Typically, in APLMON data no primitive stands out.
Utilities create targets suitable for later optimization.
For example:
ch←{0=⍬⍴⍴⍵:(⍴⍴⍵)↓1 ⋄ 1,2≢/⊂[1↓⍳⍴⍴⍵]⍵}
ch 'aacccbbbbbd'
1 0 1 0 0 1 0 0 0 0 1
ch 1 1 1 1 1
1 0 0 0 0
ch 12345
1
ch ,5
1
ch ''
⎕←x←↑3 2 1/'Morten' 'Roger' 'Serena'
Morten
Morten
Morten
Roger
Roger
Serena
ch x
1 0 0 1 0 1
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