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"Learn APL" Notes

(luksamuk.codes)

49 points

by todsacerdoti2 days ago |
10 comments
upvoteby smartmic2 days ago|
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I worked with GNU APL for a while and really liked it. It's also possible to extend it with the C foreign function interface (FFI). The best way I found to input the APL2 symbols with my normal keyboard was with a customized XCompose definition where the input chords are mnemonics of the actual symbols: https://gist.github.com/smartmic/cdb8b0b3936ab965213748813b6...
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upvoteby turtleyacht2 days ago|
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Thank-you. Any thoughts on the layout below versus the others listed?

https://www.pckeyboard.com/page/product/USAPLSET

I've got some notes on setting up input on OpenBSD as well. It enables Left Ctrl and Left Alt for APL symbols, but also a Unicode escape hatch with Right Alt and Caps Lock: https://github.com/turtleyacht/ap-el-kb.github.io

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upvoteby ofalkaed2 days ago|
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It looks to be the standard Dyalog APL keyset, which will be just fine for GnuAPL and most if not all APLs but not all languages of the APL family.
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upvoteby bear86422 days ago|
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huh, can you not use the Xkb APL symbols file?

I thought that compose definitions as well as the shifted layout…

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upvoteby ofalkaed2 days ago|
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You can and most do but some people go other routes for one reason or another.

https://aplwiki.com/wiki/Typing_glyphs

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upvoteby throwaway815231 days ago|
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Old RMS song, to the tune of "row row row your boat":

Rho, rho, rho of x, always equals 1

Rho's dimension, rho rho rank; APL is fun!

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upvoteby mmooss2 days ago|
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APL was developed in the 1960s. Between then and whenever its symbols were added to Unicode (U+2336 and following, at least), how were its symbols encoded?
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upvoteby 2 days ago|
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deleted
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upvoteby 7thaccount2 days ago|
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Early on, the selectric typewriter thing had a spherical ball that could rotate to stamp the characters. So when you typed a key the IBM hardware would type a character on a piece of paper exactly like a typewriter and also the IBM computer would keep track of this and when you ran the expression it would calculate the result and print that out as well. You can see videos of this.
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upvoteby dzaima2 days ago|
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Custom encodings, as was standard (or, well, mandatory) before Unicode (1991). Hell, Dyalog APL to this day supports its classic 1-byte-per-char encoding (not even ASCII-compatible! Nor EBCDIC!) in addition to Unicode.

Looks like the APL chars were added in Uncicode 1.1 (1993), two years after 1.0, which is quick enough.

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upvoteby electroly2 days ago|
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I believe it depends on the era and system, but there were various APL codepages (i.e. definitions for the upper 128 characters) for both EBCDIC and ASCII.

https://en.wikipedia.org/wiki/Digital_encoding_of_APL_symbol...

In the very earliest IBM Selectric teletype-based systems, some APL symbols were constructed by entering one character, hitting backspace, and overstriking a second character. For instance, ⍋ is | overstruck on ∆. It's why a lot of APL symbols look like that.

https://aplwiki.com/wiki/Overstrike

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