def visit_mixin(node)
include_loop = true
handle_include_loop!(node) if @stack.any? {|e| e[:name] == node.name}
include_loop = false
@stack.push(:filename => node.filename, :line => node.line, :name => node.name)
raise Sass::SyntaxError.new("Undefined mixin '#{node.name}'.") unless mixin = @environment.mixin(node.name)
if node.children.any? && !mixin.has_content
raise Sass::SyntaxError.new(%Q{Mixin "#{node.name}" does not accept a content block.})
end
args = node.args.map {|a| a.perform(@environment)}
keywords = Sass::Util.map_hash(node.keywords) {|k, v| [k, v.perform(@environment)]}
splat = node.splat.perform(@environment) if node.splat
self.class.perform_arguments(mixin, args, keywords, splat) do |env|
env.caller = Sass::Environment.new(@environment)
env.content = node.children if node.has_children
trace_node = Sass::Tree::TraceNode.from_node(node.name, node)
with_environment(env) {trace_node.children = mixin.tree.map {|c| visit(c)}.flatten}
trace_node
end
rescue Sass::SyntaxError => e
unless include_loop
e.modify_backtrace(:mixin => node.name, :line => node.line)
e.add_backtrace(:line => node.line)
end
raise e
ensure
@stack.pop unless include_loop
end