Installing Homebrew in previous OS X versions was holding a dependency on having Xcode pre-installed which is a substantial dependency (in terms of volume size) especially considering that you might not even be using this IDE as was always my case.
Not any more.
Apparently the Xcode part that is needed by Homebrew and other 3rd party tools, dubbed Command Line Tool in the net, has been extracted from Xcode and is being made available via the simple Terminal command in Mac OS X 10.9:
that pops up a pane to confirm auto-download of the tool.
From that point onwards Homebrew installation can continue with the ruby script as it was always the case. After installation completes ‘brew doctor’ can assure you that all is good and you can start amassing Cellars for the brewing process.