Hi all,
In Ruby, I have a fairly complex nested object structure that I
serialize to a
yaml file. Then, in another program, I read it into a varaible like
this:
obj = YAML::load_file(“myfile.yaml”);
I can see all objects and names in obj within irb, but I can’t access
them
individually. For instance, in the original native that created the
yaml,
there’s this:
obj.customer.city
You cannot access that from the object read in with load_file. It
creates an
error condition.
What DOES work is:
obj = Purchase.new(nil, nil)
obj = YAML::load_file(“myfile.yaml”);
puts obj.customer.city
That prints “Apopka”.
A sample program is at the bottom of this email. As long as the classes
are
defined in the program, they can be accessed. But if an object is
created via
YAML::load_file(), I’m not able to access its data members.
Is there any way I can do it without including the class definition in
the
code?
Thanks
SteveT
Steve L.
Recession Relief Package
############ SAMPLE PROGRAM ###################
#!/usr/bin/ruby -w
require “yaml”
class Address
attr_accessor :street, :city, :state, :zip
def initialize(street, city, state, zip)
@street = street
@city = city
@state = state
@zip=zip
end
end
class Customer
attr_accessor :fname, :lname, :address
def initialize( fname, lname, address)
@fname = fname
@lname = lname
@address = address
end
end
class Item
attr_accessor :quantity, :priceper, :name
def initialize(name, quantity, priceper)
@name = name
@quantity = quantity
@priceper = priceper
end
end
class Purchase
attr_accessor :customer
attr_reader :amount
attr_accessor :date
attr_reader :items
def initialize(customer, date)
@customer = customer
@amount = amount
@date = date
@items = Array.new()
end
def additem(item)
@items.push(item)
end
def update_amount()
@amount = 0
@items.each do
|item|
@amount += (item.quantity.to_f * item.priceper.to_f)
end
end
end
MAIN ROUTINE
Load objects
address = Address.new([“121 Main Street”, “Suite
201”], “Apopka”, “FL”, “33333”);
customer = Customer.new(“Steve”, “Litt”, address)
purchase = Purchase.new(customer, “3/3/2033”)
purchase.additem(Item.new(“Widget”, 1, 1.00));
purchase.additem(Item.new(“Gadget”, 2, 2.00));
purchase.additem(Item.new(“Left handed smoke bender”, 3, 3.00));
purchase.update_amount()
Write out YAML to junk.yaml
ouf = File.new(“./junk.yaml”, “w”);
ouf.write(YAML::dump(purchase))
ouf.close()
WRITE REPORT
Read YAML file and load into Purchase object p
p=Purchase.new(nil, nil)
p=YAML::load_file(“./junk.yaml”);
Date and total
printf “Purchase on %s, total cost $%0.2f\n”, p.date, p.amount
Customer data
printf “\nCUSTOMER DATA:\n”
printf “%s %s\n”, p.customer.fname, p.customer.lname
p.customer.address.street.each {|i| puts i}
printf “%s, %s, %s\n”, p.customer.address.city,
p.customer.address.state,
p.customer.address.zip
Items
printf “\nITEMS PURCHASED\n”
printf “%30s %10s %10s %10s\n”, “ITEM NAME”, “QUANTITY”, “@”, “TOTAL”
p.items.each do
|item|
printf “%30s %10d %10.2f %10.2f\n”, item.name, item.quantity,
item.priceper,
item.quantity * item.priceper
end
printf “%30s %10s %10s %10s\n”, " ", " ", " ", “----------”
printf “%30s %10s %10s %10.2f\n”, “TOTAL”, " ", " ", p.amount
############ END OF SAMPLE PROGRAM ###################