System command

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System commands provide services or information associated with the workspace and the environment. They are not part of the APL language itself.

APL system commands start with a right parenthesis, e.g., )save, )pcopy.

List of system commands

ISO/IEC 13751:2001

ISO/IEC 13751:2001 standard defined the following system commands:[1]

Command Description
)CLEAR Clear active workspace.
)COPY Copy library workspace / Copy library workspace object.
)DROP Drop library workspace.
)ERASE Erase global referent.
)FNS Lists global function names.
)LIB List library directory.
)LOAD Load library workspace.
)NMS List global names and their name class.
)OPS List global operator names.
)SAVE Save active workspace / Save active workspace with name.
)SI List state indicator.
)SIC Clear state indicator.
)SINL List state indicator and local names.
)VARS List global variable names.
)WSID List workspace identification / Change workspace identification.

Dyalog APL

Dyalog APL supports the following system commands:

Command Description
)classes Lists the APL classes in the active workspace.
)clear Clear the workspace.
)cmd {Y} Executes an operating system command; equivalent to )sh.
)continue Saves the active workspace as Continue and terminate APL.
)copy {Y} Copies all or selected objects from a saved workspace into the active workspace.
)cs {Y} Change current namespace.
)drop {Y} Deletes a named workspace.
)ed Y Opens an object in the editor.
)erase Y Deletes objects from the active workspace.
)events Lists the events that the current GUI namespace may generate.
)fns {Y} Lists global functions in the active workspace.
)holds Lists the tokens acquired or requested by :Hold.
)interfaces List the currently active interfaces.
)lib {Y} Lists all available workspaces or workspaces in a directory Y.
)load {Y} Replace the active workspace by a saved workspace.
)methods List methods in GUI namespace or object.
)ns {Y} Create a global namespace / Query the name of the current namespace.
)obs {Y} List the global namespaces in the active workspace. Synonym: )objects {Y}.
)off Terminate APL immediately.
)ops {Y} Lists global operators in the active workspace.
)pcopy {Y} Protected copy. Similar to )copy, but does not overwrite existing objects.
)props List properties of GUI namespace or object.
)reset Clears the execution stack (Reset the state indicator).
)save {Y} Saves the active workspace to disk.
)sh {Y} Executes an operating system command; equivalent to )cmd.
)si State Indicator.
)sic Clear State Indicator.
)sinl State Indicator with local Name List.
)tid {Y} Switches to suspended thread, or lists the current thread number.
)vars {Y} Lists global variables in the active workspace.
)wsid {Y} Query / Set the identity of the active workspace.
)xload Y Load a workspace without executing its Latent Expression (⎕LX).

External links




  1. BS ISO/IEC 13751:2001: Information technology. Programming languages, their environments and system software interfaces. Programming language Extended APL. (2001).

APL syntax [edit]
General Comparison with traditional mathematicsPrecedenceTacit programming
Array Numeric literalStringStrand notationObject literalArray notation
Function ArgumentFunction valenceDerived functionDerived operatorNiladic functionMonadic functionDyadic functionAmbivalent functionTradfnDfnFunction train
Operator OperandOperator valenceTradopDopDerived operator
Assignment MultipleIndexedSelectiveModified
Other Function axisBranchQuad nameSystem commandUser commandKeywordDot notationFunction-operator overloading