ArraySection

A part of an array, with the same rank or a lower one.

Declaration

Syntax

ArraySection(expr v, array_index* args, ttype type, expr? value)

Arguments

Argument

Description

v

the array.

args

one array_index per dimension. A dimension with left, right and step is a range; a dimension with only right is a single subscript and does not appear in the result.

type

the array type of the result.

value

the compile time value of the expression, when the frontend could fold it; nil otherwise.

Return values

The value of the expression.

Description

a(1:3) or a(2, :). The result is an array, and a section that fixes a subscript in one dimension has a lower rank than the array it came from.

A section is not necessarily contiguous, so its type usually has a descriptor physical type: the stride has to be carried along with the data.

Examples

(ArraySection
  :v (Var
    :v (SymbolRef 1 "a")
  )
  :args [
    (array_index
      :left (IntegerConstant
        :n 1
        :type (Integer
          :kind 4
        )
        :intboz_type :Decimal
      )
      :right (IntegerConstant
        :n 3
        :type (Integer
          :kind 4
        )
        :intboz_type :Decimal
      )
      :step (IntegerConstant
        :n 1
        :type (Integer
          :kind 4
        )
        :intboz_type :Decimal
      )
    )
  ]
  :type (Array
    :type (Integer
      :kind 4
    )
    :dims [
      (dimension
        :start (IntegerConstant
          :n 1
          :type (Integer
            :kind 4
          )
          :intboz_type :Decimal
        )
        :length (IntegerConstant
          :n 3
          :type (Integer
            :kind 4
          )
          :intboz_type :Decimal
        )
      )
    ]
    :physical_type :DescriptorArray
    :memory_space :Global
  )
  :value nil
)

It comes from this complete ASR text document:

(TranslationUnit
  :symtab (SymbolTable
    :id 0
    :symbols {
      "main" (Program
        :symtab (SymbolTable
          :id 1
          :symbols {
            "a" (Variable
              :parent_symtab 1
              :name "a"
              :dependencies []
              :intent :Local
              :symbolic_value nil
              :value nil
              :storage :Default
              :type (Array
                :type (Integer
                  :kind 4
                )
                :dims [
                  (dimension
                    :start (IntegerConstant
                      :n 1
                      :type (Integer
                        :kind 4
                      )
                      :intboz_type :Decimal
                    )
                    :length (IntegerConstant
                      :n 3
                      :type (Integer
                        :kind 4
                      )
                      :intboz_type :Decimal
                    )
                  )
                ]
                :physical_type :FixedSizeArray
                :memory_space :Global
              )
              :type_declaration nil
              :abi :Source
              :access :Public
              :presence :Required
              :value_attr false
              :target_attr false
              :contiguous_attr false
              :bindc_name nil
              :is_volatile false
              :is_protected false
              :pass_attr :NotMethod
              :self_argument nil
              :codims []
            )
            "b" (Variable
              :parent_symtab 1
              :name "b"
              :dependencies []
              :intent :Local
              :symbolic_value nil
              :value nil
              :storage :Default
              :type (Array
                :type (Integer
                  :kind 4
                )
                :dims [
                  (dimension
                    :start (IntegerConstant
                      :n 1
                      :type (Integer
                        :kind 4
                      )
                      :intboz_type :Decimal
                    )
                    :length (IntegerConstant
                      :n 3
                      :type (Integer
                        :kind 4
                      )
                      :intboz_type :Decimal
                    )
                  )
                ]
                :physical_type :FixedSizeArray
                :memory_space :Global
              )
              :type_declaration nil
              :abi :Source
              :access :Public
              :presence :Required
              :value_attr false
              :target_attr false
              :contiguous_attr false
              :bindc_name nil
              :is_volatile false
              :is_protected false
              :pass_attr :NotMethod
              :self_argument nil
              :codims []
            )
            "i" (Variable
              :parent_symtab 1
              :name "i"
              :dependencies []
              :intent :Local
              :symbolic_value nil
              :value nil
              :storage :Default
              :type (Integer
                :kind 4
              )
              :type_declaration nil
              :abi :Source
              :access :Public
              :presence :Required
              :value_attr false
              :target_attr false
              :contiguous_attr false
              :bindc_name nil
              :is_volatile false
              :is_protected false
              :pass_attr :NotMethod
              :self_argument nil
              :codims []
            )
            "l" (Variable
              :parent_symtab 1
              :name "l"
              :dependencies []
              :intent :Local
              :symbolic_value nil
              :value nil
              :storage :Default
              :type (Logical
                :kind 4
              )
              :type_declaration nil
              :abi :Source
              :access :Public
              :presence :Required
              :value_attr false
              :target_attr false
              :contiguous_attr false
              :bindc_name nil
              :is_volatile false
              :is_protected false
              :pass_attr :NotMethod
              :self_argument nil
              :codims []
            )
          }
        )
        :name "main"
        :dependencies []
        :body [
          (Assignment
            :target (Var
              :v (SymbolRef 1 "a")
            )
            :value (ArrayConstant
              :n_data 12
              :data #asr/bytes "010000000200000003000000"
              :type (Array
                :type (Integer
                  :kind 4
                )
                :dims [
                  (dimension
                    :start (IntegerConstant
                      :n 1
                      :type (Integer
                        :kind 4
                      )
                      :intboz_type :Decimal
                    )
                    :length (IntegerConstant
                      :n 3
                      :type (Integer
                        :kind 4
                      )
                      :intboz_type :Decimal
                    )
                  )
                ]
                :physical_type :FixedSizeArray
                :memory_space :Global
              )
              :storage_format :ColMajor
            )
            :overloaded nil
            :realloc_lhs false
            :move_allocation false
          )
          (Assignment
            :target (Var
              :v (SymbolRef 1 "i")
            )
            :value (ArrayItem
              :v (Var
                :v (SymbolRef 1 "a")
              )
              :args [
                (array_index
                  :left nil
                  :right (IntegerConstant
                    :n 2
                    :type (Integer
                      :kind 4
                    )
                    :intboz_type :Decimal
                  )
                  :step nil
                )
              ]
              :type (Integer
                :kind 4
              )
              :storage_format :ColMajor
              :value nil
            )
            :overloaded nil
            :realloc_lhs false
            :move_allocation false
          )
          (Assignment
            :target (Var
              :v (SymbolRef 1 "b")
            )
            :value (ArraySection
              :v (Var
                :v (SymbolRef 1 "a")
              )
              :args [
                (array_index
                  :left (IntegerConstant
                    :n 1
                    :type (Integer
                      :kind 4
                    )
                    :intboz_type :Decimal
                  )
                  :right (IntegerConstant
                    :n 3
                    :type (Integer
                      :kind 4
                    )
                    :intboz_type :Decimal
                  )
                  :step (IntegerConstant
                    :n 1
                    :type (Integer
                      :kind 4
                    )
                    :intboz_type :Decimal
                  )
                )
              ]
              :type (Array
                :type (Integer
                  :kind 4
                )
                :dims [
                  (dimension
                    :start (IntegerConstant
                      :n 1
                      :type (Integer
                        :kind 4
                      )
                      :intboz_type :Decimal
                    )
                    :length (IntegerConstant
                      :n 3
                      :type (Integer
                        :kind 4
                      )
                      :intboz_type :Decimal
                    )
                  )
                ]
                :physical_type :DescriptorArray
                :memory_space :Global
              )
              :value nil
            )
            :overloaded nil
            :realloc_lhs false
            :move_allocation false
          )
          (Assignment
            :target (Var
              :v (SymbolRef 1 "i")
            )
            :value (ArraySize
              :v (Var
                :v (SymbolRef 1 "a")
              )
              :dim (IntegerConstant
                :n 1
                :type (Integer
                  :kind 4
                )
                :intboz_type :Decimal
              )
              :type (Integer
                :kind 4
              )
              :value nil
            )
            :overloaded nil
            :realloc_lhs false
            :move_allocation false
          )
          (Assignment
            :target (Var
              :v (SymbolRef 1 "i")
            )
            :value (ArrayRank
              :v (Var
                :v (SymbolRef 1 "a")
              )
              :type (Integer
                :kind 4
              )
              :value nil
            )
            :overloaded nil
            :realloc_lhs false
            :move_allocation false
          )
          (Assignment
            :target (Var
              :v (SymbolRef 1 "i")
            )
            :value (ArrayBound
              :v (Var
                :v (SymbolRef 1 "a")
              )
              :dim (IntegerConstant
                :n 1
                :type (Integer
                  :kind 4
                )
                :intboz_type :Decimal
              )
              :type (Integer
                :kind 4
              )
              :bound :UBound
              :value nil
            )
            :overloaded nil
            :realloc_lhs false
            :move_allocation false
          )
          (Assignment
            :target (Var
              :v (SymbolRef 1 "l")
            )
            :value (ArrayIsContiguous
              :array (Var
                :v (SymbolRef 1 "a")
              )
              :type (Logical
                :kind 4
              )
              :value nil
            )
            :overloaded nil
            :realloc_lhs false
            :move_allocation false
          )
        ]
      )
    }
  )
  :items []
)

See Also

ArrayItem, array_index, ArrayIsContiguous, ArrayPhysicalCast