[Sass] Respect --trace in bin/sass -i.

lib/haml/exec.rb

@@ -195,7 +195,7 @@ END
         if @options[:interactive]
           require 'sass'
           require 'sass/repl'
-          ::Sass::Repl.run
+          ::Sass::Repl.new(@options).run
           return
         end
 

lib/sass/repl.rb

@@ -1,43 +1,50 @@
 require 'readline'
 
 module Sass
-  module Repl
-    class << self
-      def run
-        environment = Environment.new
-        environment.set_var('important', Script::String.new('!important'))
-        @line = 0
-        loop do
-          @line += 1
-          unless text = Readline.readline('>> ')
-            puts
-            return
-          end
+  class Repl
+    def initialize(options = {})
+      @options = options
+    end
 
-          Readline::HISTORY << text
-          parse_input(environment, text)
+    def run
+      environment = Environment.new
+      environment.set_var('important', Script::String.new('!important'))
+      @line = 0
+      loop do
+        @line += 1
+        unless text = Readline.readline('>> ')
+          puts
+          return
         end
+
+        Readline::HISTORY << text
+        parse_input(environment, text)
       end
+    end
 
-      private
+    private
 
-      def parse_input(environment, text)
-        case text
-        when Script::MATCH
-          name = $1
-          guarded = $2 == '||='
-          val = Script::Parser.parse($3, @line, text.size - $3.size)
+    def parse_input(environment, text)
+      case text
+      when Script::MATCH
+        name = $1
+        guarded = $2 == '||='
+        val = Script::Parser.parse($3, @line, text.size - $3.size)
 
-          unless guarded && environment.var(name)
-            environment.set_var(name, val.perform(environment))
-          end
-
-          p environment.var(name)
-        else
-          p Script::Parser.parse(text, @line, 0).perform(environment)
+        unless guarded && environment.var(name)
+          environment.set_var(name, val.perform(environment))
+        end
+
+        p environment.var(name)
+      else
+        p Script::Parser.parse(text, @line, 0).perform(environment)
+      end
+    rescue Sass::SyntaxError => e
+      puts "SyntaxError: #{e.message}"
+      if @options[:trace]
+        e.backtrace.each do |e|
+          puts "\tfrom #{e}"
         end
-      rescue Sass::SyntaxError => e
-        puts "SyntaxError: #{e.message}"
       end
     end
   end