This is a Ruby tree! It shows every object from the Ruby Programming Language in a tree format.

unscan 

        # StringScanner.unscan

(from ruby core)
---
    unscan()

---

Sets the scan pointer to the previous position.  Only one previous
position is remembered, and it changes with each scanning operation.

    s = StringScanner.new('test string')
    s.scan(/\w+/)        # => "test"
    s.unscan
    s.scan(/../)         # => "te"
    s.scan(/\d/)         # => nil
    s.unscan             # ScanError: unscan failed: previous match record not exist

This is MURDOC! A Ruby documentation browser inspired by Smalltalk-80. It allows you to learn about Ruby by browsing through its class hierarchies, and see any of its methods.