Class: Inversion::Template::RescueTag

Inherits:
Tag
  • Object
show all
Defined in:
lib/inversion/template/rescuetag.rb

Overview

Inversion ‘rescue’ tag.

This tag adds a logical switch to a BeginTag. If rendering any of the BeginTag’s nodes raises an exception of the type specified by the RescueTag, the nodes following the RescueTag are rendered instead.

Syntax

<?begin ?>
    <?for employee in employees.all ?>
        <?attr employee.name ?> --> <?attr employee.title ?>
    <?end for?>
<?rescue DatabaseError => err ?>
    Oh no!! I can't talk to the database for some reason.  The
    error was as follows:

        <?attr err.message ?>

<?end?>

Constant Summary

Constants inherited from Tag

Tag::TAG_PLUGIN_PATTERN

Instance Attribute Summary collapse

Attributes inherited from Tag

#body

Attributes inherited from Node

#colnum, #linenum

Instance Method Summary collapse

Methods inherited from Tag

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

Methods included from MethodUtilities

#singleton_attr_accessor, #singleton_attr_reader, #singleton_attr_writer

Methods included from AbstractClass

included

Methods included from AbstractClass::ClassMethods

#inherited, #pure_virtual

Methods inherited from Node

#after_appending, #after_rendering, #as_comment_body, #before_rendering, #is_container?, #location, #render

Constructor Details

#initialize(body = '', linenum = nil, colnum = nil) ⇒ RescueTag

Overridden to default body to nothing, and raise an error if it has one.



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# File 'lib/inversion/template/rescuetag.rb', line 32

def initialize( body='', linenum=nil, colnum=nil ) # :notnew:
  super
  @exception_types = parse_exception_types( self.body )
end

Instance Attribute Details

#exception_types ⇒ Object (readonly)

The exception classes the rescue will handle (an Array of Class objects)



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# File 'lib/inversion/template/rescuetag.rb', line 43

def exception_types
  @exception_types
end

Instance Method Details

#before_appending(parsestate) ⇒ Object

Parsing callback – check to be sure the node tree can have the ‘rescue’ tag appended to it.

Raises:



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# File 'lib/inversion/template/rescuetag.rb', line 48

def before_appending( parsestate )
  condtag = parsestate.node_stack.reverse.find do |node|
    case node

    # If there was a previous 'begin', the 'rescue' belongs to it. Also
    # allow it to be appended to a 'comment' section so you can comment out a
    # rescue clause without commenting out the begin
    when Inversion::Template::BeginTag,
         Inversion::Template::CommentTag
      break node

    # If it's some other kind of container, it's an error
    when Inversion::Template::ContainerTag
      raise Inversion::ParseError, "'%s' tags can't have '%s' clauses" %
        [ node.tagname.downcase, self.tagname.downcase ]
    end
  end

  # If there wasn't a valid container, it's an error too
  raise Inversion::ParseError, "orphaned '%s' tag" % [ self.tagname.downcase ] unless condtag
end