Rails - Nov 2006 - Minor discrepancies running Thomas' "Roman" program: why?

Hi,

I''m running Ruby 1.8.2 over WinXP-Pro/SP2.

I''ve written a variant of Dave Thomas'' Decimal-to-Roman
program from
PickAxe 2.  I get a couple of minor differences in execution..

One difference is that my assert statements that test values need a
"to_s" to avoid failure.  His do not, e.g.

		assert_equal(''i'', Roman.new(1).to_s)
		assert_equal(''ii'', Roman.new(2).to_s)
		assert_equal(''iv'', Roman.new(4).to_s)

My statement
		assert_raise(RuntimeError, Roman.new(0))
shows up in the "errors" count and a traceback is produced. 
Dave''s
example shows no errors nor a traceback.

I test under SciTE and in a Command Window; they yield identical
results.

Dave''s book says he''s covering the same Ruby version
I''m using.  Could
it be he''s developing on Uni* while I''m on Windows?  The
code''s below
if your interested.

Thanks in Advance,
Richard

TestC.rb
=====equire ''roman3''  # No debugging code ... just one puts
statement
require ''test/unit''
class TestRoman < Test::Unit::TestCase
	def test_simple
		assert_equal(''i'', Roman.new(1).to_s)
		assert_equal(''ii'', Roman.new(2).to_s)
		assert_equal(''iv'', Roman.new(4).to_s)
		assert_equal(''v'', Roman.new(5).to_s)
		assert_equal(''vi'', Roman.new(6).to_s)
		assert_equal(''ixx'', Roman.new(19).to_s)
		assert_equal(''ic'', Roman.new(99).to_s)
		assert_equal(''ci'', Roman.new(101).to_s)
		assert_equal(''vmmmmm'', Roman.new(4995).to_s)
		assert_equal(''immmmm'', Roman.new(4999).to_s)
		assert_raise(RuntimeError, Roman.new(0))
	end
end

Results
====Loaded suite TestC
Started
1=>i
2=>ii
4=>iv
5=>v
6=>vi
19=>ixx
99=>ic
101=>ci
4995=>vmmmmm
4999=>immmmm
E
Finished in 0.0 seconds.

  1) Error:
test_simple(TestRoman):
RuntimeError: Roman numerals must be between 1 & 4999
    ./roman3.rb:9:in `initialize''
    TestC.rb:15:in `new''
    TestC.rb:15:in `test_simple''

1 tests, 10 assertions, 0 failures, 1 errors


Roman3.rb
=======class Roman
	MAXROMAN = 4999
	Symbols= [	["m", 1000], ["d", 500], ["c", 100],  
["l", 50],
				["x", 10],    ["v", 5],    ["i", 1]
			]

	def initialize(value)
		if value <= 0 || value > MAXROMAN
			fail "Roman numerals must be between 1 & #{MAXROMAN}"
		end
		@value = value
	end

	def to_s
		value = @value
		roman = ""
		# Check for exact match
		for code, dec_equiv in Symbols
			if dec_equiv == value then roman << code; value = 0;  break;  end
		end

		for code, dec_equiv in Symbols
			break unless value > 0
			orig_val =value
			count, value = value.divmod(dec_equiv)

			if (count < 0 || count * dec_equiv == orig_val)
			else
					for new_code, new_dec_equiv in Symbols
						next unless new_dec_equiv < dec_equiv
						if orig_val + new_dec_equiv == dec_equiv * (count+1)
							roman << new_code
							count += 1
							value = orig_val + new_dec_equiv - (count * dec_equiv)
							break
						end
					end
			end
			roman << (code * count)
			break if value == 0
		end
		puts @value.to_s + ''=>'' + roman
		roman
	end
end


--~--~---------~--~----~------------~-------~--~----~
 You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---

<...>
> My statement
>                 assert_raise(RuntimeError, Roman.new(0))
> shows up in the "errors" count and a traceback is produced. 
Dave''s
> example shows no errors nor a traceback.
<...>
> Dave''s book says he''s covering the same Ruby version
I''m using.  Could
> it be he''s developing on Uni* while I''m on Windows?
<...>

It has nothing to do with Uni* or Windows.

Your code:
 assert_raise(RuntimeError, Roman.new(0))
Dave''s code:
assert_raise(RuntimeError) { Roman.new(0) }

From the documentation of assert_raise:
  assert_raise(*args) {|| ...}
  Passes if the block raises one of the given exceptions.

Your code has no block...

--
Regards,
Rimantas
--
http://rimantas.com/

--~--~---------~--~----~------------~-------~--~----~
 You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---