it is 645.

Session Information/Management

Name	Description
`⎕AI`	Account Information
`⎕AN`	Account Name
`⎕CLEAR`	Clear workspace (WS)
`⎕CY`	Copy objects into active WS
`⎕DL`	Delay execution
`⎕LOAD`	Load a saved WS
`⎕OFF`	End the session
`⎕PATH`	Search Path
`⎕SAVE`	Save the active WS
`⎕TS`	Timestamp

System Constants

Name	Description
`⎕A`	Alphabetic upper case characters
`⎕D`	Digits
`⎕NULL`	Null Item

Tools and Access to External Utilities

Name	Description
`⎕C`	Case Convert
`⎕CMD`	Execute the Windows Command Processor or another program
`⎕CMD`	Start a Windows AP
`⎕CSV`	Comma Separated Values
`⎕DR`	Data Representation (Monadic)
`⎕DR`	Data Representation (Dyadic)
`⎕DT`	Datetime
`⎕FMT`	Resolve display
`⎕FMT`	Format array
`⎕JSON`	JSON Convert
`⎕MAP`	Map a file
`⎕NA`	Declare a DLL function
`⎕R`	Replace
`⎕S`	Search
`⎕SH`	Execute a UNIX command or another program
`⎕SH`	Start a UNIX AP
`⎕SHELL`	Execute a shell command or another program
`⎕UCS`	Unicode Convert
`⎕USING`	Microsoft .NET Search Path
`⎕VFI`	Verify and Fix numeric
`⎕XML`	XML Convert

Manipulating Functions and Operators

Name	Description
`⎕AT`	Object Attributes
`⎕CR`	Canonical Representation
`⎕ED`	Edit one or more objects
`⎕EX`	Expunge objects
`⎕FX`	Fix definition
`⎕LOCK`	Lock a function
`⎕MONITOR`	Monitor set
`⎕MONITOR`	Monitor query
`⎕OR`	Object Representation
`⎕NR`	Nested Representation
`⎕PROFILE`	Profile Application
`⎕REFS`	Local References
`⎕STOP`	Set Stop vector
`⎕STOP`	Query Stop vector
`⎕TRACE`	Set Trace vector
`⎕TRACE`	Query Trace vector
`⎕VR`	Vector Representation

Namespaces and Objects

Name	Description
`⎕BASE`	Base Class
`⎕CLASS`	Class
`⎕CS`	Change Space
`⎕DF`	Display Format
`⎕FIX`	Fix
`⎕INSTANCES`	Instances
`⎕NEW`	New Instance
`⎕NS`	Namespace
`⎕SRC`	Source
`⎕THIS`	This

Input and Output

Name	Description
`⎕`	Evaluated Input/Output
`⍞`	Character Input/Output
`⎕ARBIN`	Arbitrary Input
`⎕ARBOUT`	Arbitrary Output
`⎕RTL`	Response Time Limit

Component Files

Name	Description
`⎕FAPPEND`	Append a component to File
`⎕FAVAIL`	File system Availability
`⎕FCHK`	File Check and Repair
`⎕FCOPY`	Copy a File
`⎕FCREATE`	Create a File
`⎕FDROP`	Drop a block of components
`⎕FERASE`	Erase a File
`⎕FHIST`	File History
`⎕FHOLD`	File Hold
`⎕FLIB`	List File Library
`⎕FNAMES`	Names of tied Files
`⎕FNUMS`	Tie Numbers of tied Files
`⎕FPROPS`	File Properties
`⎕FRDAC`	Read File Access matrix
`⎕FRDCI`	Read Component Information
`⎕FREAD`	Read a component from File
`⎕FRENAME`	Rename a File
`⎕FREPLACE`	Replace a component on File
`⎕FRESIZE`	File Resize
`⎕FSIZE`	File Size
`⎕FSTAC`	Set File Access matrix
`⎕FSTIE`	Share-Tie a File
`⎕FTIE`	Tie a File exclusively
`⎕FUNTIE`	Untie Files

Native Files

Name	Description
`⎕MKDIR`	Create a directory
`⎕NAPPEND`	Append to File
`⎕NCOPY`	Copy files and directories
`⎕NCREATE`	Create a File
`⎕NDELETE`	Delete a File or Directory
`⎕NERASE`	Erase a File
`⎕NEXISTS`	Discover whether or not a file or directory exists
`⎕NGET`	Read Text File
`⎕NINFO`	Query or set information about one or more files and/or directories
`⎕NLOCK`	Lock a region of a file
`⎕NMOVE`	Move files and directories
`⎕NNAMES`	Names of tied Files
`⎕NNUMS`	Tie Numbers of tied Files
`⎕NPARTS`	Split a file name into its constituent parts.
`⎕NPUT`	Write Text File
`⎕NREAD`	Read from File
`⎕NRENAME`	Rename a File
`⎕NREPLACE`	Replace data on File
`⎕NRESIZE`	File Resize
`⎕NSIZE`	File Size
`⎕NTIE`	Tie a File exclusively
`⎕NUNTIE`	Untie Files
`⎕NXLATE`	Specify Translation Table

Threads

Name	Description
`⎕TALLOC`	Allocate Token Range
`⎕TCNUMS`	Thread Child Numbers
`⎕TID`	Current Thread Identity
`⎕TKILL`	Kill Threads
`⎕TNAME`	Current Thread Name
`⎕TNUMS`	Thread Numbers
`⎕TSYNC`	Wait for Threads to Terminate

Synchronisation

Name	Description
`⎕TALLOC`	Allocate Token Range
`⎕TGET`	Get Tokens
`⎕TKILL`	Kill Threads
`⎕TPOOL`	Token Pool
`⎕TPUT`	Put Tokens
`⎕TREQ`	Token Requests

Error Handling

Name	Description
`⎕DM`	Diagnostic Message
`⎕DMX`	Extended Diagnostic Message
`⎕EM`	Event Messages
`⎕EN`	Event Number
`⎕EXCEPTION`	Reports the most recent Microsoft .NET Exception
`⎕SIGNAL`	Signal event
`⎕TRAP`	Event Trap

Stack and Workspace Information

Name	Description
`⎕LC`	Line Count
`⎕LX`	Latent Expression
`⎕NC`	Name Classification
`⎕NL`	Name List
`⎕NSI`	Namespace Indicator
`⎕RSI`	Space Indicator
`⎕SI`	State Indicator
`⎕SHADOW`	Shadow names
`⎕SIZE`	Size of objects
`⎕STACK`	Report Stack
`⎕STATE`	Return State of an object
`⎕VGET`	Value Get
`⎕VSET`	Value Set
`⎕WA`	Workspace Available
`⎕WSID`	Workspace Identification
`⎕XSI`	Extended State Indicator

Shared Variables

Name	Description
`⎕SVC`	Set access Control
`⎕SVC`	Query access Control
`⎕SVO`	Shared Variable Offer
`⎕SVO`	Query degree of coupling
`⎕SVQ`	Shared Variable Query
`⎕SVR`	Retract offer
`⎕SVS`	Query Shared Variable State

GUI and COM Support

Name	Description
`⎕DQ`	Await and process events
`⎕EXPORT`	Export objects
`⎕NQ`	Place an event on the Queue
`⎕WC`	Create GUI object
`⎕WG`	Get GUI object properties
`⎕WN`	Query GUI object Names
`⎕WS`	Set GUI object properties
`⎕WX`	Expose GUI property names

Miscellaneous

Name	Description
`⎕Ⓐ`	Underscored Alphabetic Characters
`⎕AV`	Atomic Vector
`⎕AVU`	Atomic Vector - Unicode
`⎕KL`	Key Labels
`⎕PFKEY`	Programmable Function Keys
`⎕SD`	Screen Dimensions
`⎕SM`	Screen Map
`⎕SR`	Screen Read
`⎕OPT`	Variant Operator
`⎕TC`	Terminal Control
`⎕XT`	Associate External variable
`⎕XT`	Query External variable

System Variables

System variables retain information used by the system in some way. Many system variables affect the behaviour of primitive functions and operators to which they act as implicit arguments.

System variables can be localised by inclusion in the header line of a defined function or in the argument list of the system function ⎕SHADOW. When a system variable is localised, it retains its previous value until it is assigned a new one. This feature is known as "pass-through localisation". The exception to this rule is ⎕TRAP.

A system variable can never be undefined. Default values are assigned to all system variables in a clear workspace.

Name	Description	Scope
`⎕AVU`	Atomic Vector – Unicode	Namespace
`⎕CT`	Comparison Tolerance	Namespace
`⎕DCT`	Decimal Comp Tolerance	Namespace
`⎕DIV`	Division Method	Namespace
`⎕FR`	Floating-Point Representation	Namespace
`⎕IO`	Index Origin	Namespace
`⎕LX`	Latent Expression	Workspace
`⎕ML`	Migration Level	Namespace
`⎕PATH`	Search Path	Session
`⎕PP`	Print Precision	Namespace
`⎕PW`	Print Width	Session
`⎕RL`	Random Link	Namespace
`⎕RTL`	Response Time Limit	Namespace
`⎕SM`	Screen Map	Workspace
`⎕TNAME`	Thread Name	Workspace
`⎕TRAP`	Event Trap	Workspace
`⎕USING`	Microsoft .NET Search Path	Namespace
`⎕WSID`	Workspace ID	Workspace
`⎕WX`	Window Expose	Namespace

In other words, ⎕PATH and ⎕PW relate to the session. ⎕LX, ⎕SM, ⎕TRAP, and ⎕WSID relate to the active workspace. All the other system variables relate to the current namespace.

Session	Workspace	Namespace
`⎕PATH`	`⎕LX`	`⎕AVU`
`⎕PW`	`⎕SM`	`⎕CT`
	`⎕TRAP`	`⎕DCT`
	`⎕WSID`	`⎕DIV`
		`⎕FR`
		`⎕IO`
		`⎕ML`
		`⎕PP`
		`⎕RL`
		`⎕RTL`
		`⎕USING`
		`⎕WX`

Note that the value assigned to a system variable must be appropriate, otherwise an error will be reported immediately.

Example

      ⎕IO←3
DOMAIN ERROR
      ⎕IO←3
      ^