Class: Inversion::Template::DefaultTag

Inherits:
CodeTag show all
Defined in:
lib/inversion/template/defaulttag.rb

Overview

Inversion ‘default’ tag.

The default tag sets the default value of an attribute to a constant, the value of another attribute, or the results of evaluating a methodchain on an attribute.

Syntax

<!-- Set a default width that can be overridden by the controller -->
<?default width to 120 ?>
<?default employees to [] ?>

<!-- Default an attribute to the value of a second attribute -->
<?default content to body ?>

<!-- Set the title to the employee's name if it hasn't been set explicitly -->
<?default title to "%s, %s" % [ employee.lastname, employee.firstname ] ?>

Constant Summary

Constants inherited from Tag

Tag::TAG_PLUGIN_PATTERN

Instance Attribute Summary collapse

Attributes inherited from CodeTag

#body, #identifiers

Attributes inherited from Tag

#body

Attributes inherited from Node

#colnum, #linenum

Instance Method Summary collapse

Methods inherited from CodeTag

inherit_tag_patterns, tag_pattern, tag_patterns

Methods included from AbstractClass

included

Methods included from AbstractClass::ClassMethods

#inherited, #pure_virtual

Methods inherited from Tag

create, #derivatives, inherited, load, load_all, #tagname, types, #types

Methods included from MethodUtilities

#singleton_attr_accessor, #singleton_attr_reader, #singleton_attr_writer

Methods inherited from Node

#after_appending, #after_rendering, #before_appending, #is_container?, #location

Constructor Details

#initialize(body, linenum = nil, colnum = nil) ⇒ DefaultTag

Create a new DefaultTag with the given name, which should be a valid Ruby identifier.



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# File 'lib/inversion/template/defaulttag.rb', line 60

def initialize( body, linenum=nil, colnum=nil )
  @name        = nil
  @methodchain = nil
  @literal     = nil
  @format      = nil

  super

  # Add an identifier for the tag name
  self.identifiers << self.name.to_sym
end

Instance Attribute Details

#format ⇒ Object

the format string used to format the attribute in the template (if one was declared)



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# File 'lib/inversion/template/defaulttag.rb', line 82

def format
  @format
end

#literal ⇒ Object

The literal, if the tag had one (as opposed to an attribute or methodchain)



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# File 'lib/inversion/template/defaulttag.rb', line 85

def literal
  @literal
end

#methodchain ⇒ Object

the chain of methods that should be called (if any).



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# File 'lib/inversion/template/defaulttag.rb', line 88

def methodchain
  @methodchain
end

#name ⇒ Object

the name of the attribute



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# File 'lib/inversion/template/defaulttag.rb', line 78

def name
  @name
end

Instance Method Details

#as_comment_body ⇒ Object

Render the tag as the body of a comment, suitable for template debugging.



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# File 'lib/inversion/template/defaulttag.rb', line 92

def as_comment_body
  comment = "%s '%s': { " % [ self.tagname, self.name ]
  if self.methodchain
    comment << "template.%s%s" % [ self.identifiers.first, self.methodchain ]
  else
    comment << self.literal
  end
  comment << " }"
  comment << " with format: %p" % [ self.format ] if self.format

  return comment
end

#before_rendering(renderstate) ⇒ Object

Set the specified value (if it’s nil) before rendering.



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# File 'lib/inversion/template/defaulttag.rb', line 107

def before_rendering( renderstate )
  existing_value = renderstate.attributes[ self.name.to_sym ]
  unless existing_value.nil?
    self.log.info "Not defaulting %s: already set to %p" %
      [ self.name, existing_value ]
    return nil
  end

  default = nil
  if chain = self.methodchain
    self.log.debug "Using methodchain %p to set default for %p" %
      [ chain, self.name ]
    default = renderstate.eval( 'self' + '.' + self.identifiers.first + chain )
  else
    self.log.debug "Using literal %p to set default for %p" %
      [ self.literal, self.name ]
    default = renderstate.eval( self.literal )
    default = self.format % default if self.format
  end

  self.log.debug "  default value: %p" % [ default ]
  renderstate.attributes[ self.name.to_sym ] = default
end

#render(renderstate) ⇒ Object

Render as the empty string.



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# File 'lib/inversion/template/defaulttag.rb', line 133

def render( renderstate )
  return ''
end