Class: Sass::Tree::Visitors::Base Abstract

Inherits:
Object
  • Object
show all
Defined in:
/Users/ceppstei/Projects/sass-lang/.sass/lib/sass/tree/visitors/base.rb

Overview

This class is abstract.

The abstract base class for Sass visitors. Visitors should extend this class, then implement visit_* methods for each node they care about (e.g. visit_rule for RuleNode or visit_for for ForNode). These methods take the node in question as argument. They may yield to visit the child nodes of the current node.

Note: due to the unusual nature of IfNode, special care must be taken to ensure that it is properly handled. In particular, there is no built-in scaffolding for dealing with the return value of @else nodes.

Direct Known Subclasses

CheckNesting, Convert, Cssize, DeepCopy, Extend, Perform, SetOptions, ToCss

Class Method Summary (collapse)

Instance Method Summary (collapse)

Class Method Details

+ (String) node_name(node) (protected)

Returns the name of a node as used in the visit_* method.

Parameters:

Returns:

  • (String) —

    The name.



59
60
61
62
 
# File '/Users/ceppstei/Projects/sass-lang/.sass/lib/sass/tree/visitors/base.rb', line 59

def self.node_name(node)
  Sass::Util.deprecated(self, "Call node.class.node_name instead.")
  node.class.node_name
end

+ (Object) visit(root)

Runs the visitor on a tree.

Parameters:

  • root (Tree::Node) —

    The root node of the Sass tree.

Returns:

  • (Object) —

    The return value of #visit for the root node.



23
24
25
 
# File '/Users/ceppstei/Projects/sass-lang/.sass/lib/sass/tree/visitors/base.rb', line 23

def self.visit(root)
  new.send(:visit, root)
end

Instance Method Details

- (Object) visit(node) (protected)

Runs the visitor on the given node. This can be overridden by subclasses that need to do something for each node.

Parameters:

Returns:

  • (Object) —

    The return value of the visit_* method for this node.



34
35
36
37
38
39
40
 
# File '/Users/ceppstei/Projects/sass-lang/.sass/lib/sass/tree/visitors/base.rb', line 34

def visit(node)
  if respond_to?(node.class.visit_method, true)
    send(node.class.visit_method, node) {visit_children(node)}
  else
    visit_children(node)
  end
end

- (Array<Object>) visit_children(parent) (protected)

Visit the child nodes for a given node. This can be overridden by subclasses that need to do something with the child nodes’ return values.

This method is run when visit_* methods yield, and its return value is returned from the yield.

Parameters:

  • parent (Tree::Node) —

    The parent node of the children to visit.

Returns:

  • (Array<Object>) —

    The return values of the visit_* methods for the children.



51
52
53
 
# File '/Users/ceppstei/Projects/sass-lang/.sass/lib/sass/tree/visitors/base.rb', line 51

def visit_children(parent)
  parent.children.map {|c| visit(c)}
end

- visit_if(node) (protected)

yields, then runs the visitor on the @else clause if the node has one. This exists to ensure that the contents of the @else clause get visited.



66
67
68
69
70
 
# File '/Users/ceppstei/Projects/sass-lang/.sass/lib/sass/tree/visitors/base.rb', line 66

def visit_if(node)
  yield
  visit(node.else) if node.else
  node
end