greghendershott/rackjure — pull request #30 by qerub (2014-02-09 21:13:46+00:00)
Title: Implement ~> and ~>> (resolves #27)

Here we go.

It ended up really nice:

```racket
(define-syntax some~>>
(threading-syntax-parser
(lambda (form nested-form)
#`(if-let [tmp #,nested-form] (~>> tmp #,form) #f))))
```