Mnemonics: Difference between revisions

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<source lang=apl inline>⌹</source> is [[matrix divide]] with a <source lang=apl inline>⎕</source> symbolising a matrix and an inscribed <source lang=apl inline>÷</source> for "divide".
<source lang=apl inline>⌹</source> is [[matrix divide]] with a <source lang=apl inline>⎕</source> symbolising a matrix and an inscribed <source lang=apl inline>÷</source> for "divide".
<source lang=apl inline>?</source> symbolises the unknown, and thus [[roll]]s dice and [[deal]]s cards randomly.
<source lang=apl inline>⍺</source> and <source lang=apl inline>⍵</source> are the leftmost and rightmost letters of the [[wikipedia:Greek alphabet|Greek alphabet]].
<source lang=apl inline>∊</source> is the Greek letter [[Epsilon]] which corresponds to the letter **E** for [[Enlist]] and [[Element of]].
<source lang=apl inline>∊</source> is the Greek letter [[Rho]] which corresponds to the letter **R** for [[Reshape]].
<source lang=apl inline>∊</source> is [[Not]] when monadic, but its dyadic form, [[Without]] can also be remembered as ''but not''.
<source lang=apl inline>⍺</source> is the right-most letter of the [[wikipedia:Greek alphabet|Greek alphabet]].


<source lang=apl inline>⎕</source> is the prefix for all [[system name]]s, and also also manages input from the console as well as output to the console. For that, it is a stylised console.
<source lang=apl inline>⎕</source> is the prefix for all [[system name]]s, and also also manages input from the console as well as output to the console. For that, it is a stylised console.

Revision as of 20:23, 18 October 2020

Mnemonics can assist with remembering the meaning of APL glyphs where on they keyboard they are found for typing them. Both of these skills are essential for an effective APL programmer. This article currently provides examples such aide-mémoires, but will be completed in due time.

Pairing glyphs with their meaning

(Diamond) separates statements. That is, no functions or operators can break through , just as diamonds are virtually indestructible.

looks like a -shaped Stencil laid on a piece of paper, .

@ applies a function or substitutes elements at specific locations.

(I-beam) calls system services. APL was originally developed at IBM, so system services were also IBM services. is an I-beam and I-beam is pronounced almost identically to IBM.

and give the indices (grades) needed to sort ascending and descending respectively, and look like an ascending and descending supersonic transport, respectively.

, , and reverse or transpose an array over a given axis. The part of the glyphs symbolise the array, while the line component (|, \, or -) indicates the line across which the reversal/transposal is done.

looks like the cross-section of a tree log

and have the Not glyph ~ on top of or overlaid on the Or glyph and And glyph respectively.

is matrix divide with a symbolising a matrix and an inscribed ÷ for "divide".

? symbolises the unknown, and thus rolls dice and deals cards randomly.

and are the leftmost and rightmost letters of the Greek alphabet.

is the Greek letter Epsilon which corresponds to the letter **E** for Enlist and Element of.

is the Greek letter Rho which corresponds to the letter **R** for Reshape.

is Not when monadic, but its dyadic form, Without can also be remembered as but not.

is the right-most letter of the Greek alphabet.

is the prefix for all system names, and also also manages input from the console as well as output to the console. For that, it is a stylised console.

/ and are also called "by" which can be remembered as reduce by.

Pairing glyphs/functionality with their keyboard locations

Below is a US English APL keyboard layout (from Dyalog APL), annotated with short mnemonics. Some of the mnemonics are then fully explained.

Keyboard Mnemonics.png

begins new APL expressions just like ` button begins the main section of the keyboard.
is a modified version of , so it is Shift+.

¨ applies a function to each 1 of the argument elements, so it is on APL+1.
looks like a Roman numeral 1, so it also lives on the 1.

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APL glyphs [edit]
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