lib/mini_hiera.rb in mini_hiera-0.1.2 vs lib/mini_hiera.rb in mini_hiera-0.2.0.pre1

@@ -10,25 +10,46 @@
 
 class MiniHiera
   CircularReferenceError = Class.new(RuntimeError)
   KeyNotFoundError = Class.new(RuntimeError)
 
-  attr_reader :config, :options
+  attr_reader :config, :options, :context_functions, :value_functions
   def initialize(config, options={})
     @config = config
     @options = options
+    @context_functions = {}
+    @value_functions = {}
   end
 
+  def context_function(name, &impl)
+    @context_functions[name] = impl
+  end
+  def value_function(name, &impl)
+    @value_functions[name] = impl
+  end
+
   class Context
     def initialize(hiera, data, options)
       @hiera, @data, @options = hiera, data, options
     end
 
     def postprocess(value)
       if value.is_a?(String)
         value.gsub(/\%\{([^}]+)\}/) do |match|
-          fetch($1)
+          replace = $1
+          _, block = @hiera.value_functions.find { |name, _| replace =~ /^#{name}\((.*)\)$/ }
+          if block
+            argument = $1
+            argument = if argument =~ /^["'](.*)['"]$/
+              $1
+            else
+              fetch(argument)
+            end
+            block.call(argument)
+          else
+            fetch(replace)
+          end
         end
       elsif value.is_a?(Hash)
         Hash[value.map { |k,v| [k, postprocess(v)] }]
       elsif value.is_a?(Array)
         value.map { |v| postprocess(v) }
@@ -64,25 +85,41 @@
 
       default_block ||= lambda { default == DefaultObject ? raise(KeyNotFoundError, [" ** Unknown key '#{key}'", error_message_suffix].join(" ")) : default }
 
       default_block_wrapper = lambda { |*_| default_block.arity == 0 ? default_block.call : default_block.call(key) }
 
-      data = hiera_data
+      # is the first key a function that yields a tree?
+      split_key = key.split(".")
+      _, block = @hiera.context_functions.find { |name, block| split_key.first =~ /^#{name}\(([^\)]*)\)$/ }
+      argument = $1
+      
 
-      key.split(".").each do |k|
-        if data.is_a?(Array)
-          raise TypeError, "no implicit conversion of String into Integer" unless k.to_i.to_s == k
-          data = data[k.to_i]
-        elsif data.is_a?(Hash)
-          data = data.fetch(k, &default_block_wrapper)
+      if !!block
+        split_key.shift
+        argument = if argument =~ /^["'](.*)['"]$/
+          $1
         else
-          data = default_block_wrapper.call
-          break
+          fetch(argument)
         end
-      end
 
-      detect_circular_interpolation(key) do
-        postprocess(data)
+        block.call(argument).fetch(split_key.join("."))
+      else
+        data = hiera_data
+        split_key.each do |k|
+          if data.is_a?(Array)
+            raise TypeError, "no implicit conversion of String into Integer" unless k.to_i.to_s == k
+            data = data[k.to_i]
+          elsif data.is_a?(Hash)
+            data = data.fetch(k, &default_block_wrapper)
+          else
+            data = default_block_wrapper.call
+            break
+          end
+        end
+
+        detect_circular_interpolation(key) do
+          postprocess(data)
+        end
       end
     end
 
     def [](key)
       fetch(key)