1 files changed, 111 insertions, 0 deletions
diff --git a/storage/mroonga/vendor/groonga/lib/mrb/scripts/expression_tree_builder.rb b/storage/mroonga/vendor/groonga/lib/mrb/scripts/expression_tree_builder.rb
new file mode 100644
index 00000000..f2cc297c
--- /dev/null
+++ b/storage/mroonga/vendor/groonga/lib/mrb/scripts/expression_tree_builder.rb
@@ -0,0 +1,111 @@
+require "expression_tree"
+
+module Groonga
+  class ExpressionTreeBuilder
+    RELATION_OPERATORS = [
+      Operator::MATCH,
+      Operator::NEAR,
+      Operator::NEAR2,
+      Operator::SIMILAR,
+      Operator::PREFIX,
+      Operator::SUFFIX,
+      Operator::EQUAL,
+      Operator::NOT_EQUAL,
+      Operator::LESS,
+      Operator::GREATER,
+      Operator::LESS_EQUAL,
+      Operator::GREATER_EQUAL,
+      Operator::GEO_WITHINP5,
+      Operator::GEO_WITHINP6,
+      Operator::GEO_WITHINP8,
+      Operator::TERM_EXTRACT,
+      Operator::REGEXP,
+      Operator::FUZZY,
+    ]
+
+    ARITHMETIC_OPERATORS = [
+      Operator::BITWISE_OR,
+      Operator::BITWISE_XOR,
+      Operator::BITWISE_AND,
+      Operator::BITWISE_NOT,
+      Operator::SHIFTL,
+      Operator::SHIFTR,
+      Operator::SHIFTRR,
+      Operator::PLUS,
+      Operator::MINUS,
+      Operator::STAR,
+      Operator::MOD,
+    ]
+
+    LOGICAL_OPERATORS = [
+      Operator::AND,
+      Operator::OR,
+      Operator::AND_NOT,
+      Operator::ADJUST,
+    ]
+
+    def initialize(expression)
+      @expression = expression
+    end
+
+    def build
+      stack = []
+      codes = @expression.codes
+      codes.each do |code|
+        case code.op
+        when *LOGICAL_OPERATORS
+          right = stack.pop
+          left = stack.pop
+          nodes = []
+          add_logical_operation_node(code.op, nodes, left)
+          add_logical_operation_node(code.op, nodes, right)
+          node = ExpressionTree::LogicalOperation.new(code.op, nodes)
+          stack.push(node)
+        when *RELATION_OPERATORS, *ARITHMETIC_OPERATORS
+          right = stack.pop
+          left = stack.pop
+          node = ExpressionTree::BinaryOperation.new(code.op, left, right)
+          stack.push(node)
+        when Operator::GET_VALUE
+          node = ExpressionTree::Variable.new(code.value)
+          stack.push(node)
+        when Operator::PUSH
+          case code.value
+          when Procedure
+            node = ExpressionTree::Procedure.new(code.value)
+          when IndexColumn
+            node = ExpressionTree::IndexColumn.new(code.value)
+          when Accessor
+            node = ExpressionTree::Accessor.new(code.value)
+          when HashTable
+            node = ExpressionTree::Options.new(code.value)
+          else
+            node = ExpressionTree::Constant.new(code.value.value)
+          end
+          stack.push(node)
+        when Operator::CALL
+          arguments = []
+          (code.n_args - 1).times do
+            arguments.unshift(stack.pop)
+          end
+          procedure = stack.pop
+          node = ExpressionTree::FunctionCall.new(procedure, arguments)
+          stack.push(node)
+        else
+          raise "unknown operator: #{code.inspect}"
+        end
+      end
+      stack.pop
+    end
+
+    private
+    def add_logical_operation_node(operator, nodes, node)
+      if node.is_a?(ExpressionTree::LogicalOperation) and
+          node.operator == operator
+        nodes.concat(node.nodes)
+      else
+        nodes << node
+      end
+    end
+  end
+end