⍺ — Left argument

Argument. Keys: Alt-a

⍺ is the current dfn’s left argument. In a call with one argument, ⍺ is absent and drops out of the expression that uses it. For example, {⍺-⍵}3 is ¯3. Dfns gives the full rule.

10{⍺-⍵}3           ⍝ 7

⍺←expression supplies a lazy default, evaluated only on monadic calls.

{⍺←2 ⋄ ⍺×⍵}3       ⍝ 6
4{⍺←2 ⋄ ⍺×⍵}3      ⍝ 12