NS Form Helper Class

form_helper.rb

class FormHelper
    attr_accessor :form
    
    def initialize(nsform=nil)
        @form = nsform
    end
    
    def length
        form.numberOfRows
    end
    
    def to_hash
        (0...self.length).inject({}) {|m,o|
            o = self.form.cellAtIndex(o)
            m[o.title] = o.stringValue
            m
        }
    end
    
    def to_a
        (0...self.length).map {|x| self.form.cellAtIndex(x) } 
    end
    
    def sum
        (0...self.length).inject(0) {|m,o|
            o = self.form.cellAtIndex(o)
            m + o.intValue
        }
    end
    
    def values
        self.to_hash.values
    end
    
    def [](key)
        if key.is_a?(String)
            self.to_hash[key]
        elsif key.is_a?(Integer)
            self.to_a[key]
        end
    end
end

intro.md

With MacRuby, you can easily extend or wrap any Cocoa class. The class below, FormHelper, gives a more ruby like interface to the NSForm, a fairly useful control in AppKit. All of a sudden

form.cellAtIndex(1).objectValue

becomes

form_helper["Email Address"]

So much boilerplate and standard code you'd write in Cocoa can be abstracted to neat helper classes with ruby's classy meta-programming.