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APL2 was a significant re-implementation of APL by IBM which was developed from 1971 and first released in 1984. It provided many additions to the language, of which the most notable is nested (non-rectangular) array support. It was available for mainframe computers running z/OS or z/VM and workstations running AIX, Linux, Sun Solaris, and Microsoft Windows.

APL2's extensions to ISO 8485:1989 were standardised as ISO-IEC-13751. APL2 supports entry of complex numbers in the following forms:

  1. Real and imaginary part separated by the letter J and no spaces, e.g. 0J1
  2. Magnitude and angle in degrees separated by the letter D and no spaces, e.g. 1D90
  3. Magnitude and angle in radians separated by the letter R and no spaces, e.g. 1R1.5708

No further core language features have been added, with improvements instead consisting of powerful Quad names.

The entire APL2 Products and Services Team was awarded the Iverson Award in 2007.

On January 26, 2021, IBM announced that IBM APL2 would be removed from the market on April 7, 2021, while support would continue until September 15, 2021, without the possibility of extension. Customers were advised to use Log-On APL2, which comes with a support option, as a replacement product.[1] Log-On APL2 will be distributed by the American-Israeli IBM business partner Log-On Software. It is advertised as fully compatible with APL2, and is scheduled for release on April 7, 2021.[2]

As of November 2021, Log-On has been able to build APL2 from IBM's sources, and is undergoing extensive testing. The next planned step is getting community and user feedback for desired features, and publication of re-branded documentation.[3] On April 19, 2022, Log-On announced the general availability of APL2 version 3.03 for workstations, which introduced support for HTTPS websites and Windows 11.[4]


  1. IBM. Software withdrawal and support discontinuance: IBM APL2, IBM APL2 Application Environment, and IBM Workstation APL2 for Multiplatforms. IBM Europe Withdrawal Announcement ZP21-0096. January 26, 2021.
  2. Mark Schora. Log-On Software Announces Log-On APL2. Log-On Press Releases. Jan 26, 2021.
  3. Werner Zülli. Log-On APL2: Plans and Questions. GSE Herbsttagung 2021. APL Germany.
  4. Mark Neeman (Log-On Software Director Products Sales). Log-On APL2 GA v. 3.03. Email to the APL2 community. Apr 19, 2022.
APL dialects [edit]
Maintained APL+WinAPL2APL64APL\ivApletteAprilCo-dfnsDyalog APLDyalog APL Visiondzaima/APLGNU APLKapNARS2000Pometo
Historical A Programming LanguageA+ (A) ∙ APL#APL\360APL/700APL\1130APL\3000APL.68000APL*PLUSAPL.jlAPL.SVAPLXExtended Dyalog APLIverson notationIVSYS/7090NARSngn/aplopenAPLOperators and FunctionsPATRowanSAXSHARP APLRationalized APLVisualAPL (APLNext) ∙ VS APLYork APL
Derivatives AHPLBQNCoSyELIGleeIIvyJJellyK (Goal, Klong, Q) ∙ KamilaLispLang5LilNialRADUiua
Overviews Comparison of APL dialectsTimeline of array languagesTimeline of influential array languagesFamily tree of array languages