converting puppet erb template to epp - templates

Question

I'm trying to convert erb templates to epp (new company policy) and there isn't a lot of documentation on epp yet.
Here's what i have in erb:
<% filter.select{|x| x != 'filtertype'}.sort.each do |key, element| -%>
<%= key %>: '<%= element %>'
<% end -%>
it works great! however i have to find the equivalent for epp. I can get the "each" part to work, but the select method isn't working for me.
I'm stumped!
I tried something like:
<% $filter.select { |$x| $x != 'filtertype'}.each |$key, $element| { -%>
<%= $key %>: '<%= $element %>'
<% } -%>
this in particular errors on '|' for the $x.
I also tried:
<% $filter.select |$x| {$x != 'filtertype'}.each |$key, $element| { -%>
<%= $key %>: '<%= $element %>'
<% } -%>
but that gives me something like "Error while evaluating a Method call, select(): Wrong number of arguments given 1 for 3"
I've tried moving around the {} and changing them to (), but no luck.
does anyone have any ideas?
Thanks!

Answer 1

As Dominic Cleal mentions in the comment, select() is not a Puppet function, however filter() is and is the equivalent of select in Ruby.
Therefore:
Given a class:
class foo () {
# Some test data.
$filter = {
'filtertype' => 'foo',
'apples' => 1,
'bananas' => 2,
}
# How to declare the ERB template for comparison:
file { '/foo':
ensure => file,
content => template('foo/mytemplate.erb'),
}
# How to declare the EPP template for comparison:
file { '/bar':
ensure => file,
content => epp('foo/mytemplate.epp', {'filter' => $filter}),
}
}
Content of the ERB file exactly as given in the question:
<% #filter.select{|x| x != 'filtertype'}.sort.each do |key, element| -%>
<%= key %>: '<%= element %>'
<% end -%>
Content of an equivalent EPP file:
<% | Hash $filter | -%>
<% include stdlib -%>
<% $filter.keys.sort.filter |$k| {$k != 'filtertype'}.each |$k| { -%>
<%= $k %>: '<%= $filter[$k] %>'
<% } -%>
Things to note:
1) You need include stdlib to access the keys and sort functions.
2) The variable name $filter now clashes with the built-in Puppet function filter(), which is syntactically fine, but confusing, so you would consider renaming the $filter variable to something else for clarity.
Also, if you don't care about sorting the keys, then I could make what you tried work using:
<% | Hash $filter | -%>
<% $filter.filter |$k| {$k[0] != 'filtertype'}.each |$k, $v| { -%>
<%= $k %>: '<%= $v %>'
<% } -%>
See also here where I just answered a similar question.