engine.rb in macros4cuke-0.4.03

- old
+ new

@@ -1,12 +1,16 @@
 # File: engine.rb
-# Purpose: Implementation of the MacroStep class.
+# Purpose: Implementation of the Engine class.
 
 require 'strscan' # Use the StringScanner for lexical analysis.
 require_relative '../exceptions' # Load the custom exception classes.
 
+require_relative 'template-element'
+require_relative 'placeholder'
+require_relative 'section'  # Load the Section and ConditionalSection
 
+
 module Macros4Cuke # Module used as a namespace
 
 
 # Module containing all classes implementing the simple template engine
 # used internally in Macros4Cuke.  
@@ -78,173 +82,9 @@
   def render(aContextObject, theLocals)
     return "\n"
   end
 end # class
 
-
-# Base class used internally by the template engine.  
-# The generalization of any element from a template that has one variable
-# whose actual value influences the rendition.
-class UnaryElement
-  # The name of the placeholder/variable.
-  attr_reader(:name)
-  
-  # @param aVarName [String] The name of the placeholder from a template.
-  def initialize(aVarName)
-    @name = aVarName
-  end
-
-  protected
-
-  # This method has the same signature as the {Engine#render} method.
-  # @return [Object] The actual value from the locals or context
-  # that is assigned to the variable.
-  def retrieve_value_from(aContextObject, theLocals)
-    actual_value = theLocals[name]
-    if actual_value.nil? && aContextObject.respond_to?(name.to_sym)
-      actual_value = aContextObject.send(name.to_sym)
-    end
-    
-    return actual_value
-  end  
-  
-end # class
-
-
-
-# Class used internally by the template engine.  
-# Represents a named placeholder in a template, that is, 
-# a name placed between <..> in the template.  
-# At rendition, a placeholder is replaced by the text value
-# that is associated with it. 
-class Placeholder < UnaryElement
-
-  public
-
-  # Render the placeholder given the passed arguments.
-  # This method has the same signature as the {Engine#render} method.
-  # @return [String] The text value assigned to the placeholder. 
-  #   Returns an empty string when no value is assigned to the placeholder.
-  def render(aContextObject, theLocals)
-    actual_value = retrieve_value_from(aContextObject, theLocals)
-    
-    result = case actual_value
-      when NilClass
-        ''
-      
-      when Array
-        # TODO: Move away from hard-coded separator.
-        actual_value.join('<br/>')
-        
-      when String
-        actual_value
-      else
-        actual_value.to_s
-    end
-        
-    return result
-  end  
-
-end # class
-
-
-# Base class used internally by the template engine.  
-# Represents a section in a template, that is, 
-# a set of template elements for which its rendition depends
-# on the value of a variable.
-class Section  < UnaryElement
-  # The child elements of the section
-  attr_reader(:children)
-  
-  # @param aVarName [String] The name of the placeholder from a template.
-  def initialize(aVarName)
-    super(aVarName)
-    @children = []
-  end
-
-  public
-
-  # Add a child element as member of the section
-  def add_child(aChild)
-    children << aChild
-  end
-  
-  # Retrieve all placeholder names that appear in the template.
-  # @return [Array] The list of placeholder names.
-  def variables()
-    all_vars = children.each_with_object([]) do |a_child, subResult|
-      case a_child
-      when Placeholder
-        subResult << a_child.name
-      when Section
-        subResult.concat(a_child.variables)
-      else
-        # Do nothing
-      end
-    end
-    
-    return all_vars.flatten.uniq
-  end
-
-
-  # Render the placeholder given the passed arguments.
-  # This method has the same signature as the {Engine#render} method.
-  # @return [String] The text value assigned to the placeholder. 
-  #   Returns an empty string when no value is assigned to the placeholder.
-  def render(aContextObject, theLocals)
-    msg = "Method Section.#{__method__} must be implemented in subclass."
-    fail(NotImplementedError, msg)
-  end    
-
-end # class
-
-
-# A specialized section in a template for which its rendition
-# depends on the (in)existence of an actual value bound to the variable name.
-class ConditionalSection < Section
-  # A boolean that indicates whether the rendition condition is 
-  # the existence of a value for the variable (true)
-  # or its inexistence (false).
-  attr_reader(:existence)
-
-  # @param aVarName [String] The name of the placeholder from a template.
-  # @param renderWhenExisting [boolean] When true, render the children elements
-  #   if a value exists for the variable.  
-  def initialize(aVarName, renderWhenExisting = true)
-    super(aVarName)
-    @existence = renderWhenExisting
-  end
-  
-  public
-
-  # Render the placeholder given the passed arguments.
-  # This method has the same signature as the {Engine#render} method.
-  # @return [String] The text value assigned to the placeholder. 
-  #   Returns an empty string when no value is assigned to the placeholder.
-  def render(aContextObject, theLocals)
-    actual_value = retrieve_value_from(aContextObject, theLocals)
-    if (!actual_value.nil? && existence) || (actual_value.nil? && !existence)
-      # Let render the children
-      result = children.each_with_object('') do |a_child, sub_result|
-        sub_result << a_child.render(aContextObject, theLocals)
-      end
-    else
-      result = ''
-    end
-    
-    return result
-  end
-
-
-  # @return [String] The original text representation of the tag.
-  def to_s()
-    return "<?#{name}>"
-  end
-
-end # class
-
-
-SectionEndMarker = Struct.new(:name)
 
 
 # A very simple implementation of a templating engine.  
 # Earlier versions of Macros4Cuke relied on the logic-less 
 # Mustache template engine.  