Add bin and edit workflow

bin/gems/liquid-4.0.4/lib/liquid/condition.rb

@@ -0,0 +1,151 @@
+module Liquid
+  # Container for liquid nodes which conveniently wraps decision making logic
+  #
+  # Example:
+  #
+  #   c = Condition.new(1, '==', 1)
+  #   c.evaluate #=> true
+  #
+  class Condition #:nodoc:
+    @@operators = {
+      '=='.freeze => ->(cond, left, right) {  cond.send(:equal_variables, left, right) },
+      '!='.freeze => ->(cond, left, right) { !cond.send(:equal_variables, left, right) },
+      '<>'.freeze => ->(cond, left, right) { !cond.send(:equal_variables, left, right) },
+      '<'.freeze  => :<,
+      '>'.freeze  => :>,
+      '>='.freeze => :>=,
+      '<='.freeze => :<=,
+      'contains'.freeze => lambda do |cond, left, right|
+        if left && right && left.respond_to?(:include?)
+          right = right.to_s if left.is_a?(String)
+          left.include?(right)
+        else
+          false
+        end
+      end
+    }
+
+    def self.operators
+      @@operators
+    end
+
+    attr_reader :attachment, :child_condition
+    attr_accessor :left, :operator, :right
+
+    def initialize(left = nil, operator = nil, right = nil)
+      @left = left
+      @operator = operator
+      @right = right
+      @child_relation  = nil
+      @child_condition = nil
+    end
+
+    def evaluate(context = Context.new)
+      condition = self
+      result = nil
+      loop do
+        result = interpret_condition(condition.left, condition.right, condition.operator, context)
+
+        case condition.child_relation
+        when :or
+          break if result
+        when :and
+          break unless result
+        else
+          break
+        end
+        condition = condition.child_condition
+      end
+      result
+    end
+
+    def or(condition)
+      @child_relation = :or
+      @child_condition = condition
+    end
+
+    def and(condition)
+      @child_relation = :and
+      @child_condition = condition
+    end
+
+    def attach(attachment)
+      @attachment = attachment
+    end
+
+    def else?
+      false
+    end
+
+    def inspect
+      "#<Condition #{[@left, @operator, @right].compact.join(' '.freeze)}>"
+    end
+
+    protected
+
+    attr_reader :child_relation
+
+    private
+
+    def equal_variables(left, right)
+      if left.is_a?(Liquid::Expression::MethodLiteral)
+        if right.respond_to?(left.method_name)
+          return right.send(left.method_name)
+        else
+          return nil
+        end
+      end
+
+      if right.is_a?(Liquid::Expression::MethodLiteral)
+        if left.respond_to?(right.method_name)
+          return left.send(right.method_name)
+        else
+          return nil
+        end
+      end
+
+      left == right
+    end
+
+    def interpret_condition(left, right, op, context)
+      # 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?
+
+      left = context.evaluate(left)
+      right = context.evaluate(right)
+
+      operation = self.class.operators[op] || raise(Liquid::ArgumentError.new("Unknown operator #{op}"))
+
+      if operation.respond_to?(:call)
+        operation.call(self, left, right)
+      elsif left.respond_to?(operation) && right.respond_to?(operation) && !left.is_a?(Hash) && !right.is_a?(Hash)
+        begin
+          left.send(operation, right)
+        rescue ::ArgumentError => e
+          raise Liquid::ArgumentError.new(e.message)
+        end
+      end
+    end
+
+    class ParseTreeVisitor < Liquid::ParseTreeVisitor
+      def children
+        [
+          @node.left, @node.right,
+          @node.child_condition, @node.attachment
+        ].compact
+      end
+    end
+  end
+
+  class ElseCondition < Condition
+    def else?
+      true
+    end
+
+    def evaluate(_context)
+      true
+    end
+  end
+end