!

This procedure allows either to edit and re-execute the last expression entered in interactive mode (entering (!) ) or a selected expression referenced by its number (entering e.g. (! 2) ).

The editor in the variable the-current-editor is invoked to edit the expression.

Example (invoking an external editor at [4]):

[1] (define a 1)
a
[2] (set! a (+ a 1))
a
[3] a
2
[4] (! 2)
ok
[5] a
3
[6]