Editing APL (programming language) (section)

=== Character set ===
{{Main|APL (codepage)|APL syntax and symbols#Monadic functions|l2=syntax and symbols}}

APL has been criticized and praised for its choice of a unique character set. In the 1960s and 1970s, few terminal devices or even displays could reproduce the APL character set. The most popular ones employed the [[IBM Selectric]] print mechanism used with a special APL type element. One of the early APL [[computer terminal|line terminals]] (line-mode operation only, ''not'' full screen) was the Texas Instruments TI Model 745 ({{circa|1977}}) with the full APL character set<ref>{{cite journal |author1=Texas Instruments |title=TI 745 full page ad: Introducing a New Set of Characters |journal=Computerworld |date=1977 |volume=11 |issue=27 |page=32 |url=https://books.google.com/books?id=wMe6erbb5V4C&q=apl%20terminal%20%22texas%20instruments%22&pg=PA32 |access-date=January 20, 2015}}</ref> which featured [[Duplex (telecommunications)|half and full duplex]] [[telecommunications]] modes, for interacting with an APL [[time-sharing]] service or remote mainframe to run a remote computer job, [[remote job entry]] (RJE).

Over time, with the universal use of high-quality graphic displays, printing devices and [[Unicode]] support, the APL character font problem has largely been eliminated. However, entering APL characters requires the use of [[input method editor]]s, keyboard mappings, virtual/on-screen APL symbol sets,<ref name="FontsKeys">{{cite web |author1=<!-- Unstated --> |date=2004–2024 |title=APL Fonts and Keyboards |url=https://www.dyalog.com/apl-font-keyboard.htm |website=Dyalog, Ltd. |access-date=November 1, 2024}}</ref><ref>{{cite web |last1=Smith |first1=Bob |url=http://www.sudleyplace.com/APL/Keyboard.ahtml |title=NARS2000 Keyboard |website=www.sudleyplace.com |publisher=Bob Smith; NARS2000 |access-date=January 19, 2015}}</ref> or easy-reference printed keyboard cards which can frustrate beginners accustomed to other programming languages.<ref>{{cite web |title=Introduction to APL – APL Symbols |website=www.microapl.co.uk |publisher=MicroAPL Ltd |url=http://www.microapl.co.uk/apl/introduction_chapter1.html |access-date=January 8, 2015}}</ref><ref>{{cite journal |last1=Brown |first1=James A. |last2=Hawks |first2=Brent |last3=Trimble |first3=Ray |date=1993 |title=Extending the APL character set |journal=ACM SIGAPL APL Quote Quad |volume=24 |issue=1 |pages=41–46 |doi=10.1145/166198.166203}}</ref><ref>{{cite web |last1=Kromberg |first1=Morten |title=Unicode Support for APL |url=http://archive.vector.org.uk/art10500090 |website=archive.vector.org.uk |publisher=Vector, Journal of the British APL Association |access-date=January 8, 2015 |archive-url=https://web.archive.org/web/20150120194338/http://archive.vector.org.uk/art10500090|archive-date=January 20, 2015 |url-status=dead}}</ref> With beginners who have no prior experience with other programming languages, a study involving high school students found that typing and using APL characters did not hinder the students in any measurable way.<ref>{{cite web |last1=Hsu |first1=Aaron |title=Computer Science Outreach and Education with APL |url=http://video.dyalog.com/Dyalog13/?v=kIItfQJEVdM |publisher=Dyalog, Ltd. |access-date=July 15, 2016 |archive-date=August 17, 2016 |archive-url=https://web.archive.org/web/20160817061145/http://video.dyalog.com/Dyalog13/?v=kIItfQJEVdM |url-status=dead}}</ref>

In defense of APL, it requires fewer characters to type, and keyboard mappings become memorized over time. Special APL keyboards are also made and in use today, as are freely downloadable fonts for operating systems such as Microsoft Windows.<ref name="FontsKeys"/> The reported productivity gains assume that one spends enough time working in the language to make it worthwhile to memorize the symbols, their semantics, keyboard mappings, and many idioms for common tasks.{{citation needed|date=July 2015}}