Revert "Merge pull request #466 from Shopify/remove-expression-cache"

This reverts commit d9ae36ec40, reversing
changes made to 2da9d49478.

lib/liquid/condition.rb

@@ -3,7 +3,7 @@ module Liquid
   #
   # Example:
   #
-  #   c = Condition.new(1, '==', 1)
+  #   c = Condition.new('1', '==', '1')
   #   c.evaluate #=> true
   #
   class Condition #:nodoc:
@@ -96,10 +96,10 @@ module Liquid
       # If the operator is empty this means that the decision statement is just
       # a single variable. We can just poll this variable from the context and
       # return this as the result.
-      return context.evaluate(left) if op == nil
+      return context[left] if op == nil
 
-      left = context.evaluate(left)
-      right = context.evaluate(right)
+      left = context[left]
+      right = context[right]
 
       operation = self.class.operators[op] || raise(Liquid::ArgumentError.new("Unknown operator #{op}"))
 

lib/liquid/context.rb

@@ -24,6 +24,7 @@ module Liquid
       @resource_limits  = resource_limits || Template.default_resource_limits.dup
       @resource_limits[:render_score_current] = 0
       @resource_limits[:assign_score_current] = 0
+      @parsed_expression = Hash.new{ |cache, markup| cache[markup] = Expression.parse(markup) }
       squash_instance_assigns_with_environments
 
       @this_stack_used = false
@@ -169,7 +170,7 @@ module Liquid
     # Example:
     #   products == empty #=> products.empty?
     def [](expression)
-      evaluate(Expression.parse(expression))
+      evaluate(@parsed_expression[expression])
     end
 
     def has_key?(key)

lib/liquid/profiler/hooks.rb

@@ -12,7 +12,7 @@ module Liquid
 
   class Include < Tag
     def render_with_profiling(context)
-      Profiler.profile_children(context.evaluate(@template_name).to_s) do
+      Profiler.profile_children(@template_name) do
         render_without_profiling(context)
       end
     end

lib/liquid/tags/case.rb

@@ -8,7 +8,7 @@ module Liquid
       @blocks = []
 
       if markup =~ Syntax
-        @left = Expression.parse($1)
+        @left = $1
       else
         raise SyntaxError.new(options[:locale].t("errors.syntax.case".freeze))
       end
@@ -58,7 +58,7 @@ module Liquid
 
         markup = $2
 
-        block = Condition.new(@left, '=='.freeze, Expression.parse($1))
+        block = Condition.new(@left, '=='.freeze, $1)
         block.attach(@nodelist)
         @blocks.push(block)
       end

lib/liquid/tags/cycle.rb

@@ -20,10 +20,10 @@ module Liquid
       case markup
       when NamedSyntax
         @variables = variables_from_string($2)
-        @name = Expression.parse($1)
+        @name = $1
       when SimpleSyntax
         @variables = variables_from_string(markup)
-        @name = @variables.to_s
+        @name = "'#{@variables.to_s}'"
       else
         raise SyntaxError.new(options[:locale].t("errors.syntax.cycle".freeze))
       end
@@ -33,9 +33,9 @@ module Liquid
       context.registers[:cycle] ||= Hash.new(0)
 
       context.stack do
-        key = context.evaluate(@name)
+        key = context[@name]
         iteration = context.registers[:cycle][key]
-        result = context.evaluate(@variables[iteration])
+        result = context[@variables[iteration]]
         iteration += 1
         iteration  = 0  if iteration >= @variables.size
         context.registers[:cycle][key] = iteration
@@ -48,7 +48,7 @@ module Liquid
     def variables_from_string(markup)
       markup.split(',').collect do |var|
         var =~ /\s*(#{QuotedFragment})\s*/o
-        $1 ? Expression.parse($1) : nil
+        $1 ? $1 : nil
       end.compact
     end
   end

lib/liquid/tags/for.rb

@@ -68,19 +68,19 @@ module Liquid
     def render(context)
       context.registers[:for] ||= Hash.new(0)
 
-      collection = context.evaluate(@collection_name)
+      collection = context[@collection_name]
       collection = collection.to_a if collection.is_a?(Range)
 
       # Maintains Ruby 1.8.7 String#each behaviour on 1.9
       return render_else(context) unless iterable?(collection)
 
-      from = if @from == :continue
+      from = if @attributes['offset'.freeze] == 'continue'.freeze
         context.registers[:for][@name].to_i
       else
-        context.evaluate(@from).to_i
+        context[@attributes['offset'.freeze]].to_i
       end
 
-      limit = context.evaluate(@limit)
+      limit = context[@attributes['limit'.freeze]]
       to    = limit ? limit.to_i + from : nil
 
       segment = Utils.slice_collection(collection, from, to)
@@ -128,12 +128,12 @@ module Liquid
     def lax_parse(markup)
       if markup =~ Syntax
         @variable_name = $1
-        collection_name = $2
+        @collection_name = $2
+        @name = "#{$1}-#{$2}"
         @reversed = $3
-        @name = "#{@variable_name}-#{collection_name}"
-        @collection_name = Expression.parse(collection_name)
+        @attributes = {}
         markup.scan(TagAttributes) do |key, value|
-          set_attribute(key, value)
+          @attributes[key] = value
         end
       else
         raise SyntaxError.new(options[:locale].t("errors.syntax.for".freeze))
@@ -144,36 +144,24 @@ module Liquid
       p = Parser.new(markup)
       @variable_name = p.consume(:id)
       raise SyntaxError.new(options[:locale].t("errors.syntax.for_invalid_in".freeze))  unless p.id?('in'.freeze)
-      collection_name = p.expression
-      @name = "#{@variable_name}-#{collection_name}"
-      @collection_name = Expression.parse(collection_name)
+      @collection_name = p.expression
+      @name = "#{@variable_name}-#{@collection_name}"
       @reversed = p.id?('reversed'.freeze)
 
+      @attributes = {}
       while p.look(:id) && p.look(:colon, 1)
         unless attribute = p.id?('limit'.freeze) || p.id?('offset'.freeze)
           raise SyntaxError.new(options[:locale].t("errors.syntax.for_invalid_attribute".freeze))
         end
         p.consume
-        set_attribute(attribute, p.expression)
+        val = p.expression
+        @attributes[attribute] = val
       end
       p.consume(:end_of_string)
     end
 
     private
 
-    def set_attribute(key, expr)
-      case key
-      when 'offset'.freeze
-        @from = if expr == 'continue'.freeze
-          :continue
-        else
-          Expression.parse(expr)
-        end
-      when 'limit'.freeze
-        @limit = Expression.parse(expr)
-      end
-    end
-
     def render_else(context)
       return @else_block ? [render_all(@else_block, context)] : ''.freeze
     end

lib/liquid/tags/if.rb

@@ -60,14 +60,14 @@ module Liquid
         expressions = markup.scan(ExpressionsAndOperators)
         raise(SyntaxError.new(options[:locale].t("errors.syntax.if".freeze))) unless expressions.pop =~ Syntax
 
-        condition = Condition.new(Expression.parse($1), $2, Expression.parse($3))
+        condition = Condition.new($1, $2, $3)
 
         while not expressions.empty?
           operator = expressions.pop.to_s.strip
 
           raise(SyntaxError.new(options[:locale].t("errors.syntax.if".freeze))) unless expressions.pop.to_s =~ Syntax
 
-          new_condition = Condition.new(Expression.parse($1), $2, Expression.parse($3))
+          new_condition = Condition.new($1, $2, $3)
           raise(SyntaxError.new(options[:locale].t("errors.syntax.if".freeze))) unless BOOLEAN_OPERATORS.include?(operator)
           new_condition.send(operator, condition)
           condition = new_condition
@@ -92,9 +92,9 @@ module Liquid
       end
 
       def parse_comparison(p)
-        a = Expression.parse(p.expression)
+        a = p.expression
         if op = p.consume?(:comparison)
-          b = Expression.parse(p.expression)
+          b = p.expression
           Condition.new(a, op, b)
         else
           Condition.new(a)

lib/liquid/tags/include.rb

@@ -22,16 +22,12 @@ module Liquid
 
       if markup =~ Syntax
 
-        template_name = $1
-        variable_name = $3
-
-        @variable_name = Expression.parse(variable_name || template_name[1..-2])
-        @context_variable_name = template_name[1..-2].split('/'.freeze).last
-        @template_name = Expression.parse(template_name)
+        @template_name = $1
+        @variable_name = $3
         @attributes    = {}
 
         markup.scan(TagAttributes) do |key, value|
-          @attributes[key] = Expression.parse(value)
+          @attributes[key] = value
         end
 
       else
@@ -44,20 +40,21 @@ module Liquid
 
     def render(context)
       partial = load_cached_partial(context)
-      variable = context.evaluate(@variable_name)
+      variable = context[@variable_name || @template_name[1..-2]]
 
       context.stack do
         @attributes.each do |key, value|
-          context[key] = context.evaluate(value)
+          context[key] = context[value]
         end
 
+        context_variable_name = @template_name[1..-2].split('/'.freeze).last
         if variable.is_a?(Array)
           variable.collect do |var|
-            context[@context_variable_name] = var
+            context[context_variable_name] = var
             partial.render(context)
           end
         else
-          context[@context_variable_name] = variable
+          context[context_variable_name] = variable
           partial.render(context)
         end
       end
@@ -66,7 +63,7 @@ module Liquid
     private
       def load_cached_partial(context)
         cached_partials = context.registers[:cached_partials] || {}
-        template_name = context.evaluate(@template_name)
+        template_name = context[@template_name]
 
         if cached = cached_partials[template_name]
           return cached
@@ -84,9 +81,9 @@ module Liquid
         # make read_template_file call backwards-compatible.
         case file_system.method(:read_template_file).arity
         when 1
-          file_system.read_template_file(context.evaluate(@template_name))
+          file_system.read_template_file(context[@template_name])
         when 2
-          file_system.read_template_file(context.evaluate(@template_name), context)
+          file_system.read_template_file(context[@template_name], context)
         else
           raise ArgumentError, "file_system.read_template_file expects two parameters: (template_name, context)"
         end

lib/liquid/tags/table_row.rb

@@ -6,10 +6,10 @@ module Liquid
       super
       if markup =~ Syntax
         @variable_name = $1
-        @collection_name = Expression.parse($2)
+        @collection_name = $2
         @attributes = {}
         markup.scan(TagAttributes) do |key, value|
-          @attributes[key] = Expression.parse(value)
+          @attributes[key] = value
         end
       else
         raise SyntaxError.new(options[:locale].t("errors.syntax.table_row".freeze))
@@ -17,16 +17,16 @@ module Liquid
     end
 
     def render(context)
-      collection = context.evaluate(@collection_name) or return ''.freeze
+      collection = context[@collection_name] or return ''.freeze
 
-      from = @attributes.key?('offset'.freeze) ? context.evaluate(@attributes['offset'.freeze]).to_i : 0
-      to = @attributes.key?('limit'.freeze) ? from + context.evaluate(@attributes['limit'.freeze]).to_i : nil
+      from = @attributes['offset'.freeze] ? context[@attributes['offset'.freeze]].to_i : 0
+      to = @attributes['limit'.freeze] ? from + context[@attributes['limit'.freeze]].to_i : nil
 
       collection = Utils.slice_collection(collection, from, to)
 
       length = collection.length
 
-      cols = context.evaluate(@attributes['cols'.freeze]).to_i
+      cols = context[@attributes['cols'.freeze]].to_i
 
       row = 1
       col = 0