From: Gavin Kistner <gavin@...>
Date: 2004-10-27T21:39:39+09:00
Subject: Re: Learning erb

On Oct 26, 2004, at 10:06 PM, Bill Atkins wrote:
> I think what he's saying is that <%= "34" %> will output a 34 to the
> result, but <% puts 34 %> will output that stream to STDOUT.  So if he
> were calling ERb#result, he'd get the result of the former in its
> return value but the second statement's output wouldn't go into the
> result string.

Ah, you're right. I was confused because of the limited test case I was 
doing.

These two tests make clear that what you say is true:

Test 1:
	require 'erb'
	a = 99
	puts ERB.new( "<% print a %> bottles of beer. <% print a %> I say." 
).result( binding )
	#=> 9999 bottles of beer.  I say.

Test 2:
	require 'erb'
	a = 99
	ERB.new( "<% print a %> bottles of beer. <% print a %> I say." 
).result( binding )
	#=> 9999

Now I understand James' question. The above is NOT what I would have 
expected, and at odds with the Pickaxe quote. It means that the 
following code does not work like the equivalent would in something 
like ASP:

	require 'erb'
	erb = ERB.new <<ENDERB
	<h1>Hello, World</h1>
	
	<p>I like cheese because:</p>
	<ol>
	<%
	reasons = [ "It's bad for me", "It is tasty", "And so yes" ]
	reasons.each{ |reason|
		puts "\t<li>#{reason}</li>"
	}
	%>
	</ol>
	Done.
	ENDERB
	
	puts erb.result( binding )

Er...in fact, the above doesn't run at all, oddly.
	tmp.rb:12: undefined local variable or method `reason' for main:Object 
(NameError)
	
Changing the block to:
	<%
	3.times{ puts "<li>Just because.</li>" }
	%>

produces the final output:
	#=> <li>Just because.</li>
	#=> <li>Just because.</li>
	#=> <li>Just because.</li>
	#=> <h1>Hello, World</h1>
	#=>
	#=> <p>I like cheese because:</p>
	#=> <ol>
	#=>
	#=> </ol>
	#=> Done.

...which is clearly not what is desired. Perhaps there's some way to 
run IRB that hijacks STDOUT that I don't know about.

Finally, to be clear, the following DOES work:
	require 'erb'
	erb = ERB.new <<ENDERB
	<h1>Hello, World</h1>
	
	<p>I like cheese because:</p>
	<ol>
		<%
		reasons = [ "It's bad for me", "It is tasty", "And so yes" ]
		reasons.each{ |reason|
		%>
			<li><%=reason%></li><%
		}
		%>
	</ol>
	Done.
	ENDERB
	
	puts erb.result( binding )

outputting:
	#=> <h1>Hello, World</h1>
	#=>
	#=> <p>I like cheese because:</p>
	#=> <ol>
	#=> 	
	#=> 		<li>It's bad for me</li>
	#=> 		<li>It is tasty</li>
	#=> 		<li>And so yes</li>
	#=> </ol>
	#=> Done.