require 'formula' class PostgresqlInstalled < Requirement def message; <<-EOS.undent PostgresQL is required to install. You can install this with: brew install postgresql Or you can use an official installer from: http://www.postgresql.org/ EOS end def satisfied? which 'postgres' end def fatal? true end end class Skytools < Formula homepage 'http://pgfoundry.org/projects/skytools/' url 'http://pgfoundry.org/frs/download.php/3321/skytools-3.1.tar.gz' sha1 'f31fb7096f160fb959f8a217cbea529da04b277e' depends_on PostgresqlInstalled.new def install system "./configure", "--prefix=#{prefix}" system "make" system "make install" end end