Merge pull request #239 from locomotivecms/new-attribute-parser

New attribute parser for the with_scope tag

.github/workflows/continuous_integration.yml

@@ -32,7 +32,7 @@ jobs:
       - name: Setup Ruby
         uses: ruby/setup-ruby@v1
         with:
-          ruby-version: 3.1.4
+          ruby-version: 3.3.5
           bundler-cache: true
           cache-version: 1
 

Gemfile

@@ -32,5 +32,5 @@ group :test do
 
   gem 'rack-test',          '~> 2.1.0'
 
-  gem 'simplecov',                  '~> 0.22.0', require: false
+  gem 'simplecov',          '~> 0.22.0', require: false
 end

Gemfile.lock

@@ -18,6 +18,7 @@ PATH
       morphine (~> 0.1.1)
       multi_json (~> 1.15.0)
       nokogiri (~> 1.15.6)
+      parser (~> 3.3)
       pony (~> 1.12)
       rack-cache (>= 1.7, < 2)
       rack-rewrite (~> 1.5.1)
@@ -41,6 +42,7 @@ GEM
       tzinfo (~> 2.0)
     addressable (2.8.7)
       public_suffix (>= 2.0.2, < 7.0)
+    ast (2.4.2)
     attr_extras (7.1.0)
     base64 (0.2.0)
     bcrypt (3.1.20)
@@ -120,9 +122,10 @@ GEM
     nokogiri (1.15.6)
       mini_portile2 (~> 2.8.2)
       racc (~> 1.4)
-    nokogiri (1.15.6-x86_64-darwin)
-      racc (~> 1.4)
     origin (2.3.1)
+    parser (3.3.5.0)
+      ast (~> 2.4.1)
+      racc
     pony (1.13.1)
       mail (>= 2.0)
     public_suffix (6.0.0)

lib/locomotive/steam/liquid.rb

@@ -1,4 +1,6 @@
 require 'liquid'
+require 'parser/current'
+require 'ast'
 
 require_relative 'liquid/errors'
 require_relative 'liquid/patches'
@@ -7,6 +9,6 @@
 require_relative 'liquid/drops/i18n_base'
 require_relative 'liquid/tags/hybrid'
 require_relative 'liquid/tags/concerns/section'
-require_relative 'liquid/tags/concerns/attributes'
+require_relative 'liquid/tags/concerns/simple_attributes_parser'
 require_relative 'liquid/tags/section'
 require_relative_all %w(. drops filters tags/concerns tags), 'liquid'

lib/locomotive/steam/liquid/tags/concerns/attributes_evaluator.rb

@@ -0,0 +1,63 @@
+module Locomotive
+  module Steam
+    module Liquid
+      module Tags
+        module Concerns
+
+          # Evaluates the attributes parsed the AttributesParser
+          module AttributesEvaluator
+            extend ActiveSupport::Concern
+
+            included do
+              # Regexps are allowed as strings
+              RegexpFragment        = /\/([^\/]+)\/([imx]+)?/o.freeze
+              StrictRegexpFragment  = /\A#{RegexpFragment}\z/o.freeze
+
+              REGEX_OPTIONS = {
+                'i' => Regexp::IGNORECASE,
+                'm' => Regexp::MULTILINE,
+                'x' => Regexp::EXTENDED
+              }.freeze
+            end
+
+            protected
+
+            def evaluate_attributes(context)
+              @attributes = context[attributes_var_name] || {} if attributes_var_name.present?
+
+              attributes.inject({}) do |memo, (key, value)|
+                # _slug instead of _permalink
+                _key = key.to_s == '_permalink' ? '_slug' : key.to_s
+
+                memo.merge({ _key => evaluate_attribute(context, value) })
+              end
+            end
+
+            def evaluate_attribute(context, value)
+              case value
+              when Array 
+                value.map { |v| evaluate_attribute(context, v) }
+              when Hash
+                Hash[value.map { |k, v| [k.to_s, evaluate_attribute(context, v)] }]
+              when StrictRegexpFragment
+                create_regexp($1, $2)
+              when ::Liquid::VariableLookup
+                evaluated_value = context.evaluate(value)
+                evaluated_value.respond_to?(:_id) ? evaluated_value.send(:_source) : evaluate_attribute(context, evaluated_value)
+              else 
+                value
+              end
+            end
+
+            def create_regexp(value, unparsed_options)
+              options = unparsed_options.blank? ? nil : unparsed_options.split('').uniq.inject(0) do |_options, letter|
+                _options |= REGEX_OPTIONS[letter]
+              end
+              Regexp.new(value, options)
+            end
+          end
+        end
+      end
+    end
+  end
+end

lib/locomotive/steam/liquid/tags/concerns/attributes_parser.rb

@@ -0,0 +1,156 @@
+module Locomotive
+  module Steam
+    module Liquid
+      module Tags
+        module Concerns
+
+          # The with_scope liquid tag lets the developer use a Ruby syntax to 
+          # pass options which is difficult to implement with the Liquid parsing 
+          # approach (see the SimpleAttributesParser for instance)
+          module AttributesParser
+            extend ActiveSupport::Concern
+
+            included do
+              # Mongoid operators available on symbols
+              OPERATORS = %w(all exists gt gte in lt lte ne nin size near within)
+
+              SYMBOL_OPERATORS_REGEXP = /(\w+\.(#{OPERATORS.join('|')})){1}\s*\:/o
+            end
+
+            def parse_markup(markup)
+              parser = self.class.current_parser
+
+              # 'liquid_code.rb' is purely arbitrary
+              source_buffer = ::Parser::Source::Buffer.new('liquid_code.rb')
+              source_buffer.source = "{%s}" % clean_markup(markup)
+
+              ast = parser.parse(source_buffer)
+              AstProcessor.new.process(ast)
+            end
+
+            private
+
+            def clean_markup(markup)
+              # convert symbol operators into valid ruby code
+              markup.gsub(SYMBOL_OPERATORS_REGEXP, ':"\1" =>')
+            end
+
+            class_methods do
+              def current_parser
+                (@current_parser ||= build_parser).tap do |parser|
+                  parser.reset
+                end
+              end
+
+              def build_parser
+                ::Parser::CurrentRuby.new.tap do |parser|
+                  # Silent the error instead of logging them to STDERR (default behavior of the parser)
+                  parser.diagnostics.consumer = ->(message) { true }
+                end
+              end
+            end
+
+            class AstProcessor
+              include AST::Processor::Mixin
+
+              def on_hash(node)
+                nodes = process_all(node)
+                nodes.inject({}) { |memo, sub_hash| memo.merge(sub_hash) }
+              end
+
+              def on_pair(node)
+                key_expr, right_expr = *node
+                { process(key_expr) => process(right_expr) }
+              end
+
+              def on_sym(node)
+                node.children.first.to_sym
+              end
+
+              def on_array(node)
+                process_all(node)
+              end
+
+              def on_int(node)
+                node.children.first.to_i
+              end
+
+              def on_float(node)
+                node.children.first.to_f
+              end
+
+              def on_str(node)
+                node.children.first.to_s
+              end
+
+              def on_true(node)
+                true
+              end
+
+              def on_false(node)
+                false
+              end
+
+              def on_regexp(node)
+                regexp_expr, opts_expr = *node
+                Regexp.new(process(regexp_expr), process(opts_expr))
+              end
+
+              def on_regopt(node)
+                node.children ? node.children.join('') : nil
+              end
+
+              def on_deep_send(node)
+                source_expr, name_expr = *node
+
+                if source_expr.nil?
+                  [name_expr.to_s]
+                elsif source_expr.type == :send
+                  process(source_expr.updated(:deep_send, nil)) << name_expr.to_s
+                else
+                  raise 'NOT IMPLEMENTED [DEEP_SEND]' # TODO
+                end
+              end
+
+              def on_send(node)
+                source_expr, name_expr = *node
+
+                if source_expr.nil?
+                  ::Liquid::Expression.parse(name_expr.to_s)
+                elsif name_expr == :+ 
+                  process(source_expr)
+                elsif source_expr.type == :send
+                  ::Liquid::Expression.parse(
+                    (process(source_expr.updated(:deep_send, nil)) << name_expr.to_s).join('.')
+                  )                
+                else
+                  raise 'NOT IMPLEMENTED [SEND]' # TODO
+                end
+              end
+
+              # HACK: override the default process implementation
+              def process(node)
+                return if node.nil?
+
+                node = node.to_ast
+
+                # Invoke a specific handler
+                on_handler = :"on_#{node.type}"
+                if respond_to? on_handler
+                  new_node = send on_handler, node
+                else
+                  new_node = handler_missing(node)
+                end
+
+                # fix: the original method considered false as nil which is incorrect
+                node = new_node unless new_node.nil?
+
+                node
+              end
+            end
+          end
+        end
+      end
+    end
+  end
+end

lib/locomotive/steam/liquid/tags/concerns/attributes.rb → lib/locomotive/steam/liquid/tags/concerns/simple_attributes_parser.rb

@@ -7,8 +7,7 @@ module Concerns
           # Many of Liquid tags have attributes (like options)
           # This module makes sure we use the same reliable way to
           # extract and evaluate them.
-
-          module Attributes
+          module SimpleAttributesParser
 
             attr_reader :attributes, :raw_attributes
 

lib/locomotive/steam/liquid/tags/consume.rb

@@ -15,7 +15,7 @@ module Tags
         #
         class Consume < ::Liquid::Block
 
-          include Concerns::Attributes
+          include Concerns::SimpleAttributesParser
 
           Syntax = /(#{::Liquid::VariableSignature}+)\s*from\s*(#{::Liquid::QuotedFragment}+),?(.+)?/o.freeze
 

lib/locomotive/steam/liquid/tags/editable/base.rb

@@ -5,7 +5,7 @@ module Tags
         module Editable
           class Base < ::Liquid::Block
 
-            include Concerns::Attributes
+            include Concerns::SimpleAttributesParser
 
             Syntax = /(#{::Liquid::QuotedFragment})(\s*,\s*#{::Liquid::Expression}+)?/o
 

lib/locomotive/steam/liquid/tags/inherited_block.rb

@@ -15,7 +15,7 @@ module Tags
         #
         class InheritedBlock < ::Liquid::Block
 
-          include Concerns::Attributes
+          include Concerns::SimpleAttributesParser
 
           SYNTAX = /(#{::Liquid::QuotedFragment}+)/o
 

lib/locomotive/steam/liquid/tags/link_to.rb

@@ -4,7 +4,7 @@ module Liquid
       module Tags
         class LinkTo < Hybrid
 
-          include Concerns::Attributes
+          include Concerns::SimpleAttributesParser
           include Concerns::I18nPage
           include Concerns::Path
 

lib/locomotive/steam/liquid/tags/locale_switcher.rb

@@ -19,10 +19,9 @@ module Tags
         #   - "iso" is the default choice for label
         #   - " | " is the default separating code
         #
-
         class LocaleSwitcher < ::Liquid::Tag
 
-          include Concerns::Attributes
+          include Concerns::SimpleAttributesParser
           include Concerns::I18nPage
 
           attr_reader :attributes, :site, :page, :current_locale, :url_builder

lib/locomotive/steam/liquid/tags/model_form.rb

@@ -18,7 +18,7 @@ module Tags
         #
         class ModelForm < ::Liquid::Block
 
-          include Concerns::Attributes
+          include Concerns::SimpleAttributesParser
 
           Syntax = /(#{::Liquid::QuotedFragment})\s*,*(.*)?/o.freeze
 

lib/locomotive/steam/liquid/tags/paginate.rb

@@ -15,7 +15,7 @@ module Tags
         #
         class Paginate < ::Liquid::Block
 
-          include Concerns::Attributes
+          include Concerns::SimpleAttributesParser
 
           Syntax = /(#{::Liquid::QuotedFragment}+)\s+by\s+(#{::Liquid::QuotedFragment}+)/o
 

lib/locomotive/steam/liquid/tags/path_to.rb

@@ -4,7 +4,7 @@ module Liquid
       module Tags
         class PathTo < ::Liquid::Tag
 
-          include Concerns::Attributes
+          include Concerns::SimpleAttributesParser
           include Concerns::I18nPage
           include Concerns::Path
 

lib/locomotive/steam/liquid/tags/redirect_to.rb

@@ -5,7 +5,7 @@ module Tags
 
         class RedirectTo < ::Liquid::Tag
 
-          include Concerns::Attributes
+          include Concerns::SimpleAttributesParser
           include Concerns::I18nPage
           include Concerns::Path
 

lib/locomotive/steam/liquid/tags/section.rb

@@ -5,7 +5,7 @@ module Tags
         class Section < ::Liquid::Include
 
           include Concerns::Section
-          include Concerns::Attributes
+          include Concerns::SimpleAttributesParser
 
           Syntax = /(#{::Liquid::QuotedString}|#{::Liquid::VariableSignature}+)\s*,*(.*)?/o.freeze