# `⍺` — 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](../dfns.ipynb#arguments) gives the full rule.

``` bpl
10{⍺-⍵}3           ⍝ 7
```

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

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