4 ms·
When I was a young lad, the ink on my EE degree still wet, I worked with an older gentleman with a PhD, who used APL on an exotic computer with what looked to m
by sizzzzlerz 7y ago
When I was a young lad, the ink on my EE degree still wet, I worked with an older gentleman with a PhD, who used APL on an exotic computer with what looked to me like Sanskrit symbols (or space alien, for all I knew) on the keys. He gave me a couple tutorials but I never could wrap my brain around it. I lost interest and hadn't heard anything about APL for decades until now.
I am curious how the symbols used in the language are mapped onto a standard keyboard. Also, does anyone use APL in battle or is it mostly an academic toy?
- Vivtek 7y agoLanguages descended from APL are very popular among the financial engineering set.
- xvilka 7y agoDo you have any examples or links to confirm that?
- risubramanian 7y agoCheck out K, Q, and KDB
- frostburg 7y agoA similar language is used for kdb+.
- andylynch 7y agoParent is almost certainly referring to KDB https://kx.com/ https://kx.com/
- jjtheblunt 7y agolook up arthur whitney and kx.com, and their Q language for their kdb+ database. Various opensource versions are active.
- Volt 7y agoThere's no open source version of kdb+.
- coldtea 7y agoThey are used (K and such). "Very popular" they are not.
- ncmncm 7y agoI visited a top floor of Goldman Sachs in the early 90s. They were using J, a dialect of APL. They still had those dumb little Bloomberg cube terminals on their desks, with the angry-fruit-salad colors scheme. Nowadays it's in a window, but it looks the same. I don't know if they still use J, or K, but anyway not in real-time. That happens on FPGAs in a rack where traders once roamed. But while APL cannot be said to be very popular, the most popular "time-series database" used in finance is published by APL fananics.
- achamayou 7y agoNo they don't, GS strats have overwhelmingly used Slang/SecDB for many years now.
- ncmncm 7y agoI have had no contact with GS for 25 years, but KDB is unaccountably popular in other places on the Street. The specialized time-series database lost much of its reason to exist when disk seek times went to zero. Nowadays you stage onto an SSD, and spool to rotating storage later, if at all.
- achamayou 7y agoThey vastly exaggerate their popularity, helped by the lack of publicly available information. The number of quants writing q is dwarfed by those writing Python, Scala or even Slang. First Derivatives’ revenue last FY was ~200m and their pre-tax profit is ~17m. To say that they are unaccountably popular on the Street is quite an overstatement.
- ncmncm 7y ago
- kd0amg 7y agoFor coding in APL, I just switch to an alternate keymapping (Dyalog has one available for free).
- lelf 7y ago> how the symbols used in the language are mapped onto a standard keyboard It’s more-or-less standard mapping (across APL implementations) $ apl ]keyb US Keyboard Layout: ╔════╦════╦════╦════╦════╦════╦════╦════╦════╦════╦════╦════╦════╦═════════╗ ║ ~ ║ !⌶ ║ @⍫ ║ #⍒ ║ $⍋ ║ %⌽ ║ ^⍉ ║ &⊖ ║ *⍟ ║ (⍱ ║ )⍲ ║ _! ║ +⌹ ║ ║ ║ `◊ ║ 1¨ ║ 2¯ ║ 3< ║ 4≤ ║ 5= ║ 6≥ ║ 7> ║ 8≠ ║ 9∨ ║ 0∧ ║ -× ║ =÷ ║ BACKSP ║ ╠════╩══╦═╩══╦═╩══╦═╩══╦═╩══╦═╩══╦═╩══╦═╩══╦═╩══╦═╩══╦═╩══╦═╩══╦═╩══╦══════╣ ║ ║ Q ║ W⍹ ║ E⋸ ║ R ║ T⍨ ║ Y¥ ║ U ║ I⍸ ║ O⍥ ║ P⍣ ║ {⍞ ║ }⍬ ║ |⊣ ║ ║ TAB ║ q? ║ w⍵ ║ e∈ ║ r⍴ ║ t∼ ║ y↑ ║ u↓ ║ i⍳ ║ o○ ║ p⋆ ║ [← ║ ]→ ║ \⊢ ║ ╠═══════╩═╦══╩═╦══╩═╦══╩═╦══╩═╦══╩═╦══╩═╦══╩═╦══╩═╦══╩═╦══╩═╦══╩═╦══╩══════╣ ║ (CAPS ║ A⍶ ║ S ║ D ║ F ║ G ║ H ║ J⍤ ║ K ║ L⌷ ║ :≡ ║ "≢ ║ ║ ║ LOCK) ║ a⍺ ║ s⌈ ║ d⌊ ║ f_ ║ g∇ ║ h∆ ║ j∘ ║ k' ║ l⎕ ║ ;⍎ ║ '⍕ ║ RETURN ║ ╠═════════╩═══╦╩═══╦╩═══╦╩═══╦╩═══╦╩═══╦╩═══╦╩═══╦╩═══╦╩═══╦╩═══╦╩═════════╣ ║ ║ Z ║ Xχ ║ C¢ ║ V ║ B£ ║ N ║ M ║ <⍪ ║ >⍙ ║ ?⍠ ║ ║ ║ SHIFT ║ z⊂ ║ x⊃ ║ c∩ ║ v∪ ║ b⊥ ║ n⊤ ║ m| ║ ,⍝ ║ .⍀ ║ /⌿ ║ SHIFT ║ ╚═════════════╩════╩════╩════╩════╩════╩════╩════╩════╩════╩════╩══════════╝