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[[File:APL-keybd2.svg|thumb]]An '''overstrike''' refers to the practice of [[typing glyphs]] on top of each other to form a more complex [[glyph]]. This was the normal way of typing many APL characters in the early typewriter terminal days of APL. Only a single shift state was available (which would switch from numbers and uppercase letters to APL glyphs), so for example <source lang=apl inline>⍟</source> which is today typed using <kbd>APL</kbd>+<kbd>Shift</kbd>+<kbd>8</kbd> would instead be typed using <kbd>APL</kbd>+<kbd>O</kbd> for <source lang=apl inline>○</source> followed by <kbd>⟵ Backspace</kbd> and then  <kbd>APL</kbd>+<kbd>P</kbd> for <source lang=apl inline>*</source>.
[[File:APL-keybd2.svg|thumb]]An '''overstrike''' refers to the practice of [[typing glyphs]] on top of each other to form a more complex [[glyph]]. This was the normal way of typing many APL characters in the early typewriter terminal days of APL. Only a single shift state was available (which would switch from numbers and uppercase letters to APL glyphs), so for example <syntaxhighlight lang=apl inline>⍟</syntaxhighlight> which is today typed using <kbd>APL</kbd>+<kbd>Shift</kbd>+<kbd>8</kbd> would instead be typed using <kbd>APL</kbd>+<kbd>O</kbd> for <syntaxhighlight lang=apl inline>○</syntaxhighlight> followed by <kbd>⟵ Backspace</kbd> and then  <kbd>APL</kbd>+<kbd>P</kbd> for <syntaxhighlight lang=apl inline>*</syntaxhighlight>.


== Support ==
== Support ==
Support for various overstrikes vary.
Support for various overstrikes vary.
=== APL\360 ===
=== APL\360 ===
[[APL\360]] supported many overstrikes, and these were the only way to type composite glyphs. Since typewriters couldn't remove typed characters, editing could be cumbersome, and so some innovative overstrikes were allowed for the odd case where one was correcting a typographical error. For example, <source lang=apl inline>F</source> and <source lang=apl inline>L</source> would form <source lang=apl inline>E</source>.
[[APL\360]] supported many overstrikes, and these were the only way to type composite glyphs. Since typewriters couldn't remove typed characters, editing could be cumbersome, and so some innovative overstrikes were allowed for the odd case where one was correcting a typographical error. For example, <syntaxhighlight lang=apl inline>F</syntaxhighlight> and <syntaxhighlight lang=apl inline>L</syntaxhighlight> would form <syntaxhighlight lang=apl inline>E</syntaxhighlight>.
=== Dyalog APL ===
=== Dyalog APL ===
<div class="toccolours mw-collapsible mw-collapsed" style="background:none">[[Dyalog APL]] supports the following overstrikes in any order of input:<div class="mw-collapsible-content">
<div class="toccolours mw-collapsible mw-collapsed" style="background:none">[[Dyalog APL]] supports the following overstrikes in any order of input:<div class="mw-collapsible-content">
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! First !! Second !! Result
! First !! Second !! Result
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|<source lang=apl inline>'</source>||<source lang=apl inline>.</source>||<source lang=apl inline>!</source>
|<syntaxhighlight lang=apl inline>'</syntaxhighlight>||<syntaxhighlight lang=apl inline>.</syntaxhighlight>||<syntaxhighlight lang=apl inline>!</syntaxhighlight>
|-
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|<source lang=apl inline>'</source>||<source lang=apl inline>⎕</source>||<source lang=apl inline>⍞</source>
|<syntaxhighlight lang=apl inline>'</syntaxhighlight>||<syntaxhighlight lang=apl inline>⎕</syntaxhighlight>||<syntaxhighlight lang=apl inline>⍞</syntaxhighlight>
|-
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|<source lang=apl inline>(</source>||<source lang=apl inline>-</source>||<source lang=apl inline>⊢</source>
|<syntaxhighlight lang=apl inline>(</syntaxhighlight>||<syntaxhighlight lang=apl inline>-</syntaxhighlight>||<syntaxhighlight lang=apl inline>⊢</syntaxhighlight>
|-
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|<source lang=apl inline>)</source>||<source lang=apl inline>-</source>||<source lang=apl inline>⊣</source>
|<syntaxhighlight lang=apl inline>)</syntaxhighlight>||<syntaxhighlight lang=apl inline>-</syntaxhighlight>||<syntaxhighlight lang=apl inline>⊣</syntaxhighlight>
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|<source lang=apl inline>*</source>||<source lang=apl inline>¨</source>||<source lang=apl inline>⍣</source>
|<syntaxhighlight lang=apl inline>*</syntaxhighlight>||<syntaxhighlight lang=apl inline>¨</syntaxhighlight>||<syntaxhighlight lang=apl inline>⍣</syntaxhighlight>
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|<source lang=apl inline>*</source>||<source lang=apl inline>○</source>||<source lang=apl inline>⍟</source>
|<syntaxhighlight lang=apl inline>*</syntaxhighlight>||<syntaxhighlight lang=apl inline>○</syntaxhighlight>||<syntaxhighlight lang=apl inline>⍟</syntaxhighlight>
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|<source lang=apl inline>,</source>||<source lang=apl inline>-</source>||<source lang=apl inline>⍪</source>
|<syntaxhighlight lang=apl inline>,</syntaxhighlight>||<syntaxhighlight lang=apl inline>-</syntaxhighlight>||<syntaxhighlight lang=apl inline>⍪</syntaxhighlight>
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|-
|<source lang=apl inline>-</source>||<source lang=apl inline>/</source>||<source lang=apl inline>⌿</source>
|<syntaxhighlight lang=apl inline>-</syntaxhighlight>||<syntaxhighlight lang=apl inline>/</syntaxhighlight>||<syntaxhighlight lang=apl inline>⌿</syntaxhighlight>
|-
|-
|<source lang=apl inline>-</source>||<source lang=apl inline>E</source>||<source lang=apl inline>€</source>
|<syntaxhighlight lang=apl inline>-</syntaxhighlight>||<syntaxhighlight lang=apl inline>E</syntaxhighlight>||<syntaxhighlight lang=apl inline>€</syntaxhighlight>
|-
|-
|<source lang=apl inline>-</source>||<source lang=apl inline>L</source>||<source lang=apl inline>£</source>
|<syntaxhighlight lang=apl inline>-</syntaxhighlight>||<syntaxhighlight lang=apl inline>L</syntaxhighlight>||<syntaxhighlight lang=apl inline>£</syntaxhighlight>
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|-
|<source lang=apl inline>-</source>||<source lang=apl inline>\</source>||<source lang=apl inline>⍀</source>
|<syntaxhighlight lang=apl inline>-</syntaxhighlight>||<syntaxhighlight lang=apl inline>\</syntaxhighlight>||<syntaxhighlight lang=apl inline>⍀</syntaxhighlight>
|-
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|<source lang=apl inline>-</source>||<source lang=apl inline>|</source>||<source lang=apl inline>ɫ</source>
|<syntaxhighlight lang=apl inline>-</syntaxhighlight>||<syntaxhighlight lang=apl inline>|</syntaxhighlight>||<syntaxhighlight lang=apl inline>ɫ</syntaxhighlight>
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|-
|<source lang=apl inline>-</source>||<source lang=apl inline>○</source>||<source lang=apl inline>⊖</source>
|<syntaxhighlight lang=apl inline>-</syntaxhighlight>||<syntaxhighlight lang=apl inline>○</syntaxhighlight>||<syntaxhighlight lang=apl inline>⊖</syntaxhighlight>
|-
|-
|<source lang=apl inline>0</source>||<source lang=apl inline>~</source>||<source lang=apl inline>⍬</source>
|<syntaxhighlight lang=apl inline>0</syntaxhighlight>||<syntaxhighlight lang=apl inline>~</syntaxhighlight>||<syntaxhighlight lang=apl inline>⍬</syntaxhighlight>
|-
|-
|<source lang=apl inline>:</source>||<source lang=apl inline>⎕</source>||<source lang=apl inline>⍠</source>
|<syntaxhighlight lang=apl inline>:</syntaxhighlight>||<syntaxhighlight lang=apl inline>⎕</syntaxhighlight>||<syntaxhighlight lang=apl inline>⍠</syntaxhighlight>
|-
|-
|<source lang=apl inline><</source>||<source lang=apl inline>></source>||<source lang=apl inline>⋄</source>
|<syntaxhighlight lang=apl inline><</syntaxhighlight>||<syntaxhighlight lang=apl inline>></syntaxhighlight>||<syntaxhighlight lang=apl inline>⋄</syntaxhighlight>
|-
|-
|<source lang=apl inline>=</source>||<source lang=apl inline>_</source>||<source lang=apl inline>≡</source>
|<syntaxhighlight lang=apl inline>=</syntaxhighlight>||<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>≡</syntaxhighlight>
|-
|-
|<source lang=apl inline>=</source>||<source lang=apl inline>⎕</source>||<source lang=apl inline>⌸</source>
|<syntaxhighlight lang=apl inline>=</syntaxhighlight>||<syntaxhighlight lang=apl inline>⎕</syntaxhighlight>||<syntaxhighlight lang=apl inline>⌸</syntaxhighlight>
|-
|-
|<source lang=apl inline>A</source>||<source lang=apl inline>_</source>||<source lang=apl inline>Ⓐ</source>
|<syntaxhighlight lang=apl inline>A</syntaxhighlight>||<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>Ⓐ</syntaxhighlight>
|-
|-
|<source lang=apl inline>B</source>||<source lang=apl inline>_</source>||<source lang=apl inline>Ⓑ</source>
|<syntaxhighlight lang=apl inline>B</syntaxhighlight>||<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>Ⓑ</syntaxhighlight>
|-
|-
|<source lang=apl inline>C</source>||<source lang=apl inline>_</source>||<source lang=apl inline>Ⓒ</source>
|<syntaxhighlight lang=apl inline>C</syntaxhighlight>||<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>Ⓒ</syntaxhighlight>
|-
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|<source lang=apl inline>D</source>||<source lang=apl inline>_</source>||<source lang=apl inline>Ⓓ</source>
|<syntaxhighlight lang=apl inline>D</syntaxhighlight>||<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>Ⓓ</syntaxhighlight>
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|<source lang=apl inline>E</source>||<source lang=apl inline>_</source>||<source lang=apl inline>Ⓔ</source>
|<syntaxhighlight lang=apl inline>E</syntaxhighlight>||<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>Ⓔ</syntaxhighlight>
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|<source lang=apl inline>F</source>||<source lang=apl inline>_</source>||<source lang=apl inline>Ⓕ</source>
|<syntaxhighlight lang=apl inline>F</syntaxhighlight>||<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>Ⓕ</syntaxhighlight>
|-
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|<source lang=apl inline>G</source>||<source lang=apl inline>_</source>||<source lang=apl inline>Ⓖ</source>
|<syntaxhighlight lang=apl inline>G</syntaxhighlight>||<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>Ⓖ</syntaxhighlight>
|-
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|<source lang=apl inline>H</source>||<source lang=apl inline>_</source>||<source lang=apl inline>Ⓗ</source>
|<syntaxhighlight lang=apl inline>H</syntaxhighlight>||<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>Ⓗ</syntaxhighlight>
|-
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|<source lang=apl inline>I</source>||<source lang=apl inline>_</source>||<source lang=apl inline>Ⓘ</source>
|<syntaxhighlight lang=apl inline>I</syntaxhighlight>||<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>Ⓘ</syntaxhighlight>
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|<source lang=apl inline>J</source>||<source lang=apl inline>_</source>||<source lang=apl inline>Ⓙ</source>
|<syntaxhighlight lang=apl inline>J</syntaxhighlight>||<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>Ⓙ</syntaxhighlight>
|-
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|<source lang=apl inline>K</source>||<source lang=apl inline>_</source>||<source lang=apl inline>Ⓚ</source>
|<syntaxhighlight lang=apl inline>K</syntaxhighlight>||<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>Ⓚ</syntaxhighlight>
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|<source lang=apl inline>L</source>||<source lang=apl inline>_</source>||<source lang=apl inline>Ⓛ</source>
|<syntaxhighlight lang=apl inline>L</syntaxhighlight>||<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>Ⓛ</syntaxhighlight>
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|<source lang=apl inline>M</source>||<source lang=apl inline>_</source>||<source lang=apl inline>Ⓜ</source>
|<syntaxhighlight lang=apl inline>M</syntaxhighlight>||<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>Ⓜ</syntaxhighlight>
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|<source lang=apl inline>N</source>||<source lang=apl inline>_</source>||<source lang=apl inline>Ⓝ</source>
|<syntaxhighlight lang=apl inline>N</syntaxhighlight>||<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>Ⓝ</syntaxhighlight>
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|<source lang=apl inline>O</source>||<source lang=apl inline>_</source>||<source lang=apl inline>Ⓞ</source>
|<syntaxhighlight lang=apl inline>O</syntaxhighlight>||<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>Ⓞ</syntaxhighlight>
|-
|-
|<source lang=apl inline>P</source>||<source lang=apl inline>_</source>||<source lang=apl inline>Ⓟ</source>
|<syntaxhighlight lang=apl inline>P</syntaxhighlight>||<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>Ⓟ</syntaxhighlight>
|-
|-
|<source lang=apl inline>Q</source>||<source lang=apl inline>_</source>||<source lang=apl inline>Ⓠ</source>
|<syntaxhighlight lang=apl inline>Q</syntaxhighlight>||<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>Ⓠ</syntaxhighlight>
|-
|-
|<source lang=apl inline>R</source>||<source lang=apl inline>_</source>||<source lang=apl inline>Ⓡ</source>
|<syntaxhighlight lang=apl inline>R</syntaxhighlight>||<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>Ⓡ</syntaxhighlight>
|-
|-
|<source lang=apl inline>S</source>||<source lang=apl inline>_</source>||<source lang=apl inline>Ⓢ</source>
|<syntaxhighlight lang=apl inline>S</syntaxhighlight>||<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>Ⓢ</syntaxhighlight>
|-
|-
|<source lang=apl inline>S</source>||<source lang=apl inline>|</source>||<source lang=apl inline>$</source>
|<syntaxhighlight lang=apl inline>S</syntaxhighlight>||<syntaxhighlight lang=apl inline>|</syntaxhighlight>||<syntaxhighlight lang=apl inline>$</syntaxhighlight>
|-
|-
|<source lang=apl inline>T</source>||<source lang=apl inline>_</source>||<source lang=apl inline>Ⓣ</source>
|<syntaxhighlight lang=apl inline>T</syntaxhighlight>||<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>Ⓣ</syntaxhighlight>
|-
|-
|<source lang=apl inline>U</source>||<source lang=apl inline>_</source>||<source lang=apl inline>Ⓤ</source>
|<syntaxhighlight lang=apl inline>U</syntaxhighlight>||<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>Ⓤ</syntaxhighlight>
|-
|-
|<source lang=apl inline>V</source>||<source lang=apl inline>_</source>||<source lang=apl inline>Ⓥ</source>
|<syntaxhighlight lang=apl inline>V</syntaxhighlight>||<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>Ⓥ</syntaxhighlight>
|-
|-
|<source lang=apl inline>W</source>||<source lang=apl inline>_</source>||<source lang=apl inline>Ⓦ</source>
|<syntaxhighlight lang=apl inline>W</syntaxhighlight>||<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>Ⓦ</syntaxhighlight>
|-
|-
|<source lang=apl inline>X</source>||<source lang=apl inline>_</source>||<source lang=apl inline>Ⓧ</source>
|<syntaxhighlight lang=apl inline>X</syntaxhighlight>||<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>Ⓧ</syntaxhighlight>
|-
|-
|<source lang=apl inline>Y</source>||<source lang=apl inline>_</source>||<source lang=apl inline>Ⓨ</source>
|<syntaxhighlight lang=apl inline>Y</syntaxhighlight>||<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>Ⓨ</syntaxhighlight>
|-
|-
|<source lang=apl inline>Z</source>||<source lang=apl inline>_</source>||<source lang=apl inline>Ⓩ</source>
|<syntaxhighlight lang=apl inline>Z</syntaxhighlight>||<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>Ⓩ</syntaxhighlight>
|-
|-
|<source lang=apl inline>[</source>||<source lang=apl inline>]</source>||<source lang=apl inline>⌷</source>
|<syntaxhighlight lang=apl inline>[</syntaxhighlight>||<syntaxhighlight lang=apl inline>]</syntaxhighlight>||<syntaxhighlight lang=apl inline>⌷</syntaxhighlight>
|-
|-
|<source lang=apl inline>[</source>||<source lang=apl inline>∘</source>||<source lang=apl inline>{</source>
|<syntaxhighlight lang=apl inline>[</syntaxhighlight>||<syntaxhighlight lang=apl inline>∘</syntaxhighlight>||<syntaxhighlight lang=apl inline>{</syntaxhighlight>
|-
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|<source lang=apl inline>\</source>||<source lang=apl inline>○</source>||<source lang=apl inline>⍉</source>
|<syntaxhighlight lang=apl inline>\</syntaxhighlight>||<syntaxhighlight lang=apl inline>○</syntaxhighlight>||<syntaxhighlight lang=apl inline>⍉</syntaxhighlight>
|-
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|<source lang=apl inline>]</source>||<source lang=apl inline>∘</source>||<source lang=apl inline>}</source>
|<syntaxhighlight lang=apl inline>]</syntaxhighlight>||<syntaxhighlight lang=apl inline>∘</syntaxhighlight>||<syntaxhighlight lang=apl inline>}</syntaxhighlight>
|-
|-
|<source lang=apl inline>_</source>||<source lang=apl inline>∆</source>||<source lang=apl inline>⍙</source>
|<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>∆</syntaxhighlight>||<syntaxhighlight lang=apl inline>⍙</syntaxhighlight>
|-
|-
|<source lang=apl inline>_</source>||<source lang=apl inline>∊</source>||<source lang=apl inline>⍷</source>
|<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>∊</syntaxhighlight>||<syntaxhighlight lang=apl inline>⍷</syntaxhighlight>
|-
|-
|<source lang=apl inline>_</source>||<source lang=apl inline>≠</source>||<source lang=apl inline>≢</source>
|<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>≠</syntaxhighlight>||<syntaxhighlight lang=apl inline>≢</syntaxhighlight>
|-
|-
|<source lang=apl inline>_</source>||<source lang=apl inline>⊂</source>||<source lang=apl inline>⊆</source>
|<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>⊂</syntaxhighlight>||<syntaxhighlight lang=apl inline>⊆</syntaxhighlight>
|-
|-
|<source lang=apl inline>_</source>||<source lang=apl inline>⍳</source>||<source lang=apl inline>⍸</source>
|<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>⍳</syntaxhighlight>||<syntaxhighlight lang=apl inline>⍸</syntaxhighlight>
|-
|-
|<source lang=apl inline>_</source>||<source lang=apl inline>⍵</source>||<source lang=apl inline>⍹</source>
|<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>⍵</syntaxhighlight>||<syntaxhighlight lang=apl inline>⍹</syntaxhighlight>
|-
|-
|<source lang=apl inline>_</source>||<source lang=apl inline>⍺</source>||<source lang=apl inline>⍶</source>
|<syntaxhighlight lang=apl inline>_</syntaxhighlight>||<syntaxhighlight lang=apl inline>⍺</syntaxhighlight>||<syntaxhighlight lang=apl inline>⍶</syntaxhighlight>
|-
|-
|<source lang=apl inline>|</source>||<source lang=apl inline>∆</source>||<source lang=apl inline>⍋</source>
|<syntaxhighlight lang=apl inline>|</syntaxhighlight>||<syntaxhighlight lang=apl inline>∆</syntaxhighlight>||<syntaxhighlight lang=apl inline>⍋</syntaxhighlight>
|-
|-
|<source lang=apl inline>|</source>||<source lang=apl inline>∇</source>||<source lang=apl inline>⍒</source>
|<syntaxhighlight lang=apl inline>|</syntaxhighlight>||<syntaxhighlight lang=apl inline>∇</syntaxhighlight>||<syntaxhighlight lang=apl inline>⍒</syntaxhighlight>
|-
|-
|<source lang=apl inline>|</source>||<source lang=apl inline>⊂</source>||<source lang=apl inline>¢</source>
|<syntaxhighlight lang=apl inline>|</syntaxhighlight>||<syntaxhighlight lang=apl inline>⊂</syntaxhighlight>||<syntaxhighlight lang=apl inline>¢</syntaxhighlight>
|-
|-
|<source lang=apl inline>|</source>||<source lang=apl inline>○</source>||<source lang=apl inline>⌽</source>
|<syntaxhighlight lang=apl inline>|</syntaxhighlight>||<syntaxhighlight lang=apl inline>○</syntaxhighlight>||<syntaxhighlight lang=apl inline>⌽</syntaxhighlight>
|-
|-
|<source lang=apl inline>~</source>||<source lang=apl inline>¨</source>||<source lang=apl inline>⍨</source>
|<syntaxhighlight lang=apl inline>~</syntaxhighlight>||<syntaxhighlight lang=apl inline>¨</syntaxhighlight>||<syntaxhighlight lang=apl inline>⍨</syntaxhighlight>
|-
|-
|<source lang=apl inline>~</source>||<source lang=apl inline>∇</source>||<source lang=apl inline>⍫</source>
|<syntaxhighlight lang=apl inline>~</syntaxhighlight>||<syntaxhighlight lang=apl inline>∇</syntaxhighlight>||<syntaxhighlight lang=apl inline>⍫</syntaxhighlight>
|-
|-
|<source lang=apl inline>~</source>||<source lang=apl inline>∧</source>||<source lang=apl inline>⍲</source>
|<syntaxhighlight lang=apl inline>~</syntaxhighlight>||<syntaxhighlight lang=apl inline>∧</syntaxhighlight>||<syntaxhighlight lang=apl inline>⍲</syntaxhighlight>
|-
|-
|<source lang=apl inline>~</source>||<source lang=apl inline>∨</source>||<source lang=apl inline>⍱</source>
|<syntaxhighlight lang=apl inline>~</syntaxhighlight>||<syntaxhighlight lang=apl inline>∨</syntaxhighlight>||<syntaxhighlight lang=apl inline>⍱</syntaxhighlight>
|-
|-
|<source lang=apl inline>¨</source>||<source lang=apl inline>∇</source>||<source lang=apl inline>⍢</source>
|<syntaxhighlight lang=apl inline>¨</syntaxhighlight>||<syntaxhighlight lang=apl inline>∇</syntaxhighlight>||<syntaxhighlight lang=apl inline>⍢</syntaxhighlight>
|-
|-
|<source lang=apl inline>¨</source>||<source lang=apl inline>∘</source>||<source lang=apl inline>⍤</source>
|<syntaxhighlight lang=apl inline>¨</syntaxhighlight>||<syntaxhighlight lang=apl inline>∘</syntaxhighlight>||<syntaxhighlight lang=apl inline>⍤</syntaxhighlight>
|-
|-
|<source lang=apl inline>¨</source>||<source lang=apl inline>○</source>||<source lang=apl inline>⍥</source>
|<syntaxhighlight lang=apl inline>¨</syntaxhighlight>||<syntaxhighlight lang=apl inline>○</syntaxhighlight>||<syntaxhighlight lang=apl inline>⍥</syntaxhighlight>
|-
|-
|<source lang=apl inline>÷</source>||<source lang=apl inline>⎕</source>||<source lang=apl inline>⌹</source>
|<syntaxhighlight lang=apl inline>÷</syntaxhighlight>||<syntaxhighlight lang=apl inline>⎕</syntaxhighlight>||<syntaxhighlight lang=apl inline>⌹</syntaxhighlight>
|-
|-
|<source lang=apl inline>∘</source>||<source lang=apl inline>∩</source>||<source lang=apl inline>⍝</source>
|<syntaxhighlight lang=apl inline>∘</syntaxhighlight>||<syntaxhighlight lang=apl inline>∩</syntaxhighlight>||<syntaxhighlight lang=apl inline>⍝</syntaxhighlight>
|-
|-
|<source lang=apl inline>∘</source>||<source lang=apl inline>⊤</source>||<source lang=apl inline>⍕</source>
|<syntaxhighlight lang=apl inline>∘</syntaxhighlight>||<syntaxhighlight lang=apl inline>⊤</syntaxhighlight>||<syntaxhighlight lang=apl inline>⍕</syntaxhighlight>
|-
|-
|<source lang=apl inline>∘</source>||<source lang=apl inline>⊥</source>||<source lang=apl inline>⍎</source>
|<syntaxhighlight lang=apl inline>∘</syntaxhighlight>||<syntaxhighlight lang=apl inline>⊥</syntaxhighlight>||<syntaxhighlight lang=apl inline>⍎</syntaxhighlight>
|-
|-
|<source lang=apl inline>∧</source>||<source lang=apl inline>∨</source>||<source lang=apl inline>⋄</source>
|<syntaxhighlight lang=apl inline>∧</syntaxhighlight>||<syntaxhighlight lang=apl inline>∨</syntaxhighlight>||<syntaxhighlight lang=apl inline>⋄</syntaxhighlight>
|-
|-
|<source lang=apl inline>⊤</source>||<source lang=apl inline>⊥</source>||<source lang=apl inline>⌶</source>
|<syntaxhighlight lang=apl inline>⊤</syntaxhighlight>||<syntaxhighlight lang=apl inline>⊥</syntaxhighlight>||<syntaxhighlight lang=apl inline>⌶</syntaxhighlight>
|-
|-
|<source lang=apl inline>⋄</source>||<source lang=apl inline>⎕</source>||<source lang=apl inline>⌺</source>
|<syntaxhighlight lang=apl inline>⋄</syntaxhighlight>||<syntaxhighlight lang=apl inline>⎕</syntaxhighlight>||<syntaxhighlight lang=apl inline>⌺</syntaxhighlight>
|-
|-
|}
|}

Latest revision as of 22:10, 10 September 2022

APL-keybd2.svg

An overstrike refers to the practice of typing glyphs on top of each other to form a more complex glyph. This was the normal way of typing many APL characters in the early typewriter terminal days of APL. Only a single shift state was available (which would switch from numbers and uppercase letters to APL glyphs), so for example ⍟ which is today typed using APL+Shift+8 would instead be typed using APL+O for ○ followed by ⟵ Backspace and then APL+P for *.

Support

Support for various overstrikes vary.

APL\360

APL\360 supported many overstrikes, and these were the only way to type composite glyphs. Since typewriters couldn't remove typed characters, editing could be cumbersome, and so some innovative overstrikes were allowed for the odd case where one was correcting a typographical error. For example, F and L would form E.

Dyalog APL

Dyalog APL supports the following overstrikes in any order of input:
First Second Result
' . !
' ⎕ ⍞
( - ⊢
) - ⊣
* ¨ ⍣
* ○ ⍟
, - ⍪
- / ⌿
- E €
- L £
- \ ⍀
- | ɫ
- ○ ⊖
0 ~ ⍬
: ⎕ ⍠
< > ⋄
= _ ≡
= ⎕ ⌸
A _ Ⓐ
B _ Ⓑ
C _ Ⓒ
D _ Ⓓ
E _ Ⓔ
F _ Ⓕ
G _ Ⓖ
H _ Ⓗ
I _ Ⓘ
J _ Ⓙ
K _ Ⓚ
L _ Ⓛ
M _ Ⓜ
N _ Ⓝ
O _ Ⓞ
P _ Ⓟ
Q _ Ⓠ
R _ Ⓡ
S _ Ⓢ
S | $
T _ Ⓣ
U _ Ⓤ
V _ Ⓥ
W _ Ⓦ
X _ Ⓧ
Y _ Ⓨ
Z _ Ⓩ
[ ] ⌷
[ ∘ {
\ ○ ⍉
] ∘ }
_ ∆ ⍙
_ ∊ ⍷
_ ≠ ≢
_ ⊂ ⊆
_ ⍳ ⍸
_ ⍵ ⍹
_ ⍺ ⍶
| ∆ ⍋
| ∇ ⍒
| ⊂ ¢
| ○ ⌽
~ ¨ ⍨
~ ∇ ⍫
~ ∧ ⍲
~ ∨ ⍱
¨ ∇ ⍢
¨ ∘ ⍤
¨ ○ ⍥
÷ ⎕ ⌹
∘ ∩ ⍝
∘ ⊤ ⍕
∘ ⊥ ⍎
∧ ∨ ⋄
⊤ ⊥ ⌶
⋄ ⎕ ⌺
APL glyphs [edit]
Information Glyph ∙ Typing glyphs (on Linux) ∙ Unicode ∙ Fonts ∙ Mnemonics ∙ Overstrikes ∙ Migration level
Individual glyphs Jot (∘) ∙ Right Shoe (⊃) ∙ Up Arrow (↑) ∙ Zilde (⍬) ∙ High minus (¯) ∙ Dot (.) ∙ Del (∇)
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