Rakefile + ERB with better error handling

Rakefile

require 'yaml'
require 'erb'

# render a template
# @param [String] s template
# @param [Binding] ctx binding context
# @return [String] render output
def render(s, ctx)
  begin
   erb = ERB.new(s)
   m = erb.result(ctx)
   return m
  rescue => e
   puts 'ERROR: '
   lineno = e.backtrace[0].split(':')[1].to_i
   puts "  line: #{lineno}"
   puts "  text: #{s.split("\n")[lineno-1].strip}"
   puts " error: #{e.to_s}"
   return nil
  end
end

task :default => [:awesome]

def create_report
  n = 'ok'

  s = %Q(
hello world
<%= bad_call %>
test: <%= n %>
)

  return render(s, binding)
end

task :awesome => :compile do
  puts "report: " + create_report
end

task :compile do
  sh "echo 'do compile'"
end