The new wart interpreter (http://arclanguage.org/item?id=14881) no longer reserves '|' for syms. It also lets you skip parens and use indent if you choose.
wart> assign f 3
wart> f
3
wart> assign f (lambda() 34)
wart> (f)
34
wart> def f()
35
; extra <enter> like python
wart> (f)
35
