Allow mixins and functions to be defined in nested contexts.

Closes #427

doc-src/SASS_CHANGELOG.md

@@ -94,6 +94,10 @@ that make use of `@media` and other directives dynamically.
 
 ### Smaller Improvements
 
+* Mixins and functions may now be defined in a nested context, for example
+  within `@media` rules. This also allows files containing them to be imported
+  in such contexts.
+
 * Previously, only the `:-moz-any` selector was supported; this has been
   expanded to support any vendor prefix, as well as the plain `:any` selector.
 

lib/sass/tree/visitors/check_nesting.rb

@@ -73,20 +73,6 @@ def invalid_extend_parent?(parent, child)
     end
   end
 
-  def invalid_function_parent?(parent, child)
-    "Functions may only be defined at the root of a document." unless parent.is_a?(Sass::Tree::RootNode)
-  end
-
-  VALID_FUNCTION_CHILDREN = [
-    Sass::Tree::CommentNode,  Sass::Tree::DebugNode, Sass::Tree::ReturnNode,
-    Sass::Tree::VariableNode, Sass::Tree::WarnNode
-  ] + CONTROL_NODES
-  def invalid_function_child?(parent, child)
-    unless is_any_of?(child, VALID_FUNCTION_CHILDREN)
-      "Functions can only contain variable declarations and control directives."
-    end
-  end
-
   INVALID_IMPORT_PARENTS = CONTROL_NODES +
     [Sass::Tree::MixinDefNode, Sass::Tree::MixinNode]
   def invalid_import_parent?(parent, child)
@@ -95,18 +81,32 @@ def invalid_import_parent?(parent, child)
     end
     return if parent.is_a?(Sass::Tree::RootNode)
     return "CSS import directives may only be used at the root of a document." if child.css_import?
-    # If this is a nested @import, we need to make sure it doesn't have anything
-    # that's legal at top-level but not in the current context (e.g. mixin defs).
-    child.imported_file.to_tree.children.each {|c| visit(c)}
-    nil
   rescue Sass::SyntaxError => e
     e.modify_backtrace(:filename => child.imported_file.options[:filename])
     e.add_backtrace(:filename => child.filename, :line => child.line)
     raise e
   end
 
   def invalid_mixindef_parent?(parent, child)
-    "Mixins may only be defined at the root of a document." unless parent.is_a?(Sass::Tree::RootNode)
+    unless (@parents.map {|p| p.class} & INVALID_IMPORT_PARENTS).empty?
+      return "Mixins may not be defined within control directives or other mixins."
+    end
+  end
+
+  def invalid_function_parent?(parent, child)
+    unless (@parents.map {|p| p.class} & INVALID_IMPORT_PARENTS).empty?
+      return "Functions may not be defined within control directives or other mixins."
+    end
+  end
+
+  VALID_FUNCTION_CHILDREN = [
+    Sass::Tree::CommentNode,  Sass::Tree::DebugNode, Sass::Tree::ReturnNode,
+    Sass::Tree::VariableNode, Sass::Tree::WarnNode
+  ] + CONTROL_NODES
+  def invalid_function_child?(parent, child)
+    unless is_any_of?(child, VALID_FUNCTION_CHILDREN)
+      "Functions can only contain variable declarations and control directives."
+    end
   end
 
   VALID_PROP_CHILDREN = [Sass::Tree::CommentNode, Sass::Tree::PropNode, Sass::Tree::MixinNode] + CONTROL_NODES

lib/sass/tree/visitors/perform.rb

@@ -113,7 +113,7 @@ def visit_for(node)
 
   # Loads the function into the environment.
   def visit_function(node)
-    @environment.set_function(node.name,
+    @environment.set_local_function(node.name,
       Sass::Callable.new(node.name, node.args, @environment, node.children, !:has_content))
     []
   end
@@ -155,7 +155,7 @@ def visit_import(node)
 
   # Loads a mixin into the environment.
   def visit_mixindef(node)
-    @environment.set_mixin(node.name,
+    @environment.set_local_mixin(node.name,
       Sass::Callable.new(node.name, node.args, @environment, node.children, node.has_content))
     []
   end

test/sass/engine_test.rb

@@ -73,7 +73,7 @@ class SassEngineTest < Test::Unit::TestCase
     "=foo\n  :color red\n.bar\n  +bang" => "Undefined mixin 'bang'.",
     "=foo\n  :color red\n.bar\n  +bang_bop" => "Undefined mixin 'bang_bop'.",
     "=foo\n  :color red\n.bar\n  +bang-bop" => "Undefined mixin 'bang-bop'.",
-    ".bar\n  =foo\n    :color red\n" => ["Mixins may only be defined at the root of a document.", 2],
+    ".foo\n  =foo\n    :color red\n.bar\n  +foo" => "Undefined mixin 'foo'.",
     "    a\n  b: c" => ["Indenting at the beginning of the document is illegal.", 1],
     " \n   \n\t\n  a\n  b: c" => ["Indenting at the beginning of the document is illegal.", 4],
     "a\n  b: c\n b: c" => ["Inconsistent indentation: 1 space was used for indentation, but the rest of the document was indented using 2 spaces.", 3],
@@ -105,7 +105,6 @@ class SassEngineTest < Test::Unit::TestCase
     "@function foo($)\n  @return 1" => ['Invalid CSS after "(": expected variable (e.g. $foo), was "$)"', 1],
     "@function foo()\n  @return" => 'Invalid @return: expected expression.',
     "@function foo()\n  @return 1\n    $var: val" => 'Illegal nesting: Nothing may be nested beneath return directives.',
-    "foo\n  @function bar()\n    @return 1" => ['Functions may only be defined at the root of a document.', 2],
     "@function foo($a)\n  @return 1\na\n  b: foo()" => 'Function foo is missing argument $a',
     "@function foo()\n  @return 1\na\n  b: foo(2)" => 'Wrong number of arguments (1 for 0) for `foo\'',
     "@function foo()\n  @return 1\na\n  b: foo($a: 1)" => "Function foo doesn't have an argument named $a",
@@ -274,7 +273,7 @@ def test_exception_location
   end
 
   def test_imported_exception
-    [1, 2, 3, 4, 5].each do |i|
+    [1, 2, 3, 4].each do |i|
       begin
         Sass::Engine.new("@import bork#{i}", :load_paths => [File.dirname(__FILE__) + '/templates/']).render
       rescue Sass::SyntaxError => err
@@ -296,7 +295,7 @@ def test_imported_exception
   end
 
   def test_double_imported_exception
-    [1, 2, 3, 4, 5].each do |i|
+    [1, 2, 3, 4].each do |i|
       begin
         Sass::Engine.new("@import nested_bork#{i}", :load_paths => [File.dirname(__FILE__) + '/templates/']).render
       rescue Sass::SyntaxError => err
@@ -723,24 +722,6 @@ def test_import_in_rule
 SASS
   end
 
-  def test_nested_import_with_toplevel_constructs
-    Sass::Engine.new(".foo\n  @import importee", :load_paths => [File.dirname(__FILE__) + '/templates/']).render
-  rescue Sass::SyntaxError => err
-    assert_equal(3, err.sass_line)
-    assert_match(/(\/|^)importee\.sass$/, err.sass_filename)
-
-    assert_hash_has(err.sass_backtrace.first,
-      :filename => err.sass_filename, :line => err.sass_line)
-
-    assert_nil(err.sass_backtrace[1][:filename])
-    assert_equal(2, err.sass_backtrace[1][:line])
-
-    assert_match(/(\/|^)importee\.sass:3$/, err.backtrace.first)
-    assert_equal("(sass):2", err.backtrace[1])
-  else
-    assert(false, "Exception not raised for importing mixins nested")
-  end
-
   def test_units
     renders_correctly "units"
   end

test/sass/scss/scss_test.rb

@@ -1073,17 +1073,83 @@ def test_random_directive_interpolation
 SCSS
   end
 
+  def test_nested_mixin_def
+    assert_equal <<CSS, render(<<SCSS)
+foo {
+  a: b; }
+CSS
+foo {
+  @mixin bar {a: b}
+  @include bar; }
+SCSS
+  end
+
+  def test_nested_mixin_shadow
+    assert_equal <<CSS, render(<<SCSS)
+foo {
+  c: d; }
+
+baz {
+  a: b; }
+CSS
+@mixin bar {a: b}
+
+foo {
+  @mixin bar {c: d}
+  @include bar;
+}
+
+baz {@include bar}
+SCSS
+  end
+
+  def test_nested_function_def
+    assert_equal <<CSS, render(<<SCSS)
+foo {
+  a: 1; }
+
+bar {
+  b: foo(); }
+CSS
+foo {
+  @function foo() {@return 1}
+  a: foo(); }
+
+bar {b: foo()}
+SCSS
+  end
+
+  def test_nested_function_shadow
+    assert_equal <<CSS, render(<<SCSS)
+foo {
+  a: 2; }
+
+baz {
+  b: 1; }
+CSS
+@function foo() {@return 1}
+
+foo {
+  @function foo() {@return 2}
+  a: foo();
+}
+
+baz {b: foo()}
+SCSS
+  end
+
   ## Errors
 
-  def test_mixin_defs_only_at_toplevel
+  def test_nested_mixin_def_is_scoped
     render <<SCSS
 foo {
   @mixin bar {a: b}}
+bar {@include bar}
 SCSS
     assert(false, "Expected syntax error")
   rescue Sass::SyntaxError => e
-    assert_equal "Mixins may only be defined at the root of a document.", e.message
-    assert_equal 2, e.sass_line
+    assert_equal "Undefined mixin 'bar'.", e.message
+    assert_equal 3, e.sass_line
   end
 
   def test_rules_beneath_properties