Sass mixin recursion; @include loop

问题

Does anyone know if it's possible to revert Sass's functionality, to prevent the "bug-fix"¹ that was implemented to prevent @include recursion?

The message is:

Syntax error: An @include loop has been found: <mixin-name> includes itself

This was "fixed"¹ in 3.0.5, and I'd prefer not to (read: I can't) downgrade that far. I unfortunately don't know enough Ruby to go sifting through the source, and while I'm making time to change that, it doesn't help me now.

So, is it possible² to revert this functionality to that of pre-3.0.5 without having to downgrade; is there a re-patch floating around somewhere? I haven't been able to find one.

Edit: While I've answered this myself now, I'm still open to better answers; specifically, more portable solutions since now the Sass files will break anywhere else (anywhere that isn't pre-3.0.5)

_{¹ Quotes used to indicate I don't think this is a fix. I think it is a break; I'll take that up with those responsible though.
²I know its possible, but I mean specifically for someone with no practical experience with Ruby. I'm learning Ruby!}

回答1:

Okay, there's a cleaner way apply your hack: monkey-patching with Compass.

It will let you share your project safely and everybody else will be able to compile it without modifying their own SASS compilers.

1)

Create sass-visit-mixin-monkey-patch.rb next to compass.rb and apply your hack from there:

class Sass::Tree::Visitors::Perform < Sass::Tree::Visitors::Base
  # Runs a mixin.
  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
end

2)

Require the monkey patch from the config.rb:

# Enabling mixin recursion by applying a monkey patch to SASS compiler
require "./sass-visit-mixin-monkey-patch"

3)

Compile your project with compass compile.

回答2:

You know, I know enough Ruby to comment out a line or two ;)

At .\lib\sass\tree\visitors\perform.rb : 249 just comment:

# Runs a mixin.
def visit_mixin(node)
  include_loop = true
  handle_include_loop!(node) if @stack.any? {|e| e[:name] == node.name}
  include_loop = false

Into:

# Runs a mixin.
def visit_mixin(node)
  # include_loop = true
  # handle_include_loop!(node) if @stack.any? {|e| e[:name] == node.name}
  include_loop = false

Suddenly, rainbows of glorious recursion.

来源：https://stackoverflow.com/questions/15531004/sass-mixin-recursion-include-loop

标签

css

ruby

recursion

Sass